Orals Revision Notes

Task – Revision Notes: Manoeuvring

InteractionA vessel moving along experiences unwanted forces caused by the flow of water and unequal pressure around the hull.

A build up of positive pressure builds up ahead of ship caused by water piling up ahead of the vessel trying to resist its fwd movement.

The water down the sides of the ship creates a balancing area of negative pressure.

The negative pressure over compensates the positive pressure so another smaller area of positive pressure astern is created.

These pressure zones not only go outwards they also act vertically downwards.

Bank EffectThis occurs when a vessel is passing a gently shelving bank, the positive pressure forward pushes the bow away from the bank. The Negative pressures draw the stern towards the bank. If the forces are very strong then it may cause the vessel to roll towards the bank increasing the vessels draught.

To control the effect you have to constantly correct the amount of helm that is being applied.

Bow Cushion effectWhen the river banks sides are steep sided the vessel will experience constructive forces. The forward pressure area is partially constrained on the obstructed side and therefore creates a cushion at the bow. As long as the stern is kept far enough away that the negative forces do not create a suction then you can balance the outward turning force of the bow cushion with the inward turning force at the stern, this is done by applying helm towards the bank.If you are navigating in a narrow channel which is constrained on both sides then the bow cushion forces the vessel to take the center line of the channel. If you pass an opening in the channel this loss of pressure will cause the bow to turn towards the opening.

Squat The restriction at the bow causes the speed of water to flow

under the fore foot of the vessel to increase This increase of water causes a low pressure area under the fore

foot to form which in turn leads to a loss of buoyancy at the fore foot.

Due to the loss of buoyancy the bow will dip Due to the bow dipping an increasing amount of water will build

up in resistance This forces the bow deeper dipping the bow further until the

buoyancy is equal to the downward weight of the vessel In addition to what is happening forward the speed of the flow of

the water around the vessel also suffers an increase as it is drawn both along the ships side and down under the hull.

This fall in water level causes the loss of the under keel clearance called SQUAT

Another effect of squat is the reduced steering lever, during a turn this may lead to a sudden or rapid sheer of the vessel. If a vessel does experience sheer then a good burst of power is required to correct the sheer before reducing speed to reduce squat.

Squat = Cb x V 2

K

Cb = the block coefficient V = speed in knotsK = a constant depending upon the depth : draught ratio

K = When the available depth of water is greater than twice the deepest draught then K may be assumed to be 100

K = Where the ratio is between 1 : 1.15 and 1 : 2 then K may be assumed to be 50

Ship to Ship Interaction If two vessels meet head to head the combined positive bow pressures will cause the bows to be repelled

When the vessels are abeam the negative pressure zones cause a suction towards each other

As the vessels are stern to stern the negative pressure causes the vessels to be drawn together

Shallow water In shallow water the size of the turning circle and a loss of speed. This is because in shallow water there is a much greater build up

of lateral resistance caused by the restriction of under keel clearance.

This causes the pivot point to move aft shortening the turning lever

The longitudinal water flow under the keel is increased and so the vessel has to use more power to maintain speed

There is also a restricted lateral flow caused by the increased draught on the outside of the turn.

The result is that the rudder is less effective, the turn is dramatically reduced therefore the angle of drift is much shallower.

Ship SpeedThe following factors effect ships speed:

Boundary Layer Vessels carry a body of water surrounding the whole

body of the ship, this water is on mm thick but it causes a loss of power

Shallow water effect on bow and stern waves In addition to the reduction of under keel clearance

there is an increase of water around the hull which produces a larger bow and stern wave.

In addition to squat the vessel will also have to increase speed to over come the bow and stern waves generated

StoppingThere are six main ways of stopping a vessel using just engines and rudders:

Crash stop Low frequency rudder cycling High frequency rudder cycling Turning under full helm Controlled speed reduction Inertia stop

Crash stop – Putting engines from Full ahead to Full asternThere is a immediate loss of control Much better to reduce to slow ahead then slow astern, the chance of cavitation is reduced and control is maintained for longer

Low frequency rudder cycling – This is designed to take greatest advantage of drift angle which develops as a vessel enters a turn.

High frequency rudder cycling – This relies on the drag on the rudder to reduce headway

Turning under full helm – Good to use when the vessel is not restricted by sea room or depth.This is probably the quickest and most efficient method of taking way off due to the drag on the hull created by the lateral resistance to the turn

Controlled Speed reduction – The most practical way of taking way off the vessel in confined waters Speed is reduced in stages until both vessel and engines are dead slow aheadWhen at Slow ahead then Slow astern is sufficient to stop the vessel

Inertia StopThis is simply stopping the engines and allowing the ship to

stop

The use of anchors for stopping Dredging is particularly effective in eliminating speed and directional control. Having both anchors out shifts the pivot point to a position between the two anchors – this gives improved steering and makes it easier to control the bow. The additional drag created by the anchors is often sufficient to take all way off the vessel The vessel must be moving when the anchors are let go

Clearing a Foul Anchor If the anchor becomes fouled on the sea bed then there are couple of methods that you have to try and break it out –

Heave short and steam slowly over the anchor If this fails pay out some cable and steam around the anchor

position, this should rotate the shank allowing it to break out If this fails you will need to buoy and break the cable.

Clearing a foul hawseWhen a vessel has both anchors out it is inevitable that the vessel will swing round it moorings due to tide and wind. This will result in the anchor cables becoming crossed. Clearing these turns can be tricky, you can do it by gentle engine moments and rudder movements steam round un-twisting the cable. If this fails the foul must be cleared manually.

Heave in so that the foul turns above the water Lash the cables together using natural fiber rope below the turns Pass a preventer wire through the sleeping cable after the turns

and lashing Heave up the preventer wire to act as a slip wire and turn it up

on the bits Walk back on the sleeping cable to expose a joining shackle Make fast the cable below the joining shackle and break the

cable Pass a wire messenger from the port side Make a half turn around the riding cable in the opposite direction

to the turns Pass a wire up the stbd hawse pipe and attach it to the sleeping

cable Heave up on the messenger wire and slack on the easing wire This will remove the turns, one half turn at a time When all the turns have been removed, retrieve the sleeping

cable by heaving on the easing wire Reconnect the joining shackle and remove the preventer wire

Move the lashing between the two cables Heave up and secure the anchors for sea

Hanging off an anchor When a vessel is to moor to a buoy with its own cable it is therefore necessary to hang the anchor off

Walk the anchor out till is clear of the hawse pipe Secure anchor using wires and bottle screws Guillotines should be left in place Pass a wire through the D shackle on the anchor secure one end

to the bits and the other end should be put on the windlass Rig a preventer wire in a slack position Walk back on the anchor till the weight is taken by the wire The wire will now be in the up down position and the preventer

will be tight Pay out anchor until the first join shackle appears on deck Rig an easing wire below the joining shackle and then break the

shackle Slack back on the easing wire until the cable is clear of the

hawse pipe The vessel can now use the broken cable to moor to a buoy.

Open moorThe vessel should approach with the wind and weather approximately six points on the bow with sufficient headway, but not too fast it will cause damage to the anchors

Walk both anchors to the waterline Let go the windward anchor Continue making headway up to windward Steam for 2 ship lengths Let go the Lee anchor Hold on to the windward anchor Rudder amidships and engines half astern this will move the

stern round Pay out on the leeward anchor Stop engines when the sternway comes on The vessel will be brought up when there is equal cable on both

anchors at an angle of about 60º

Standing MoorUsed when the wind and tide are coming from different directions

Stem the tide Let go the upstream anchor Move astern

When the cable is twice the required length let go the down stream anchor

Go ahead on the engines to cant the bow away from the first anchor

Vessel is now back in the middle position Now heave on the upstream anchor and pay out on the

downstream anchor

Open Moor Standing Moor

Running MoorSimilar to the Standing moor except it is carried out differently

Let go down stream anchor when the vessel is still moving ahead

Pay out twice as much cable as is required Let go up stream anchor Pay out the up stream anchor and heave on the down stream

anchor until both lengths are the same

Medi Moor Carried out in the Mediterranean where the wind is fairly predictable and the tide is minimal

Make approach, when one and half ship lengths away let go the offshore anchor

Steam round the anchor then kick ahead on the engines When the bow is one and half lengths past the intended final

position let got he second anchor Come astern on the engines Go astern on to the berth adjusting both anchors so that there is

even weight on both Run stern lines and make fast

Berthing

Port side to no wind or tide Approach with minimum headway at an angle of 25º - 30º The bow should be aimed at a point just short of where you

want to position the ship

Stop engines well in advance and drift in When about a beams width off the berth Hard Stbd Slow astern will cant the stern to port

Stbd side too no wind or tide Make the approach at 15º - 20º Aim roughly where the bow will end up When half a beams width from the berth back spring ashore Dead slow astern Pass a stern line as soon as possible to assist with coming

alongside

Port side too tide from ahead with a gentle on shore breeze Due to the tide there will be much better steering

characteristics due to more water passing over the rudder Stop the vessel when still far away from the berth and assess

the tide and wind strength Aim the bow at the final position Approach at 25º - 30º When about a beams width off the berth round up to stem the

tide Balance this position and wind will bring the vessel alongside

Port side to Tide from dead ahead strong onshore breeze Aim the vessel 50 – 60m ahead of the final position and one a

half beams width off the berth Let go the off shore anchor Now balance the engines so to stem the tide Using the anchor to control the bows closing speed come onto

the berth

Port side to Tide from ahead moderate offshore breeze Aim the bow at the final position Approach at 20º or less to allow for the vessel being blown off

the berth When about a beams width off the berth round up to stem the

tide Balance this position and wind will bring the vessel alongside Pass lines as soon as possible

Avoid when possible approaching a berth with the tide astern of you, unless you have the assistance of tugs.

Navigating in Ice

If a vessel is not down to her marks when navigating in ice you should do all you can to ballast her down ensuring that stability is not compromised

Be aware of ballast water freezing especially in high sided tanks, fill only to 90% full to give some Free surface to it

Trim by the stern as much as possible so that the props and rudders is as deep as possible

Ensure search light is working, if not do not navigate at night Always pass to windward of ice bergs When approaching ice from open water make your entrance

at right angles, slowing down until vessel is nearly stopped Proceed at speed fast enough that you will not cause damage

to the hull and slow enough ice will not form around you When following an ice breaker the idea is to follow in its wake

but don’t get too close to it. If your vessel is in danger of having her props hit a berg then

stop the shafts to avoid damage to the blade tips If your vessel is suffering from ice accretion then turn your

vessel so the relative wind is on the opposite side. Be very careful not to induce stress fractures when using hammers or mattocks.

Tugs

3 types of tug:Conventional Tractor Azimuth stern drive

Conventional Tug Single prop big rudders As soon as she takes a tow the pivot point moves directly under

the towing point If the angle of tow moves dead astern to 45º off the tug will not

be able to return to a position with the tow dead astern without letting the tow go

Tractor Tug 2 Voith Schnieder units Propulsion is fwd of the towing point This means the tug can pull in any direction and girting is much

less of a problem Very expensive + hard to maintain Less bollard pull than a conventional tug

Azimuth Takes the best of both tugs Propulsion is a pair of independently rotating units both mounted

at the stern 2 towing points 1 fwd and 1 aft of mid ships Maneuvers much the same as the conventional tug

Girting Conventional tugs are prone to girting due to the pivot point being fwd of the propulsion units. If the tug repositions or the ship takes a sudden swing then the line of the tow is displaced causing a turning moment, this can heel the tug violently possibly causing it to capsizeTo minimize girting Gob ropes maybe used, this effectively bowses down the tow rope and moves the pivot point aft of the thrust

Task – Revision Notes: Passage Planning

Appraisal – Gathering all the information together: Charts Tidal Streams / atlas’s Publication: Mariners Handbook, ALRS, Pilot Books, Bridge

Procedures Guide Routing Charts Ocean Current Charts Weekly Notices to Mariners M Notices IMO ships Routing Guide to Port entry Distance Tables Ice Charts Ocean Passages for the world Annual Summary notice to mariners

Planning – Putting the lines on the charts and making the passage plan

Execution – Selling and going over the plan with the master

Monitoring – Actually carrying out the plan and monitoring its effectiveness

Weekly Notice to MarinersSection 1 Explanatory Notes, Index for section 2

Contains explanatory notes and advise on the use of charts and publications followed by an index of notices and chart folio index of charts effected together with the geographical region

Section 2 Admiralty Notices to Mariners – Chart corrections Contains notices for correction of charts including notices

effecting navigational charts and are listed consecutively from the onset of the year

Contains T’s and P’s notices relevant to the week. The last weekly notice for each month will also list the T’s and P’s remaining current

Any new addition charts together with new publications issued Latest editions of publications are listed at the end of March,

June, September and December

Section 3 Reprints of Radio warnings Contains all Navarea messages in force with reprints of those

issued in the week Also lists Hydrolants, Hydropacs, US special warnings received

together with reprints in force for the those areas The first weekly notice for each year contains a list of

Navearea, Hydrolant and Hydropac messages

Section 4 Corrections to admiralty sailing directions Contains all corrections affecting Sailing Directions for that

week A cumulative list of these corrections is published each month

Section 5 Corrections to admiralty list of lights and fog signals Contains all corrections for that week

Section 6 Corrections to admiralty list of radio signals Contains all corrections for that week

Routing chartsThe following Information is found on a monthly routing chart:

Ice information – max limit Position of ocean weather ships Recommended tracks and distances Bailie wind rose Areas of predominant poor visibility Mean air temperature guide Wind force guide

Dew point and mean sea temperatures Loadline demarcation limits Ocean Currents

Task – Revision Notes: Gyro

A gyroscope is a heavy wheel which when at high speed will rotate around its spin axis and is free to move around two other axis’s mutually perpendicular to each other. These other two degrees of freedom allow the gyroscope to turn in azimuth and tilt.

Gyroscopic inertia Before the gyro starts to spin its spin axis can be moved in any

direction When it starts spinning it exhibits resistance against efforts to

change the direction of its spin axis this is gyroscopic inertia o Inertia is related to the shape and weight of the gyro, the

distribution of that weight and the rate of spin of the wheelo For the optimum performance you need a wheel with the

weight heaviest around the rim, which is spinning as rapidly as possible

Gyroscopic inertia ensures that the spin axis will continue to be directed towards a fixed point in space

Consequently the movement relative to the earth allows gyroscopic inertia to be divided into tilt and drift

Tilt The vertical movement of a gyro axis relative to the earth

If the gyro is situated at the equator horizontal with the spin axis pointing east the gyros spin axis will steadily tilt upwards so after about 6 hours it will be vertical, it will then start to tilt down wards and after 12 hours it will be pointing west. It will continue downwards until after 18hours it will be pointing vertically downwards, after which it will start to tilt upwards again until it is directly east again. When the gyro is at either pole and horizontal it will follow its representative star around the horizon with no change in tilt.

Drift The horizontal movement of the gyro axis (change in azimuth)

A free gyroscope sited at either pole with its spin axis horizontal will apparently move in a clockwise direction when viewed from above the North Pole – due to the counter clockwise rotation of the earth. It will move in an apparent counterclockwise rotation when viewed from the south pole.When placed on the Equator there will be no drift

PrecessionIf you apply a torque perpendicularly to the spin of the axis the axis will move in a direction perpendicular to that of the applied torque. This is called precession and is the result of the gyro trying to re balance itself to accommodate the two demands made on it.

If the torque applied about the spin axis in the plane wheel its effect is to reduce / increase the speed of rotation – increase / decrease the load on the motor.

To work out which way precession is going to take place you need to know the direction of spin on the wheel. Next you just rotate the torque through 90º in the direction of the spin to ascertain the direction of precession

Torque applied here

Resultant Precession

Gyro CompassPrecession is very useful and is utilised to make the gyro north seeking.Assume:

The axis is horizontal and is pointing to the east at a rising star As the star rises the north end of the axis will tilt upwards If adding weigh to the rotor casing asymmetrically to make it top

or bottom heavy the axis can be made to precess towards the meridian as the gyro tilts

When the gyro is horizontal the added weight is either directly above or below the wheel and causes no torque

This gravity controlled method unfortunately will only make the gyro very crudely north seeking rather than north settling

Methods of gravity controlThe simple method as mentioned above with putting weights directly above or below the spin axis is highly unsatisfactory in a sea way where the weight would be subject to accelerations from rolling and pitching of the vessel

What to do…The system of using liquid ballistics produces a top heavy effect by a high density fluid flowing under gravity from pots on the high side of the assembly which supports the wheel. This fluid is able to flow through a small bore tube to similar pots on the low side. The torque produced by this weight transfer has the same effect as the torque produced by a heavy top weight and results in precession to the meridian.The bore of the tube is such that it resists the surge of liquid when the vessel rolls.

Horizon

Tube

As it tilts the fluid flows to the low side causing a torque, precession returns the gyro back to

Gyro wheel

Gravity control using a pendulum effectThis is basically a pendulum bob which swings to the low side of a spin axis to produce torque, which in turn precesses the gyro towards the meridian. This is also impractical due to the vessel movement.

DampingWithout some means of damping a gravity controlled gyro will continue to follow an elliptical path. If the gyro is going to be useful then the size of this elliptical path must be reduced so that the axis finally settles on the meridian.A gyro may be damped in tilt or damped in azimuth. Damping in tilt is achieved by making any tilt of gyro produce a horizontal torque which results in vertical precession to oppose the tiltDamping in azimuth is achieved by making a vertical torque and horizontal precession, this precession is out of phase with that achieved by the gravity control

Errors of a gyroCourse and speedThe cause and effect of tilt in a gyro has been that the gyro has maintained its position on the earths surface, unfortunately ships compasses are always on the move. When a vessel is steaming North or South its bow is steadily tilting downwards relative to a point in space, this causes unwanted tilting on the gyros spin axisWhen a vessel is steaming East or West there is no tilting so no effect on the gyro. If the gyro was responding to N / S motion it would settle with the spin axis E/W where there was no tilt.As the gyro settles N/S when subject to the earth rotation alone and E/W when subject to the N/S component of ships speed a vector diagram can be drawn to show the error cause by the ships movement.

To correct for these steaming errors is done by correcting latitude and speed this done manually by applying the information to the lubber line by means of a cam and cosine groove. Today latitude and Speed corrections are fed in manually or where it is linked to a GPS it may receive its information from there. In either case the result is fed to a correction torque motor which creates a precession in tilt equal an opposite to the unwanted tilt.

Change of speed errorSteaming error is proportional to the ships speed and the cosine of the course. This normally would not be very high but a vessel navigating at 20kts at lat 70º may get an error of 8º. The gyro will therefore be unreliable for a period time while the axis completes its damped spiral path to the new settling position. Many modern gyro compasses are able to automatically produce a precessing torque that reduces steaming error problems whatever the course / speed / latitude

Questions and answers

What are the three degrees of freedom of a free gyroscope Free to tilt about its Horizontal axis Free to drift about its Vertical axis Free to Spin about its axis

Describe the two notable properties of a free gyro Gyroscopic inertia – The reluctance of the gyro to change its

plane of rotation unless acted upon by an external force, thus the axle tends to maintain the same direction with respect to space, known as rigidity in space

Precession – The movement of the axle of a gyroscope when an external force is applied to it. If a force is applied to one end of the spin axis is will move at right angles to both the applied force and the spin axis. The resultant motion is precession.

Upon what properties does the moment on inertia of a free gyro depend

The speed of the wheel The mass of the wheel The distribution of the mass

What is meant by the terms TILT and DRIFT when applied to the axle of a free gyro

Tilt is any movement up or down Drift is any movement east or west

Is the rate of tilt constant and how can it be calculated

Yes, but it depends on the latitude of the gyro. At the equator, with the gyro spin axis pointing east – west, the axis will appear to tilt east end up, the tilt rate will be 15 per hour and there will be no drift. The tilt can be calculated at latitudes other than the equator by the equation 15 x Cos Latitude + Sin azimuth.

Is the rate of drift constant and how can it be calculated Yes, again it depends on the latitude of the gyro. At the north

pole the gyro spin axis will, when viewed from above, drift clockwise at 15 per hour. There will be no tilt. The drift at latitudes below the north pole can be calculated by 15 x Sin Latitude

Why is a free gyro not suitable as a compass A free gyro is unsuitable as because :

o It is unable to seek the meridiano It must be accurately aligned with the meridian, and be

regularly checked and adjusted.o Frictional torque imposed by the gimble assembly causes

the gyro to drift out of the meridian.o It only passes the meridian twice in 24 hours

Describe how controlled precession is achievedControl precession is achieved in the Sperry gyro by means of a liquid ballistic system. This is fitted to convert a free gyro into a controlled gyro as it provides a means of controlling the drift of a free gyro. This is achieved by fitting pots on either end of the gyro. Each pot is filled with equal amounts of mercury when the spin axis is horizontal. When the north end tilts up mercury transfers from the north pot to the south pot. This has the same effect as putting a downward force on the south end, which results in easterly precession of the south end and westerly precession of the north end. The amount of precession depends on how far the north end is above the horizon. As the north end tilts up Precession will be small, as it continues to tilt it will reach a point when Precession will match the easterly drift of the earth. It will now precess west. When it returns to the meridian there will be no tilt and Precession will be maximum.

Task – Revision Notes: GPS

The GPS system that we predominately use is the NAVSTAR GPS the American system – which stands for Navigation Satellite Timing and Ranging Global Positioning System. Other systems are the GLONASS system and the new Galileo system.

Until recently the civilian access to the system was degraded but in 2000 the Selective Availability was removed.

When selective availability was in use the accuracy was only up to 100m, with the introduction of DGPS which was able to produce accuracy up to 1-3m

The GPS System is made up of 3 parts: Ground Control Segment Space Segment User Segment

Ground Control Segment Master control station

Controls and monitors the satellite orbits Predicts performance and produces ephemeris for all

satellites Information of the health of the satellites is passed to each

satellite so they can pass this on to the usersIn addition to the master control station there are four monitoring station in low latitudes that are evenly space round the world. This is so that satellites are always above the horizon of one or more stationsThe monitoring stations collect data in the ephemeris production, they may also be used to transmit navigation data and commands to the satellites.

Space Segment Satellites operate in six circular orbits inclined to the equator. Each orbit has four active satellites, this configuration ensures that at least 4 satellites are available to a user anywhere on the earths surface.

User SegmentA GPS receiver determines the position of its antenna by simultaneously measuring the ranges from a number of satellites whose positions are accurately known. Basically what actually happens is the receiver measures how far a code signal received from the satellite is out of step with a replica code generated within the receiver. Unfortunately the clock within the receiver is not synchronized exactly with the satellite time so direct calculation of range is not possible. But the errors for the satellite clocks are know and are sent out by the Ground Control Segments.

GPS signals are very weak and spread over a wide band width, therefore the receiver gets good signals and a lot of noise. So that the receiver does not pick up lots of stronger signals the design of the antennae is vital.

The weak signals are amplified as they are sent down the cable to the antennae. Further amplification is carried out in the receiver to pick out and process the code. The receiver’s micro processor then is able to devise the pseudo range.

There are 3 types of receiver on the market Parallel Receiver

1 channel dedicated to each satellite this allows them to access all the satellites continuously and simultaneously

Such receivers achieve better signal noise ratios and better pseudo range results

Parallel receivers are typically used for highly accurate applications such as for surveying

Fast sequencing receivers Do not have dedicated channels They are able to rapidly switch between the channels of the

available satellites Due to the measurements not being made simultaneously which

may result in inaccuracies in the position

Multiplexing receivers These are very fast sequencing But are prone to noise which results in bad positions

Errors within the GPS SystemWGS84GPS provides positions based on WGS84 (World Geodetic System 84) which is a mathematical model of the earth. This requires all current charts to be converted to WGS84 to ensure that they correspond with the actual position. The corrections are usually noted on the charts and obviously this provides a big opportunity for human error.

System Error Despite the constant monitoring of the satellites by control

stations there will be small clock errors and ephemeris errors. Although the combined error is unlikely to give more than a 2m position error.

Ionospheric delay is caused by refraction in the ionosphere, this delay can be calculated and supplied to the user via the Control Stations

Tropospheric delay can not be calculated, this will only produce a small error when using a good receiver

Multi path error refers to an error caused by receiving direct and reflected signals – the receivers in a modern set are programmed to detect this

Noise is likely to cause errors in positions obtained from the GPS, warning of solar activity may be included in this category

Dilution of precision When fixing normally we know that 3 bearings cut at 60º is ideal, the GPS system will automatically select available satellites to provide that accurate fix.The user receives an indication of the accuracy of the fix he has received and the expected current satellite geometry.This is provided by the receiver and available on the display as Dilution of Precision (DOP):

GDOP – Geometric Dillution of Precision applies to four dimensions (N/S, E/W, height and time)

PDOP – Position Dilution of Precision applies to three dimensions (N/S, E/W and height)

HDOP – Horizontal Dilution of Precision is the most valuable to a navigator because it indicates the probable accuracy of the N/S and E/W dimensions)

EDOP – Easting Dilution of Precision is of interest when longitude errors are most critical

NDOP – Northing Dilution of Precision is of interest when latitude accuracy is critical

TDOP – Time Dilution of Precision applies to time accuracy only VDOP – Vertical Dilution of Precision when altitude is critical

If your HDOP reading is 2 then there is a 95% probability that the GPS position is within 200m of the true position.

DGPSA DGPS base station is erected over a known position and the co-ordinates of it are entered into the receiver. Given the true position and the ephemeris of all the satellites the base station receiver is able to calculate a series of true ranges. It simultaneously measures the pseudo range to the same satellites. The difference between the two provides a set of range corrections that is then transmitted to users in the area, resulting in a more accurate position.For DGPS frequencies check the ALRS Vol. 2

Errors with DGPS The maximum separation between the DGPS station and the user

should be 300Nm Noise can result in an error of a number of meters in the pseudo

range Multi path error cannot be removed but receivers compensate for

it

Radar

RADAR stands for Radio Detection and Range

Fundamentally a RADAR is a precision clock which enables the time between a transmitted radio signal leaving the set and the reflected pulse returning to the set to be measured.

RADAR can measure the bearing and distance of most objects at quite long ranges by using radio waves or electro magnetic vibration

The basic set Transmitter – This generates the radio waves

Transmits the high energy radio waves and receives the low energy echoes

Waveguide - Metal tubing that carries the high frequency radio

waves Antennae - This directs the radio waves towards the

objects and receives the echoes

It makes it possible to work out the bearing of the target

It collects the received echoes and directs them towards the receiver

Scanners transmit energy from the magnetron in a narrow beam, this horizontal width of beam is usually defined as the angle between half power points

Receiver - A device that detects the presence of any echoes

and amplifies them ready for display Time base or Trigger - The means of measuring the travel time

of the pulse and echo

Display - The means of showing the echoes in plan form – The

Plan Position Indicator (PPI)

Horizontal beam width

The angle P1 A P2 is the horizontal band width P1 and P2 are the points which a receiver being moved across a

beam at a constant distance from the scanner would register half power

In the diagram above the horizontal band width is greatly exaggerated an in reality it is less than 2º

It is very difficult to design a scanner which only has a main beam and much smaller less powerful beams exist – side lobes

The scanner width and wavelength of the radar frequency determine the horizontal beam width- The wider the scanner the smaller the

Horizontal bandwidthThe shorter the wave length the smaller

the Horizontal bandwidth

Vertical Bandwidth

P1

P2

Main Lobe

Half Power

Half Power

Maximum Power

Side Lobes

A

More complicated than horizontal bandwidth and the way scanners are designed there is much more Vertical bandwidth than Horizontal Bandwidth

The sea surface reflects energy breaking up the vertical pattern into lobes - this is because the waves of energy and reflected waves of energy are sometimes in phase and sometimes out of phase, this results in lobes

The number of vertical lobes formed depends on the wavelength and the height of the scanner

o By taking the length of the vertical line from the scanner to the sea surface and dividing that length by half the wavelength used in the radar pulse you can find the number of vertical lobes

The distance between the vertical lobes increases with distance from the vessel

Radar TransmissionFor a good echo to be produced the radar pulse must:

Have high energy Be of short wavelength to enable to echo to be accurately timed Be generated for only short periods of time to ensure echoes

from nearby objects are detected

Pulse length and Pulse Repetition Frequency Typical pulse lengths:Short 15m 0.5µ secMedium 75m 0.25µ secLong 300m1.00µ secA large number of these pulses are generated every second this is known a Pulse Repetition FrequencyThe interval of time between successive pulses is known as Pulse Repetition IntervalDue to the high speeds of the pulses echoes from targets at a long range will return before the next pulse is transmitted

RADAR’s LimitationsDue to the curvature of the earth there is a limit to what we can see with the naked eye, because light is refracted we are able to see roughly 6% further than the theoretical horizon.RADAR waves are also refracted and because they are at a lower frequency than light they are bent further so the RADAR can see 15% further than the theoretical horizon.

Discrimination Differentiation of targets depends on three factors:

1. Spot size2. Pulse Length3. Horizontal beam width

Spot sizeThe electron beam in the CRT is focused as finely as possible, the degree of focus governs the spot size, this is very much dependent on the range scale in use.

Pulse length A detected echo produces an intensification of the electron beam The duration of the bright spot on the screen is therefore a function of the duration of the received echo – the duration of the echo is the pulse length.Targets which are on the same bearing and closer than half the pulse length will appear as one target – therefore we can say that Range Discrimination is dependent on pulse length and spot size

Range and bearing accuracy Bearing accuracy is governed by:

1. Horizontal Beamwidth2. Scanner to trace sync3. Heading marker4. Aerial squint error

If the scanner to trace synchronization is not correct then there will be errors in bearing:

One revolution of the trace on the CRT must happen in the same time as one revolution of the scanner

The orientation of the picture on the screen must be correct to the orientation of the heading marker

The heading marker is operated by a switch which is activated every time the scanner passes it, this must be adjusted so that the heading marker intersects the picture at the correct point

Squint error This is in a slotted wave guide scanner and is caused when a magnetron produces a slightly different RF pulse from that which the aerial is designed for is introduced into the set.

Errors seen on the PPIFalse EchoesThese echoes may appear on the screen when there is no real target there, there are 6 types:

1. Indirect – Caused by obstructions in the path of the radar beam, Think masts on the Surf when targets would appear in the blind sector when in fact they were ahead of you

2. Sidelobe – When very good target are present at close range there may be sufficient energy returned from the side lobes to generate echoes on the screen, these echoes may appear in an arc on either side of the target

3. Multiple – caused by a radar pulse being reflected backwards and forwards between two reflective surfaces before being received by the scanner

4. Interference – Caused by the radar picking up pulses of other radars operating in the vicinity using a similar transmission frequency and similar pulse repetition frequency. Normally causes a spiraling pattern on the display

5. Second Trace returns – In some cases the echo will return to the scanner after the next pulse has been sent, the system assumes that the echo is from the second pulse and will paint the target accordingly

6. Ghost – This will occur when a vessel is approaching power cables which span a channel, the appearance on a radar screen is that the target is on a steady bearing, even with evasive action the target will remain on a steady bearing

Automatic Radar Plotting AidsThis is a computer attached to a Radar which able to automatically measure ranges and bearings of selected targets. From a series of ranges and bearings a track history can be formed:

True track True speed CPA TCPA

Remember the ARPA shows you what the target has done NOT what it is doing now.

Automatic Identification System

AIS is a shipboard broadcast transponder system operating in the VHF radio band. It is designed to send the following information out:

Ship Identification Position Heading Ship length, beam, draught Hazardous cargo

Each AIS system consists of: 1 VHF transmitter 2 VHF receivers 1 VHF DSC receiver Standard marine electronic communications link to shipboard

display systems Positioning and timing information is taken from either an

integral GPS or and external one with a DGPS for coastal navigation

Each system transmits and receives over two radio channels to avoid interference problems

The AIS transponder is usually working continuously whether it is near shore or mid ocean.

Requirements All passenger ships and cargo ships of 300GT or more Ships constructed on or after 1 July 02 must have themShips built before then are to be phased in as follows:

Pax and tankers By 1 Jul 03Other Vessels 50000Gt+ By 1 Jul 04Other Vessels 10 – 50000GT By 1 Jul 05Other Vessels 3 – 10000GT By 1 Jul 06Other Vessels 300 – 3000GT By 1 Jul 07

Electronic Charts

Constructed using either Rasta Data or Vector Data

Raster Data: Produced from scanning the master components used in the

production of a paper chart The resultant image is made up of coloured pixels It is basically a scan of our normal charts

You can not interrogate the objects on the charts to produce information on it

Vector Data: Produced by giving digital values to each and every object on

the chart The computer can identify these objects It is therefore possible to interrogate these objects to obtain

information on them You are able to customize views as well due to the layering

effect given

Display systemsThere are two basic groups:

ECDIS – Electronic Chart Display and Information System RCDS – Raster Chart Display System

ECDIS is a navigation information system which compiles with IMO performance standards and which with adequate back-up arrangements can be accepted as complying with the up to date chart required IMO. The regulations state that you should be using Vector charts but as you can use Raster charts if there are no suitable vector charts available.

RCDS should only be operated together with an appropriate folio of up to date paper chart. There is no performance standard set out and therefore RCDS is unable to meet the requirements listed under SOLAS V/20, 2001 and is therefore not a legal equivalent to and an up to date paper chart

NAVTEX

This is a navigational telex service broadcasting safety messages on 518kHz It is possible to receive Navtex on radio telex but you should really use a dedicated system which comprises of the following:

Receiver tuned to the broadcast frequency Printer and cash roll paper

A microprocessor control ensures that a routine message already received will not be reprinted on subsequent transmissionsYou are able to select services according to the user’s preference but the following services are permanent:

Navigation Warnings Meteorological Warnings

SAR information

Echo Sounders

An echo sounder sends short pulses of ultra sonic sound vertically downwards from the vessel. When it is reflected off the sea bed it returns to the transmission source. The time taken for the sound to return to the ship is measured and with the knowledge of the speed of sound in water is converted into a depth.So basically an echo sounder is a time measuring device.

A trigger fires the pulse generator producing an electrical pulse 10kHz – 250kHz

Part of the pulse is sent to the recorder / visual display producing a mark on the paper or a blip on the screen

Part of the pulse is sent to the transducer where it is converted from AC to Ultra Sound and is directed in a beam to the sea bed

The sound is bounced off the sea bed The returning signal is received by the transducer and is

converted back to an AC current An amplifier boosts the returning signal, which is much weaker

than the transmitted signal A voltage is applied to the recorder or to the display painting a

new trace The depth can be read off the scale

Possible ErrorsStylus Rate ErrorThe speed of pen arm or the belt being incorrect not synchronizing with the transmissions. If the belt is too fast the depth recorded will be too great

Index ErrorWhen the transmission or zero mark is not zero.

False bottom ErrorFalse bottom readings may be obtained when the depth of water is such that the time taken for the returning echo is greater than the time taken for the pen to one or more revolutions and the next pulse has been transmitted

Multiple EchoesThese occur when the pulse bounces between the sea bed and the keel or the sea surface, this will give multiples of the true depth.

Cone Effect

The transmission from the transducer is approximately conical shape this shape reduces the loss of returns due to rolling and pitching, but it can lead to incorrect readings when the bottom contour shelves steeply.

Side Echoes These may be from an object not immediately below the vessel but whose slant depth is less than the depth of water. This is due to side lobes from the transducer and may occur in dredged or man made channels, when the echoes return from the walls before the bottom.

Separation ErrorWhen different transceiver and receiver transducers are used. When in shallow water the limit with the vessel almost aground the depth recorded would be half the distance between the TX and RX transducers. AerationWhen the transmitted pulse encounters air bubbles up to 99.9% of the energy is reflected – it is therefore essential to position the transducer in a position where the transducer is not going to be effected by bubbles e.g. not the bow or stern.

Task – Revision Notes: Magnetic Compass

General

All ships over 150 GRT must be fitted with a magnetic compass, they must also carry a spare compass. This spare should be stored away from the bridge so it is unaffected by any casualty disabling the bridge. It is the owner and Masters responsibility to ensure the compass is in good working order.

Adjustments

The compass should be adjusted when:

They are first installed They become unreliable The ship undergoes structural repair or alteration Electrical or magnetic equipment is installed or removed close to

the compass A period of 2 years has elapsed since the last adjustment and a

record of deviations has not been maintained or such deviations are excessive

Changes in Magnetism during the life of the ship

Masters should check the performance of the compass if

Carrying cargoes with magnetic properties Using electromagnetic lifting appliances to load or discharge Major collision or electrical discharge When the ship has been laid up for a period of time

Monitoring

Compass errors should be determined after each large alteration and at least once a watch. A person holding a certificate of competency as compass adjuster must make any adjustments. If the master deems it necessary a person holding a Masters licence may make adjustment.

Deviation card

Deviations at points around the compassPosition of fore and aft magnetsPosition of athwartships magnetsSize of the flinders barPosition of Kelvin spheres from centrePosition of heeling magnetsCoefficient BThe fore and aft component of the ships permanent magnetism is known as Force P. It effects the compass needle by attracting it forward (if does this then the ship has a magnetically blue bow for this example)

The ships head in the diagram is the compass heading, therefore the north seeking compass needle is always vertically upwardsThe completed diagram shows that the deviation caused by the P force takes the form of a sin curve and produces Easterly deviation on Easterly courses and Westerly deviation on a westerly course

C rod The c rod is the component of the ships vertical soft iron that has an effective upper pole on the compass position. This is induced magnetism and is dependant on which hemisphere you are in. The C rod is usually the ships funnel as the heat coming out of the funnel creates induced magnetism. As with the P force we see that deviation varies as the sin of the course

C rod diagram

Coefficient C

The solitary cause of the cosine component of the deviation is force Q and is due to athwartships permanent magnetism. It is considered positive if it attracts the compass needle to starboardThe diagram shows that the deviation caused by force Q takes the form of a cosine curve. It causes westerly deviation on Northerly courses and easterly deviation on Southerly courses The deviation will increase with magnetic latitude. This is corrected by the athwartships magnets.

Coefficient DThis deviation is the result of a combination of fore and aft and athwartships soft iron. It occurs on the inter-cardinal headings. The Soft iron spheres are used to cancel out this magnetism

Therefore: Coefficient B is caused by force P and the C rod

Corrected using the Flinders bar and the fore and aft Magnets

Coefficient C is caused by force Q Corrected using the Athwartships Magnets

Coefficient D is caused by a combination of fore and aft and athwartships soft iron magnetism

Corrected using the soft iron spheres

Why may there be some deviation left in the compass after it has been adjusted?The compass adjuster can only estimate how much soften iron there is effecting Coefficient B so therefore he may have balanced the amount of flinders bar and the fore and aft magnets correctly for the position the ship is in. If the ship then proceeds over the equator the induced magnetism changes, if there is excessive deviations on Easterly or Westerly headings then we can assume that the compass adjuster got the amount of induced magnetism wrong using the wrong length of Flinders bar. You could adjust the fore and aft magnets to resolve this problem, or you could take regular errors noting down the different deviations, and then present these to the compass adjuster on your return. This is known as a split B problem due to the split between Permanent and Induced Magnetism.

What is retentive error?This is the resultant magnetism that a ship will acquire if on a heading for a prolonged period – for example when tied up alongside for any time. This error is not permanent and will disappear gradually over a few days. This should be noted when leaving port.

Suppose you were on a ship going from Southampton to the Far East, what adjustments would you make to the compass, if any?

Adjust the Heeling Error Bucket as magnetic latitude changes

What is Heeling Error? Deviation caused by the heeling (rolling) of the ship

What would you do if the spheres had been removed from the compass?

Check deviation card, marks on frame, etc.

What routine maintenance would you do on the compass? Visual inspection, check no bubbles, verify position of

correctors, keep record of compass errors.

On what heading is heeling error most noticeable? North or South

What scenario would require spheres placed in the fore and aft line?

Presence of coefficient E. Deviation caused by induction in the ships diagonal horizontal soft iron.

What preparations would you take into consideration before performing a compass swing?

Funnel at normal sea going temperature Upright Vessel Compass card tested for friction Lubber Line coincident with fore and aft line Azimuth prism aligned Position of all deck equipment at normal sea going

condition Ships in vicinity more than 0.3M distant Steady on each heading to prevent guassin error

Task – Revision Notes: Chart work

Clearing BearingClearing bearings must be so far from the Limiting Danger Line that if crossed the bow / stern of the vessel will still be in safe water.

Limiting Danger LineThis should have additional safe water depth built into the depth so that if you were to stray across it you would not go aground.

Clearing bearings / linesClearing marks are selected objects that when in transit or just open lead clear of a danger.

When a clearing line is not available then you can use clearing bearings.

As long as the bearing of the church is not less than 260º and not more than 272º your vessel is clear of the danger.

Advance and TransferAdvance = The amount the vessel has advanced along the original course after the wheel over point has been reached

Transfer = The amount the vessel has moved in right angles to the original course after the wheel over point has been reached.

To use Advance and Transfer you have to use the tables provided by the builder, they are worked out for different speeds and rudder angles.

NLT 260º

NMT 272º

Find Tidal Stream A ship steering 110º at 10kts departs from Position A at 0100 arrives at B at 0200, find the tide experienced during this period.

A - 0100

B - 0200

COG and SOG

Running Fix The vessel below is steering a course of 110º at a speed of 10kts

Tide experienced, Speed is over 1hr in this case

10Nm long

0900 DR

0930 DR

0900 DR

0930 position

Transfer the 0900 5nm up the course line

Things to remember to put on the chart Limiting danger lines Clearing lines / bearings Advance and transfer Wheel over points ETA’s at wheel over points Transit / compass errors SBE time Call master times Astern propulsion check Contingency anchorage VHF channel for pilots / VTS Expected visible ranges Clear anchors PI’s Expected tidal stream Leading lights

Task - Revision Notes: Weather

Low / DepressionA low is an area of atmospheric pressure lower than its surroundingsA low may be referred to a cyclone.

HighA region of higher atmospheric pressure to that of its surroundings A high may be referred to as an anticycloneA ridge is the horizontal extension of the high away from its centre

FrontsZones of bad weather connecting with low pressure regionsCold fronts – bring cold air, good visibility and showersWarm fronts bring warm air, poor visibility and showersOcclusions are where cold and warm fronts merge, from this you get variable weather.

The Atmosphere The doldrums

At the equator there is a low pressure belt around the earth, the air at this point rises to great height because it is strongly heated by solar radiation, the air particles will also hold a lot of water.

Horse LatitudesThe air continues to rise until it hits a ceiling at about 15-20km up – the air then moves pole-wards as it moves northwards it cools and becomes denser therefore it starts to sink. This occurs right round the earth and is called the Subtropical high pressure belt.

Trade windsThe air which has descended in the Subtropical belt has to go somewhere so it forms part of the trade winds. From 20º - 40º N the air flows back into the equator in a layer close to the earths surface, completing the circulation.

Polar HighAt the pole there is an area of cold slow moving air. The pressure is generally much higher than the other latitudes due to the air being very cold and dense.

WesterliesFrom the North the Polar air moves south assisted by the centrifugal effect. Forcing against this is the air mass from the subtropical belt of high pressure. This resists the spread of polar air causing unsettled weather within the air mass due to the two air masses pushing forward against one another. This is called the westerlies belt.

Wind Wind is air in motion If there is a steep gradient – isobars are close together = fast flowing air If there is a gentle gradient – isobars are far apart = slow flowing air

Coriolis The Coriolis force does not move air it only deflects particles as soon as they start movingIf there was no Coriolis force air would move high to low by the shortest route, Coriolis causes the air to rotate.

Northern Hemisphere rotates anticlockwise about a low rotates clockwise about a high

It is the other way round in the Southern Hemisphere

At the equator Coriolis is Nil and the air flows directly from high to low At the poles Coriolis is at its highest deflecting air which wants to obey the pressure balancing force – this therefore prevents balancing highs and lows: this means that the closer a low or high gets to the pole the longer its life is.

Formation of a cold front

When cold air pushes underneath warm air, the warm air must move upwards. Because the air is forced up fairly quickly the result is the formation of clouds – Cumulus

Signs of a cold front passing

Ahead of front In front Behind frontCloud Low continuous

StatusNimbostratus & some Cumulonimbus

Cloud separating

WX Fog & rain Hvy Rain and Thunder

Isolated showers

Wind Dir & Spd Constant

Dir variable / gusty

Veers 180º weakening

Temp Constant Falling Falling rapidly Humidity High Falling Dry air Visibility Mod – Poor Mod – Poor Good – v goodPressure Falling Steady Rising

Formation of a warm front When warm air displaces cold air, it slides over the top of the cold air, the result is the formation of layer clouds – Stratus

Signs of a warm front passing

Ahead of front In front Behind frontCloud Developing

cirrus Cloud all over nimbostratus

Clouded all over stratus or

stratocumulusWX Halo around sun

/ moonRain increasing then stopping followed by fog or mist

Fog patches & drizzle

Wind Increasing and backing

Freshening veering

Dir + Spd constant

Temp Rising Rising ConstantHumidity Increasing V high HighVisibility Worsening Poor ModPressure Falling steadily Falling slowly Steady then

falling

Depressions often form on a front on the boundary of two air masses ‘warm & cold’A depression appears on the chart as a series of isobars around a center point of low pressure.Depressions give unsettled weather and will often be accompanied by strong windsMain direction of movement for a depression is east in the Northern hemisphere.They travel at varying speeds although a larger decaying depression will most likely be slower.

Fog Fog is caused by air being cooled to its dew point (the point where air becomes saturated by the water vapour within it) the condensation of this water vapour produces fog.

Advection / sea fogWhen warm moist air flows over a cold sea, the air is cooled to its dew point and advection fog occurs.It is often only a small thin layer and mast tops can be seen over the top of it.In temperate / high latitudes advection fog is most common in spring when the sea is at its coolest.It is particularly prevalent where prevailing winds transport warm moist air over areas of cold water or major cold water currents.

Frontal fogThis may occur on warm front /occlusion if the temperature of the air in front of the front is very lowFrontal fog occur due to the mixing of warm and cold air on the two sides of the front

Arctic Sea smokeThis occurs in very high latitudes when cold air is blown over relatively warm sea. Evaporation occurs but the cold air is unable to hold the water vapour, so some of the water vapour condenses causing fogUsually found in gaps in ice fields / glaciers

Radiation FogRadiation fog occurs over low lying land on clear nights. It is due to cold air meeting relatively warm land

How to forecast fogWarnings of fog can be observed by frequent monitoring of the wet and dry bulb thermometers. It should be closely monitored whenever the air temperature is slightly higher or almost equal to that of the sea. You should plot temperature against dew point. If the curves converge then you can expect fog

Land and sea breezesBest known in tropical and subtropical climates. It occurs when there is unequal heating of the land and seaBy day the sun raises the temperature of the land but the sea temperature stays very much the same.Air in contact with the land rises very quickly expanding as it rises due to the heating. The air from the sea flows into the gap and takes its place this creates an onshore wind.

Offshore windAt night the air over the land cools rapidly, causing it to become denser and thus it starts to fall, this creates a pressure gradient causing air to flow out towards the sea

These land / sea breezes will be increased if: The sky is clear Calm conditions Desert or dry barren coastline High ground near the coast.

Katabatic windA Katabatic wind occurs when radiation on a clear night causes cooling over sloping ground, the colder denser air will flow downhill producing a down slope wind.

Tropical revolving storms

The requirements for a TRS are: Unstable air

High sea temperature High Humidity Low wind sheer Latitudes higher than 5º so that there is an adequate

Coriolis force

The approach of a TRS may be indicated by: Rapid drop in pressure, more than 3mb below the seasonal

average, Increasing wind speed Change of wind direction High (cirrus) clouds becoming Cirro-Stratus, Cumulus, and

then Cumulo-Nimbus Long low swell from the apparent direction of the storm

centre

If you believe there is a TRS nearby you can work out where your vessel lies in comparison to the eye easily by:

Stop the vessel to find out the true wind speed and direction

Use Buys Ballots Law to estimate the storms centre – The observer should face the wind, the centre of the storm will be approximately 90° to the right of the observer in the Northern Hemisphere.

A rough distance of how far the storm is away from you can be worked out by the wind force – Force 7 = 150nm from the eye

Force 8 = 125nm from the eyeForce 10 = 75nm from the eye

Action to take in the Northern HemisphereIf the wind is veering you are in the dangerous quadrant of the storm

Proceed at full speed Put the wind 10 – 45° on the stbd bow As the wind continues to veer alter to stbd with it

If the wind is backing then you are in the navigable semi circle of the storm

Proceed at full speed Put the wind on the stbd quarter As the wind continues to back alter to port with it

If the wind is steady then you are in the path of the approaching storm Proceed at full speed Put the wind on the stbd quarter and head into the navigable

semi circle Once you are well into the navigable semi circle alter course to

port with the wind as it backs

Action to take in the Southern Hemisphere

If the wind is backing then you are in the dangerous quadrant of the storm

Proceed at full speed Put the wind 10 – 45° on the port bow As the wind continues to back alter to port with it

If the wind is veering then you are in the navigable semi circle of the storm

Proceed at full speed Put the wind on the port quarter As the wind veers alter to stbd

If the wind is steady then you are in the path of the approaching storm Proceed at full speed Put the wind on the port quarter and head into the navigable

semi circle Once you are well into the navigable semi circle alter course to

stbd with the wind as it backs

If your ship is a situation where it can not out run the TRS then you should heave too. In the northern hemisphere put the wind off the stbd bow and in the southern hemisphere off the port bow. Adjust the engine speed so that the vessel is able to maintain steerage way but no more.

Veering = Clockwise Backing = Anti ClockwiseUk Air masses

AM = Arctic Maritime air Cold dry and stable Warming as it travels South, humidifying and becoming less

stable Resulting in Cold and rain

PC = Polar Continental air Cold dry and stable Warming with some humidification over the north sea becoming

less stable and getting warmer Resulting in cool / cold, dry / showery weather

TC = Tropical Continental air Warm dry and unstable Starts to cool therefore no humidification, stabilizing Resulting in warm and dry

TM = Tropical Maritime air Warm humid unstable air As it moves it cools and becomes saturated stabilizing Resulting in rain and fog

PM = Polar Maritime air Cold humid stable air As it moves it warms and the humidity will increase becoming

less stable Results in cool wet weather

Currents The surface and subsurface effect of wind in the generation of ocean currents

Surface Wind blows over the water Friction transfers energy to the water The water initially moves in the same direction as the wind

but Coriolis deflects the water to the ‘right in the Northern Hemisphere’

The surface current speed is 1/40th of the wind speed The surface current direction is 30º from the wind direction

Sub surface effect Surface layer transfers energy to the next layer down As the energy moves down to the next layer it is deflected by

Coriolis The speed decreases due to the viscosity The next layers follow a similar pattern but the direction

keeps changing the further down you go due to Coriolis, this continues until the direction finally becomes negative, this occurs at approx 50m

Ice Accretion

Fresh water ice Forms at temperatures below 0ºC Due to rain, snow, sleet, fog Causes a problem by freezing to aerials, GPS antennae,

Radars o It will cause a Radar to turning (therefore keep it on

when in cold climates)o Settles on GPS antennae and will weaken the signal

Salt water ice Forms at temperatures below -2ºC Due to wind creating spray (in excess of Force 6 required) It freezes on the foredeck Causes listing, change of trim – possible hogging, decreases

freeboard Increases KG Decreases GM

What can be done? Alter course Decrease speed Seek shelter Head towards warmer latitudes

The process of freezing water and the effect of salinity

Cold air -10ºC Cold surface water Density of the water increases Convection brings warm water to the surface At 4ºC the Fresh water reaches its maximum density Cools further, density decreases Convection stops in fresh water, convection carries on in salt

water Fresh water surface looses heat and starts to freeze when the

temperature reaches 0ºC Salt water continues to cool until it reaches -2ºC when

convection stops and the surface starts to freeze

Life cycle of North Atlantic Icebergs

Ice bergs are mainly formed from the glaciers of Greenland

East coast bergs are swept south by the east Greenland currentWest coast bergs are swept north by west Greenland current

Easterly Bergs When they are calved into the sea they immediately start to

break up Very few bergs survive past the south tip of Greenland as they

melt in the warmer water and are broken up by wave action

Westerly Bergs Calved from the westerly glaciers they are swept north and

freeze in the sea ice during the winter in Baffin Bay In spring the ice thaws and the bergs are released Carried south by the Canada and Labrador currents As they get further south they melt quicker due to the sea

temperatures increasing Very few reach the shipping lanes The ice limit is 40N 40 W

MonsoonsSummer over South China Sea

Land gets hot over the desert due to the low specific heat Land is hot so the air heats up Density decreases Low pressure over the land High pressure over the South Indian Ocean Pressure gradient South to North Coriolis Effect deflects flow right in the Northern Hemisphere =

SW Monsoon Coriolis Effect deflects flow left in the Southern Hemisphere = SE

Trades Hot humid equatorial / tropical maritime air which is unstable Orographic uplift causes heavy rain on the windward coast and

where it comes into contact with the mountains

Winter over South China Sea

Clear, cold and dry stable air Land cold, air cold and dense Pressure high over land Pressure low over the equator Pressure gradient North to South

Winds North to South Coriolis deflecting to the right creating the NE Monsoon

The polar Continental air mass gives low temperatures and low humidity

The currents of the North and South Atlantic

Equatorial currents are propelled west by trade winds North Equatorial currents are propelled by the NE trades South Equatorial currents are propelled by the SE trades

Due to the low latitude i.e. on the equator Coriolis is not effective so the current flows straight

As the equatorial currents flow west they meet the continental barrier, this causes a high level to occur and a gradient to exist west to east

Gradient currents flow eastwards because of no Coriolis it flows straight hence the counter current.

Mediterranean Currents

The med gets high levels of sunshine with hardly any rain The imbalance between evaporation and rain lowers the level

and a gradient is formed Surface water flows east through the Gibraltar Straights This surface current is deflected by Coriolis causing the water to

flow anti clockwise around the Med Because of the amount of evaporation the water is much more

salty resulting in denser water

At the Gibraltar Straights density pressure exists at low level so deep water moves west (Think Submarines in the 2nd world war)

Task – Revision Notes: Synoptic Charts

Wind direction From High to Low pressure Deflected to the right in Northern Hemisphere Deflected to the left in the Southern Hemisphere Crossing the isobars at the angle of indraft towards low

pressure roughly two points The depression is – face the wind and the depression is on the

right in the N’ hemisphere The depression is – face the wind and the depression is on the

left in the S’ Hemisphere

Wind Speed Geostrophic wind scale on UK charts Wind speed factors for other charts

Gradient Wind Supergeostrophic around anticyclonically curved isobars Subgeostrophic around cyclonically curved isobars

Surface windTwo thirds of Geostrophic / gradient wind over waterOne third of Geostrophic / gradient wind over land

System movementDepressions move in the direction of Geostrophic wind in warm sectorFronts move in the direction of the wind component perpendicular to the front

Large anti cyclones move very slowly if at allA ridge between depressions moves with the adjacent depressions

Cloud and precipitation

Cloud is generally ahead of warm fronts and behind cold frontsPrecipitation is generally close to the front

Weather RoutingWeather routing services can be found on the web or in Admiralty List of Radio Signals Vol 3

Task – Revision Notes: Chain RegisterThe chain register is a record of all the testing done on all of the Ship’s lifting gear connected with cargo work

Derricks – their fittings, their attachment to decks, the masts etc…

The mate keeps the register and records in it: All tests All replacements made Usually the test certificates are kept with the register All certificates and inspections of all the wire ropes

The register comes in 4 parts:Part

1. Covers the annual and quadrennial inspections and thorough examination of derricks and permanent attachments to the derricks, masts and decks. The annual inspection is carried out by ships personnel and the quadrennial inspection is carried out by a surveyor.

2. This covers the annual thorough examination of cranes, winches, hoists and accessory gear. This is usually provided by the Chief Engineer

3. This covers the annual thorough examination of gear exempted from Annealing which include: Gear made from malleable cast iron, mild steel and any items having case hardened parts or ball bearings and parts of pulley blocks.

4. Record of the annealing of Chains, Rings, hooks, shackles and swivels - ½” or less are annealed every 6 months and over ½” every 12 months

At no time should any attempt be made to lift weight s in excess of the safe working load of the weakest part of the gear unless for a proof load

Regulations require the SWL to be one fifth of the breaking strain

The SWL of various material are below: 3 stranded manila 2d2/1800 3 stranded polypropylene 3d2/1800 3 stranded terylene 4d2/1800 3 stranded nylon 5d2/1800 Flexible steel wire rope 2OD2/3000 Grade 1 chain 2OD2/3600

Task – Revision Notes: Code of Conduct

The code of conduct is a set of rules for us to follow while we at sea, it is there to give us discipline as is designed to help us improve an individuals performance.

Paragraph 9This covers acts of misconduct which if proved with reasonable satisfaction are dismissible offences either immediately or at the end of the voyage. The offences it covers are as follows:

Assault Willful damage to the ship or any property onboard Theft or procession of stolen property Possession of offensive weapons Persistent or willful failure to perform duty Unlawful possession on distribution of drugs Conduct endangering the ship or persons onboard Combination with others at sea to impede the progress of the

voyage or navigation of the ship Disobedience of orders relating to safety of the ship or any

persons onboard To be asleep on duty or fail to remain on duty, if such conduct

would prejudice the safety of the ship or any person onboard Incapacity through the influence of drink or drugs to carry out

duty to prejudice the safety of the ship or those onboard To smoke / use a naked light or an unapproved electric torch in

any part of a ship carrying dangerous cargo or stores where smoking or the use of naked lights or unapproved torches is prohibited

Intimidation, bullying and / or interference with the work of other employees

Behaviour which seriously detracts from the safe working of the ship

Conduct of a sexual nature or other conduct based on sex affecting the dignity of woman and men at work which is unwanted, unreasonable and offensive to the recipient

Behaviour which seriously detracts from the social wellbeing of any other person on board

Causing or permitting unauthorized persons onboard the ship whilst at sea

Repeated commission of breaches of a lesser degree listed in Para 11. after warnings have been given in accordance with the procedures in Para 10.

Paragraph 10Breaches of a lesser degree of seriousness may be dealt with by:

Informal warning given at an appropriate level lower than that of the master

Formal warning by the head of department which will be suitably recorded

Formal warning by the master recorded in the ships official log book

Written reprimand administered by the master and recorded in the official Log

Paragraph 11Offences which are suitable for the procedures outlined in Para 10. are:

Offences of the kind described in Para 9. which are not considered to justify dismissal

Minor acts of negligence, neglect of duty, disobedience and assault

Unsatisfactory work performance Poor time keeping Stopping work before the authorized time Failure to report to work without a satisfactory reason Absence from the place of duty or from the ship without leave Offensive or disorderly behaviour

Dealing with breaches of the codeA seafarer which breaks the code will first be seen by an officer designated by the master. If the officer is satisfied that no further

action is required / no more than an informal warning is required the matter will be dealt with then be regarded as closed.

If it is a more serious offence or it is not the first time it has been commited a formal warning will be given recorded. The case may be referred to the Master, any case falling under Para 9 MUST be referred to the master

A serious case that the master is required to deal with must be done with the minimum amount of delay. The master must give the seafarer the chance to admit that he has done something and allow the seafarer to call any witnesses which may help the seafarer.After careful and thorough investigation and having considered all evidence the master will orally inform the accused of whether or not he finds him guilty of the alleged breach.

The seafarer shall be given a copy of all entries made in the logbook relating to his breach and shall acknowledge this by receipt. He shall be given a copy of any report made to the company which relates to the incident for which the seafarer is subject to disciplinary action .

Task – Revision Notes: Code of safe working practices

The code is concerned with improving health and safety on board ship. The code provides guidance on safe working practices for situations that commonly arise on ships. It is a statutory requirement for the code to be carried on UK ships

Section 1 – Safety responsibilities and shipboard managementChapter 1 – Risk Assessment – Who, what howChapter 3 – Safety Officials – Officer, reps, committeeChapter 4 – Personal Protective Equipment Chapter 6 – Means of access and safe movement – pilots,

Section 2 – Personnel Health and SafetyChapter 8 – Safety Induction - proceduresChapter 10 – Emergency procedures – musters and drillsChapter 11 – Security onboard – piracy, drugs, terrorismChapter 12 – Safe movements – WT doors, lighting

Section 3 – Work ActivitiesChapter 16 – Permit to work -Chapter 17 – Enclosed spaces – hazards, proceduresChapter 18 – Boarding Arrangements – positioning, lighting, netsChapter 21 – lifting plant – use of equipment, hand signals

Chapter 25 – Anchoring, Mooring & Towing

Section 4 – Specialist shipsDry cargo, tankers, Offshore, Ro-Ro, tugs

Task – Revision Notes: Health and Safety

Employers must provide workers with all the appropriate health and safety items taking into the risks to their health and safety.

On every ship with more than 5 crew a safety officer must be appointed

The point of the safety officer is to take an independent view of safety on behalf of the company, although it is recognized that sometimes the safety officer has other duties such as being chief officer and may well need to conduct risk assessments also.

Safety Representatives must also be elected, these crew members must have more than 2 years consecutive sea service since attaining the age of 18

A safety committee should be established

Safety Inspections The safety officer should make an inspection of each accessible

part of the ship at least once every three months. Records must be kept of all inspections

Accidents The safety officer should maintain a record of all accidents and

dangerous occurrences

The investigation of incidents is very important and must be done as required by MSN 1584

Interviews should be carried out to try and determine what went wrong / what happened

Statements should be taken, these should try and cover the facts rather than opinions

Records should contain:o Details of the incident o Dateo Persons involvedo Nature of injury o All statementso Recommendationso Any action taken

In addition it should contain: List of witnesses, addresses, positions and

occupations Whereabouts of original signed statement Date accident reports were sent to the MAIB List of items collected, why and where stored Index

Personal protective equipment PPE must only be used when risks cannot be avoided or reduced

to an acceptable level by safe working practices that cause no health risk to any worker

It is the employers responsibility to ensure workers are provided with suitable PPE

And should be supplied at no cost All workers required to use PPE should be trained in its proper

use, and must wear the equipment every time they are performing the task that it was supplied for

Safety Signage Safety signs should be used whenever a hazard or obstruction is

present. Employers should ensure that safety signs are displayed where

appropriate Workers should ensure they understand the signage before

starting any work and

Means of Access The master and the employer must ensure that a safe means of

access is provided between the ship and shore

When the access is provided by the port then it is still the masters responsibility to ensure that the equipment meets the requirements

Task – Revision Notes: Customs, Heath and Immigration

Customs on Arrival All vessels arriving from outside the European Union must report

to customs Vessel arriving from within the EU that are not on an authorized

regular shipping service – which is a service is one that operates between EU ports on a regular service – these ships shall report to customs

The report to the customs house must be made within 3hrs of arrival

If there are Pax onboard then the master must inform the customs before arrival that they were disembarking

Pax which are not EEA citizens must get the immigration officers approval before disembarking

A customs officer will usually compare the contents on the bonded locker with the list of ships store, if everything is in order he will seal the locker until the ship departs

To obtain clearance the following documents must be completed

General Declaration Ship stores declaration Crew effects declaration Crew list Pax list if there are Cargo Declaration

Customs on Departure All vessels leaving a UK port for a destination outside the EU or

for a free zone within the EU must be cleared by customs before they leave

Vessels with a fixed pattern – i.e. Ferries may be granted with a fixed period clearance for specified voyages

To obtain clearance the following documents must be completed General Declaration Crew list Pax list Stores declaration - required if stores are loaded in

the UK Cargo declaration

Health clearance Free pratique means that you are seeking permission to

disembark and commence cargo operations A ship shall seek health clearance if arriving from a foreign port if

during the last 28 days there has been a death – not from an accident, illness where the persons temp is over 38ºC, rash, glandular fever, jaundice or where the person has sever diarrhoea

The master must report any person suffering from an infectious disease, any animals that may spread an infectious disease – e.g. cockroaches infestation

If a ships accommodation needs fumigating guidance can be sort from the IMDG code supplement

Immigration All pax must be listed on a passenger list, they will generally

require a passport The pax may be required to complete a landing card but this is

dependant on how long the ship is going to be in the UK, type of voyage etc…

Task – Revision Notes: Hours of Work Regulations

Under the safe manning, hours of work and watch keeping regulations 1997 all vessels must have a schedule of duties and a record of deviations.

The schedule of duties must describe the work for masters and seamen who’s work includes watch keeping duties. It must also include the chief and second engineer and the mate. This is to provide a guide so that they do not work more hours than is safe for the ship or for their own performance of duty.

The schedule of duties should be displayed in a prominent place in the crew accommodation for the information of all seamen

The schedule of duties must specify the maximum period of continuous watch keeping, the minimum rest period between watches and the total daily, weekly and monthly hours of work.

The minimum periods of rest allowed are:

In any 24-hour period there must be a minimum of 10 hours rest, which may be divided into not more than two periods, one of which must be at least 6 hours.

To provide for a minimum of 10 hours rest in any 24 hour period and 77 hours in any 7-day period and 4 weeks annual paid leave

Exemptions may be made to the above rules in the case of emergencies, drills or overriding operational conditions (conditions where essential shipboard work cannot be delayed for environmental or safety reasons or which cannot reasonably have been anticipated at the start of the voyage)

Where the Master or crewmember has been required to work during a scheduled rest period it must be entered into the record of deviations giving his name and the reason why he worked during the rest period.

A copy of the schedule of duties and record of deviations must be kept by the company and the Master. It should be kept for 5 years and be made available to the MCA or proper officer if requested.

Task – Revision Notes: ISM Code

The purpose of the code is to provide an international standard for the safe management and operation of ships and for pollution prevention.

The Safety Management objectives for the company are: Provide for safe practices in ship operation and a safe working

environment Establish safeguards against all identified risks

Continuously improve safety management skills of personnel ashore and aboard ships, including preparing for emergencies related both to safety and environmental protection

The Safety management system should ensure: Compliance with mandatory rules and regulations That applicable codes guidelines and standards recommended

by the organization, Administrations, Classification Societies and maritime industry organizations are taken into account

Every company should develop implement and maintain a safety management system which includes the following functional requirements:

A safety and environmental protection policy Instructions and procedures to ensure safe operation of ships

and protection of the environment in compliance with relevant international and flag state legislation

Define levels of authority and lines of communication between shore and shipboard personnel

Procedures for reporting accidents and non conformities with the provisions of this code

Procedures to prepare for and respond to emergency situations Procedures for internal audits

Safety and environmental ProtectionThe company should establish a safety and environmental protection policy.

Designated person ashore (DPA)To ensure the safe operation of each ship and to provide a link between the company and those onboard. The responsibility and authority of the DPA should include monitoring the safety and pollution prevention aspects of the operation of each ship and ensuring the adequate resources and shore based support are applied as required

Masters AuthorityThe company shall clearly define and document the masters responsibility with regard to:

Implementing the safety and environmental protection policy of the company

Motivating the crew in the observation of the above policy Issuing appropriate orders and instructions in a clear and simple

manner

Verifying that specified requirements are observed Reviewing the SMS and reporting its deficiencies to the

shorebased management

The company should ensure that the master is: Properly qualified for command Fully conversant with the Company’s SMS Given necessary support so that the masters duties can be safely

performed

Company verification review and evaluation The company should carry out internal safety audits to verify

whether safety and pollution prevention activities comply with the SMS

The company should periodically evaluate the efficiency of and when needed, review the SMS in accordance with procedures established by the company

Personnel carrying out audits should be where possible independent of the areas being assessed

Certification The ship should be operated by a company with a valid

Document of Compliance The Document of compliance is issued by the administration for

a period of 5 years The Document of Compliance is only valid on for the ships

indicated on it There will be annual verification of the Document of Compliance

by the administration A Safety Management Certificate is issued to each ship. It is valid

for 5 years with and intermediate audit carried out between the second and third anniversaries.

A copy of the Document of Compliance is also carried on board. Safety Management PlanThe Safety Management System should include shipboard instructions and procedures covering the following operations: Shipboard Operation: General

Including Standing Orders, Watchkeeping, Security, maintenance, record keeping, passenger control, safety committee

Shipboard Operations: in PortIncluding embarkation and disembarkation arrangements, boarding card systems, cargo operations, handling of dangerous goods, stability, harbour watches, bunkering, storing, re-fit and dry-docks

Preparing for SeaIncluding check-lists, assessment of stability, cargo securing, securing hatches and other shell openings, testing of main engines,

steering and bridge equipment, passage planning, verification of pax and crew figures, positive reports from departments, clearance, safety broadcasts for passengers.

Shipboard Operations: at SeaIncluding watchkeeping requirements, navigation, position fixing, use of navigational aids, look-out, fire rounds, upkeep of log books, drills

Emergencies and ContingenciesCheck-lists for all emergencies and contingencies including General Emergency procedures, fire, collision, man overboard, equipment failure, heavy weather, pollution, passenger control and broadcasts etc.

Task – Revision Notes: ISPS Code

International Ship and Port Facility Security Code Establishes communications between the MCA and shipping and

port industries to detect security threats and take preventative measures

Establish roles and responsibilities between the MCA and shipping and port industries for ensuring maritime security’

Ensure collection and exchange of security related information Provide plans and procedures to react to changing security

threat and levels

The code applies to: All pax ships Cargo ships over 500GRT Mobile offshore drilling Port facilities engaged in international trade

The code requires all vessels to carry a ship security plan, to have a Company Security Officer and designate a person onboard as the Security Office. The code provides guidance to Masters and Security Officers. The plan must be approved by the flag state and is revalidated every 5 years

Ship Security OfficerEvery vessel must have a designated security officer who is accountable to the Master. He is responsible for the security of the ship, monitoring of the security plan and is the ships liaison with the Company Security officer and Port Security Officer. The ship security officer must:

Regular security inspections Raise security awareness and provide training for the crew Report non conformities and deficiencies to the Company

Security Officer Maintain the security plan keeping records and proposing new

modifications to it Liaise with Port Security and co ordinate security measures when

alongside

Company security officerThe company shall designate someone as the Companies Security Officer. He will be responsible for checking and assessing each ships security monitoring the security plan and liaising with the port and ship security officers. He must

Advise threat levels to each ship Ensure ship security audits are carried out Ensure the maintenance and modification of the plan

Ensure that deficiencies and non conformities are promptly addressed and dealt with

Communication and co-operation between Ship security Officer and port Security officer

The masterThe masters responsibility regarding the safety of the ship remains unchanged, he is still able to make decisions and shall not be constrained by the company, this includes denial of access to persons and refusal to load cargo. If a conflict arises between safety and security requirements the master shall give effect to those requirements necessary to maintain the safety of the ship. The master shall implement temporary security measures if he thinks it is necessary.

The government authorityThe authority – MCA is responsible for:

Setting the applicable security level Testing approved plans Surveying vessels compliance and issuing security certificates

The Ship security assessment The process of developing and updating the security plan, it is the responsibility of the Company Security Officer to ensure that the assessment is carried out by a qualified person. The assessment should include:

Evaluating existing security measures Evaluating key shipboard operations that require protection Identification of threats and the likelihood of the occurrence Identification of weaknesses

The assessment should be documented and retained by the company

The Ship Security PlanThe company Security officer is responsible for ensuring that all vessels carry an approved ship security plan. Recognized companies may prepare this planor your behalf. It should include:

Identifying restricted areas and protection for such areas Measures for preventing unauthorized access Procedures for responding to threats and instructions for

governments Procedures for evacuation of the ship Procedures for reporting security incidents Duties of security personnel Procedures for training and drills Procedures for auditing and reviewing the plan

Identification of Ship security officer and company security officer contact details

Instructions and testing of security equipment Locations of ship security alert system activation points and

instructions on their use

TrainingThe company security officer and the ship security officer shall have received training in the contents of the ship security plan. Other personnel involved in security duties should have sufficient knowledge to perfume their task.The ship security officer is to ensure that regular training is carried out and drills carried out at 3 monthly intervals. The Company Security Officer should participate in exercises involving the ship and or government agencies at intervals not exceeding 12 months

Certification International Ship Security Certificate – new ships and old ships

once they have proved they comply with the code Renewal Certificate – every 5 years Intermediate Verification – At least one intermediate survey to

be carried out between the 2nd and 3rd year

Security Levels There are 3 levels and it is the responsibility of the government authority –MCA and applies to ships and port facilities

Security Level 1 – Normal operational levelPorts and ships shall:

Check identity of all persons boarding the shipSecure areas for baggage and car parksSecuring unattended spaces adjoining passenger areasManning access points to the vesselProvide security briefing to ship staffRandom search of baggage

Security Level 2 – Heightened Additional personnel to patrol the deck Limiting access points to the vesselBoat patrols in the waterside of the shipEstablish restricted zones around the vessel on the shore

sideIncreased searches of personnel and baggageAll visitors to have an escort at all timesFull search of the ship

Security Level 3 – Exceptional – Imminent risk of security incidentSingle access to the shipNo access to visitorsSuspension of cargo / embarkation operationsEvacuation of the vesselMoving vessel to secure location or to sea

Ship Security Alert SystemShips built after 1st of July 2004 and passenger vessels and tankers must have an approved ship security system fitted not later than the first survey of the radio installation after 1st July 2004. For all other ships this is extended to 1st July 2006

The alert system shall be able to: Transmit a ship to shore security alert indicating that the security

of the ship is under threat or has been compromised Be activated from the bridge and at least one other location Not send the alert to other ships Not raise any alarm on the ship Continue to transmit until reset

Task – Revision Notes: lifting equipment

The master and the employer must ensure that any lifting plant onboard is:

o Good designo Sound constructiono Fit for purposeo Properly installed o Properly maintainedo Not being used in excess of its safe working load

Systematic preventative maintenance programs should be carried out in accordance with the manufactures instructions

Only trained competent people can use the lifting plant

Testing Master and employer must ensure that no lifting plant is used:

o After manufacture or installationo After any repair of modificationo Should not be used unless it has been suitably tested by a

competent person in the last 5 yearso Should not be used if it has not been thoroughly examined

by a competent person at least once in the last 12 month period

Competent person Should be over 18yrs old and have practical and theoretical

knowledge required. This should include actual experience of the type of machinery or plant concerned sufficient to be able to detect any weakness and to assess their relation to the strength stability and functions of the plant

A thorough examination means a detailed inspection and any such dismantling as the competent person feels necessary to remove any hidden parts that would allow a thorough examination.

All lifting plant must be inspected every 12 months Where the lifting plant is used very frequently more frequent

inspections may be carried out

Markings

The master and the employer must ensure that each lifting appliance is clearly marked with its safe working load and a means of identification

Where the SWL varies with a cranes radius of operation it is required to be fitted with an accurate indicator visible to the driver, showing the radius of the load and the SWL corresponding to that radius

The requirement to mark the lifting gear will generally apply to lifting beams, frames and other gear whose weight is substantial in relation to the loads they lift

Certificates The master shall ensure that a certificate is supplied within 28

days following any statutory test or examination. This certificate must be stored onboard for a period of at least 2

years All reports and certificates should be kept readily available for

dock worker or shore employer using the ships plant A register of lifting appliances and items of loose gear should be

maintained in a form based on the model recommended by the International Labour Organization

Records and reports may be kept in paper or electronic format

Precautions to take prior to a heavy lift Risk assessment Adequate stability for the lift to take place. Increase the GM by

filling bottom tanks and remove any free surface from the tanks Any additional backstays and preventers should be rigged Full inspection of all guys, lifting tackles, blocks, shackles and

wires. All equipment should be within SWL Lift gangway and have sailors standby at the mooring stations Fenders rigged over the side Winch drivers are experienced and competent Remove ships rails Release barges that may be tied up alongside Inspect the load and confirm the lifting points All unnecessary personnel clear Take the weight, as the cargo leaves the dock the ship will heal

over Chief Officer to inspect all the rigging, once happy with

everything then he will hand the ‘con’ over to the hatch foreman

Derrick Survey Every 12 months by the chief officer

Every 5 years by a surveyor, the surveyor will pay particular attention to the fittings on the derrick, mast and deck. He will check fro excessive wear and corrosion

All blocks, shackles, links chains and wire will be examined to ensure they are all in satisfactory condition

Task – Revision Notes: MAIB

The MAIB ‘Marine Accident Investigation Branch’ examines and investigates all types of marine accidents to or onboard UK flagged ships and also UK ships worldwide.

The MAIB’s sole objective when investigating an accident is to determine the cause with an aim of improving the safety of life at sea and trying to avoid similar accidents occurring in the future. The MAIB is not there to apportion liability or blame and does not enforce laws or carry out prosecutions. They carry out separate investigations to those made by for example the police.

What to report to the MAIB? Accidents Major Injuries Serious injuries must be reported within 14days Near miss accidents do not need to report although the MAIB

would recommend for it to be reported so further lessons can be learnt

Statutory Instrument - 2005 No. 881The Merchant Shipping (Accident Reporting and Investigation) Regulations 2005, the purpose of this Statutory Instrument is make it law that the master / senior surviving officer / owner / Harbor Authority / MCA must contact the MAIB after any major accident or serious injury. The report must be sent as soon as is practicable by the quickest means available.

Is a MAIB investigation always required?

Not all accidents or injuries will be investigated by the MAIB, if the ships report and investigation has been well executed then that is often good enough, obviously for a more serious accident an external investigation maybe required.

Task – Revision Notes: Pilot Ladders

Ladder must be secured properly and lie flat on the side of the ship providing access to the ship from 1.5m to 9m

A single length of ladder should be used The treads must be made of hard wood Each tread should be made of wood without any knots Each tread must be not less than 480mm long, 115mm wide and

25mm deep The steps should not less than 300mm nor more than 380mm

apart The steps should be secured in such a manner that the step will

remain horizontal The lower 4 steps shall be made of hard rubber No pilot ladder must have more than two replacement steps The side ropes must be made of 18mm manila rope Hard wood spreaders between 1800 – 2000mm long must be

provided at such intervals as will prevent the pilot ladder from twisting

A spreaders must be fitted not more than 5 steps from the bottom

Spreaders must be fitted at intervals of not more than 9 steps.

Task – Revision Notes: Risk assessment

Risk assessment is the careful examination of what in the nature of operations could cause harmThe aim is to minimize accidents by:

First establish hazards which are present at the place of work Address risks to health and safety of workers Advice on the use of personal protective equipment Assessments will depend on ship types, the nature of operations

and the type and extent of the hazards and risks Process of risk assessment should be simple but meaningful

What to assess? Should cover the risks arising from the activities of workers on

the ship Risks that are reasonably unforeseeable need not be assessed.

Who carries it out? In all cases the individual employers have responsibility for

assessing risks to their workers. In practice risk assessment is a continuous process and should

be done every time before work starts

The main elements of risk assessment are: Classify work activity

Identify hazards and personnel at risk Determine risk Decide if risk is tolerable Prepare action plan if necessary Review adequacy of action plan

Identifying hazards Is there a source of harm? Who or what could be harmed? How could harm occur?

Determine riskThe risk from the hazard may be determined by estimating

The potential severity of harm The likelihood that harm will occur

Once you have determined if there is a risk or not you must decide if it is tolerable or not.

Once the significant risks have been decided upon an action plan should be decided upon

All plans should be reviewed each time they are used to ensure that they cover the specific job and hazard that is being done.

Guidelines can be found in the Code of Safe Working Practices chapter 1.

Task – Revision Notes: Ships’ Certificates

Documents/Certificates for Masters Handover

Solas Certificates Safety Construction (5 years) Safety Equipment (2 years) Safety Radio (1 year) Passenger Ship Safety Certificate (PSSC) (1 year)

Marpol Certificates International Oil Pollution Prevention Certificate (IOPP) (5 years) International Noxious Liquids Certificate (INL) (5 years) IOPP Exemption Certificate

Loadline Certificates Loadline Certificate (1 year) Loadline Exemption Certificate

Other Certificates Tonnage Certificate Certificate of Registry Certificate of Class

Deratting Certificate (6 months) Safety Management Certificate Certificates of Fitness for Type of Cargo, Document of Compliance

for the carriage of Dangerous Goods

Other items Official Log Book Crew List/Crew Agreement Ships Accounts Medical Log Book/Drugs Stability Book ISM Documents (SMS and DOC) IBC Code, BCH Code Charter Agreement Safe Keys/Code Oil Record Book Garbage Record Book

Official Log Book

Sections1. Record of Seamen2. Return of Births and Deaths (RBD1)3. Musters and Drills4. Inspection of Pilot Hoists/Accomodation Ladder5. Draughts/Freeboard (FRE13)6. OLB Entries

Pt IV – Watertight doors

FRE 131. Name 2. Registry3. Official Number4. Freeboard5. Date-Port-Fwd-Aft-Freeboard-Density-FWA-DWA-Signature

Crew Agreement

The ALC documents include the OLB, and the Crew Agreement divided into parts ALC1, ALC1(a), ALC1(b), ALC(c), ALC(d) and ALC6.

They are obtainable from the RSS, the MCA or a Proper Officer (e.g. British Consul).

Once completed (at the closure of the crew agreement) the documents are returned to the Registrar of Shipping in Swansea (RSS).

The ALC Documentsi) ALC1 – The outer card cover in which all the other

documents are fixedii) ALC1(a) – The List of Crew who are party to the crew

agreementiii) ALC1(b) – The List of Crew who are exempted fron signing

the crew agreemment (e.g. Master, office personnel, contracters etc.)

iv) ALC1(c) – List of Young Persons under 18.v) ALC1(d) – The contractual conditions of the crew

agreement and clauses.vi) ALC6 – The crew copy of the agreement, displayed in the

ship for the crew along with a copy of ALC1(d)

Certificate of Registry

1. Name2. Ships details (Official Number, tonnage etc)3. Owners (64 shares in a ship, owner of more than 34 is majority

“owner”)4. Port of Registry/Choice

Safety Radio Certificate

1. List of Equipment2. Trading Limits

Safety Equipment Certificate

1. Fire Fighting Eqiupment2. Life-saving Equipment3. Lights and Shapes4. Magnetic Compass/Gyro5. Signals (Whistle etc)6. Charts and Publications (as listed in Solas, S.I.etc)7. Pilot Ladder and Accomodation Ladder (gangway is part of Safety

Construction Certificate)

Safety Construction Certificate

1. Hull and Machinery

Certificate of Seaworthiness

This is an similar to an Interim Certificate of Class and is given by an uninterested third party (Class 1 Deck or Engine) after repair before a full Class survey.

Loadline Survey

1. Structure2. Watertight Integrity3. Freeboard (draught marks, loadline permanently marked, deck

mark, freeboard)4. Safe Access 5. Watertight Doors/Weathertight Doors6. Deadlights7. Hatches (hose test, watertightness)

8. Shell Doors (indication, watertight integrity, cameras)9. Stability Information10. Ventilators (gooseneck, cowled or mushroom. May have flame

arresters)

Difference between Watertight Doors and Weathertight Doors? Watertight prevents the passage of water in both ditections, weathertight only from one direction (usually into the ship)

Difference between an air pipe and a sounding pipe? The air pipe if at forward end of the tank, sounding pipe is aft.

International Oil Pollution Prevention Certificate (IOPP)

Survey of Ships structure, equipment, systems, fittings, arrangements and materials in respect to the relevant provisions of Marpol Annex 1.

Equipment must be type-approved.

Check of Oir Record Book, manuals, certificates etc.

SOPEP

SOPEP is the Shipboard Oil Pollution Emergency Plan. Its main purpose is to set in motion the necessary actions to stop or minimise the discharge and reduce its effects on the marine environment. It should also contain Reporting Requirements and contact names, addresses and numbers.

Oil Pollution Insurance Cerificate (OPIC)

Carried by all vessels carrying over 2000 tonnes of oil in bulk as cargo.

Insurance cover is provided by P&I Clubs (usually up to $500million) The certificate is provided, once proof of insurance is verified, by MCA in London.

Passenger Ship Safety Certificate (PSSC)

A three-in-one certificate (construction, equipment and radio) issued as a SOLAS requirement for all passenger ships on international voyages.

A Record of Equipment supplements the PSSC, listing details of LSA, FFA, radio eqiupment etc.

The Passenger Certificate (PC) is a requirment for all UK registered passenger ships on international voyages and includes the total number of persons allowed to be carried on board.

The PC may also contain information regarding subdivision marks (C1, C2, as appropriate) and the corresponding passenger and crew figures.

C1 is a one compartment ship, C2 is two compartment. If one or two comartments are bilged, as relevant, the ship should not submerge the Margin of Safety Line (or Margin Line) which is 3” below the bulkhead deck i.e. all watertight bulkheads should extend 3” above the damaged condition waterline.

Task – Revision Notes: SOLAS – Safety of Life at Sea

Chapter 1 – General ProvisionsChapter 2/1 – Construction: structure, stability, machinery, electrical installationsChapter 2/2– Construction: fire protection, detection, extinction Chapter 3 – Life Saving appliances and arrangementsChapter 4 – Radio CommunicationsChapter 5 – Safety of navigationChapter 6 – Carriage of CargoesChapter 7 – Carriage of Dangerous GoodsChapter 8 – Nuclear shipsChapter 9 – Management for safe operation of shipsChapter 10 – Safety Measures for high speed craftChapter 11 – Special measures to enhance maritime safetyChapter 12 – Additional safety measures for bulk carriers Appendix – Certificates

Brief Notes….

Chapter 1 Made up of two parts A & BPart A – Application + definitionsPart B – Surveys and Certification

Passenger ships must have: An initial survey before going into service Renewal surveys every 12 months Additional surveys when required

Passenger ship safety certificates shall not exceed a period of 12months where’s cargo safety certificates shall not exceed 5 years before renewal

Chapter 2/2 This requires

At least 1 hose for each hydrant

Hydrants shall be in a position where there can be 2 jets not emanating from the same hydrant and may reach any part of the ship normally accessible to the pax / crew while the ship is being navigated

In pax ships for each pair of BA sets there shall be 1 fog applicator

Vessels carrying dangerous goods shall comply with the regulations, on compliance the administration shall provide the ship with an appropriate document of compliance of the construction and equipment with the requirements of this regulation

Chapter 3This requires

At least 1 lifebuoy shall be fitted on either side of the ship with a buoyant lifeline equal to and not less than twice the height at which it is stowed above the waterline when the vessel is in the lightest seagoing condition or 30m whichever is greater.

Lifebuoys:Under 60m - 8 required60 – 120m - 12 required120 – 180m - 18 required180 – 240m - 24 required240 + - 30 required

Appendix

Certificates required for ISM – Document of compliance – A Document of compliance shall be issued to every company which complies with the requirements of the ISM code. A copy of the document shall be kept onboardSafety management – A Safety Management Certificate shall be issued to every ship by the Administration or Organisation recognized by the Administration. The Administration or an organisation recognized by it shall, before issuing the safety management Certificate, verify that the company and its shipboard management operate in accordance with the approved safety management system

Certificates required for Dangerous goodsDocument of Compliance with special requirements for ships carrying dangerous goods – An appropriate document as evidence of compliance with the construction and equipment requirements of that regulation

Dangerous Goods manifest or Stowage Plan – Each ship carrying dangerous goods shall have a special list or manifest setting forth, in accordance with the classification set out in regulation VII/2 the dangerous goods on board and the location thereof. A detailed stowage plan which identifies by class and sets out the location of all dangerous goods onboard may be used in place of such a special list or manifest. A copy of one of these documents shall be made available before departure to the person of organization designated by the port state authority.

Task – Revision Notes: Taking over command

When a master arrives at a ship he should when walking up the gangway:

Note the state of the ships side and exterior – including draught marks, rigging of the accommodation ladder & safety Net, visible condition of LSA and FFA equipment this will give him a good indication of the ships management

He would expect at least the following from the outgoing master before he takes over:

He should check his handover notes The current manning levels and compare them with the safe

manning levels The ships condition report The SMS documentation The standard of crew competency and training Any voyage orders Safe combination code!

When the crew and officers are to join after you the master should inspect the following:

All crew have a valid medical certificate All competency certificates are carried in original form and that

they are in date All the crew receive there familiarization training as required by

SOLAS

The master should then discuss the ships operations with the senior management teamNavigation and voyage planning should be discussed with the Navigation officer

The master should sign himself on by completing the white spaces in the ALC(b) noting the reference number on the inside cover of the Official Log BookHe should then:

Enter his name and COC No. on the front cover of the OLB Check the ships documents and cash Write in the narrative section that you have taken over from the

previous officer and that all the documents are in order and have been handed over

Task – Revision Notes: Stowage of Cargoes

Ref: Thomas’ StowageCode of Safe Practice for Cargo Stowage and Securing

Master and crew must exercise due diligence to ensure the ship is seaworthy.

Damage ClaimsClaims may be made for the following reasons:

ChafeDamage occurs due to the to and fro movement from the motion

and vibration of the ship causing the cargo to rub and chafe against each other, against sharp projections and rough surfaces.

Baled goods are particularly susceptible

Temperature Temperature fluctuations may cause condensation or accelerate

deterioration of cargoes.High temperatures may affect cargoes:

Softening of chocolates, fats and coatings Cause partial / full decomposition

Take a commodity up to its flash point – therefore explosive Expansion

Low temperatures may affect cargoes: Freezing of fruits and vegetables Freezing of bottled liquids – can cause bursting Hardening and cracking Separation

Cargoes which are subject to damage due to heating:Should be stowed away from local sources of heat i.e. away from engine and boiler room bulkheads and casingIn the past large claims have arisen due to cargoes literally being cooked on the top of tanks that are being heated.

Ventilation may be required to reduce the effects of heat build up

Damp or wet packages of all cargoes should be carefully examined and if in doubt the cargo should be rejected.

Cargo Mixtures Claims in this class are mostly in respect to bulk grain and seed cargoes. But heavy claims have been given for mixtures of china clay and sliver sand, or oil with ore. To avoid such mixing careful regard should be given to:

Overstowing Separations when different bagged goods are being carried Separation within holds (This is at the Charters expense

and should be written into the charter party.

Dust and StainWhen loading dusty cargoes other cargoes in the vicinity should be well covered, ideally you should load these cargoes first.Packaged cargo at the bottom of the stow in a lower hold may become stained by oil that may have gathered in the hold, this can taint and spoil the cargo. Wooden bulkheads can be constructed to separate the cargoes. Bulkheads should be made of wide planks to reduce the number of seams.

Rust DamageDue mainly to moisture, rain, fresh or salt water. Steel cargoes may suffer irreparable damage if rust occurs. Ventilation may need to be used to reduce any cargo sweat.

Wet Damage Condensation sometimes known as sweat can cause:

Rust Discolouration Mould Caking or clogging

For condensation to occur the two following factors must be available – Source of moisture and a temperature gradient. The source of moisture may come from:

The cargo The packaging The dunnage Air trapped in the hold Any air introduced in the course of ventilation

Discharging fire damaged goodsSuch goods should be discharged under survey they should be divided into separate lots:

1. goods damaged by fire and or smoke2. goods damaged by water or steam used in extinguishing the fire 3. goods damaged broken or otherwise injured in obtaining access

to the seat of firePilferage In order to protect a ship from blame and responsibility for pilferage. Ships officers should organize a close watch on the holds and other cargo liable to be broached. When many holds containing broachable cargo are being worked responsible ships personnel should carefully watch the loading process. Frequent and regular visits by the OOW to the area being worked should be a good deterrent. As soon as possible broachable cargoes should be overstowed and hold watchmen should not been removed until it is no longer possible to get at the broachable goods.

Accurate and reliable tallying should be carried out Sweepings and residue should be removed by responsible

personnel Attractive and high value good should be stowed in appropriate

lock ups or buried into the stow Adequate lighting should be provided Proper instructions for the safe handling of the goods should

clearly marked on the goods Contents identification and advertising should be avoided Tamper proof seals should be used Correct documentation should be provided Strapping and securing should be suitably strong

Rats and MiceRat guards must be fitted to all mooring lines In the interest of health rat fumigation of holds and accommodation is at times essential.Ships must carry a valid De rat certificate which is issued by a competent authority every 6 months.

Cleaning and FumigationCompartments and containers which have been empty of cargo must be made suitable for the reception of the next load by being thoroughly cleaned. Where evidence of an infestation exists the hold may have to be fumigated. Normally this is done by a shore side team although ships staff may use smoke fumigants. Some grain cargoes come with fumigants in them in the form of white pellets – these should not be touched or approached – they produce phosphene gas when they react with the moisture in the atmosphere. It may be decided to fumigate the cargo upon completion of loading, if this is the case it may be necessary to evacuate the ship. The master should follow the instructions very carefully.

RegulationsMost countries have very strict quarantine regulations to prevent the import of unwanted vermin. These regulations usually prohibit the importation of timber with any bark still attached and timber entering the country has to be specially treated.

Mechanical DamageLowering heavy slings of cargo into the hold too fast may be responsible for damage to the cargo. Dragging cargo out at the time of discharge may result in damage. Use of cargo hooks on bags, packages, paper, furs etc… should be prohibitedCrow bars may also be used when breaking out cargoes but it should be prohibited when breaking out cargoes not designed to be handled in such a way.Try to use the correct equipment for the job at all times.

SweepingsThis refers to the original contents of a cargo which has been spilt. If second hand bags have been used to hold the cargo then this will have been endorsed on the Mates Receipt and on the Bill of Lading.Torn or damaged bags do not come under sweepings and should be repaired and put with the rest of the cargo. To avoid the ship getting the blame for any sweepings that occur ashore after discharge the ships sweepings should be bagged and tagged, weighed and delivered as such. By getting a receipt there is no

chance that the ship will be blamed for any damage done out of there control – this will reduce claims against the ship.

Receiving CargoesIf goods are delivered in an unsound condition then they cannot be delivered in a sound condition either therefore a careful watch should be made during loading to ensure that no, damaged, stained, torn, leaky, repaired etc… goods is loaded.

Mates Receipt The mates receipt is a receipt of the goods actually received onboard.It is often the ship owners first line of defense in defending a cargo claim. It is therefore essential that the receipt are issued accurately and reflect the true condition of the cargo. If there is a dispute over the amount of cargo loaded then the smaller of the amounts should be recorded with a clause saying that there may be an extra such and such amount of cargo.On a bulker it might be impossible to do a draught survey to compare the draughts with those supplied by the shipper. The mates receipt may then be endorsed stating the fact that the draughts could not be read. A practical method may be to seal the hatches with an inspector onboard – remember to a surveyor at the discharge port too to observe you unseal the hatches. Keep a written sequence of events at the load port.Cargo receiving at the ship in a damaged condition should be rejected, obviously it is not always possible to view everything but as long as you do the best you can are vigilant and exercise due diligence then there is not too much of a problem.

Bills of LadingBills of Lading are internationally respected documents on which banks will rely when advancing large sums of money.

If a master knowingly signs a bill of lading knowing that the cargo is damaged or the description is wrong then his conduct will probably render worthless any guarantee letters for any loss that has been suffered.

The Master should always be aware of the condition of the cargo, if it is impossible for him to inspect the cargo then the Bill of Lading shall be qualified accordingly.

Additionally the master will often be under a duty to state the quantity and weight of cargo shipped – once he has signed the Bill of Lading to state that, it will be very difficult to change the quantity

The intrinsic value represented by the bill of lading tends to give rise to many disputes, and therefore if there is any doubt advice from P&I clubs and owners should be sought.

Tallying Where Tallymen are employed jointly by the shipper the tally clerks receipt may take the place of the Mates receipt – in these cases Spot checks are advisable by the ships staff.

Delivering Cargo If there are any reasonable grounds for anticipating damage to cargo before opening hatches, protest should be noted.This protest should be noted as soon as possible after arrival and not later than 24hrs. It is always beneficial to the ship to have a surveyor standing by during discharge.

1. When damaged cargo is sighted in a stow a sound practice is to make a sketch or take a photo of the position of the cargo in relation to other cargos in the stow

2. All packages found broken during discharge should be laid aside and segregated

3. Care should be taken to replace back into position any cases bearings marks and numbers that may have become displaced

4. It is worth gathering up and including with other discharged cargo all torn slack or empty bags or packages especially where Bills of Lading state as certain number of bags – it is better to deliver that number of bags even if some are empty.

5. Cargo should never be delivered except on production of a Bill of Lading properly stamped and endorsed. When a cargo is consigned to order the Bill of Lading shall bear the shippers endorsement and also that of the merchant to whom it has been transferred.

6. Never deliver cargo against invoices, letters of guarantee or indemnity, if in doubt seek advice from the Owners and P&I clubs.

Stowage Plans Plans which show the disposition of the cargo loaded should

always be prepared. Inaccurate plans may cause delay and costly unproductive

employment of stevedores. During the passage – stowage plans should be carefully checked

so that any inaccuracies can be sent a head The plan should be large and should be able to show the

comparative volume of the stow. This may be the only means of conveying to agents and other discharging ports the proportion and quantity of cargo in any hold destined for that port.

Suitable info such as whether the cargo is on pallets, is stowed by a forklift truck or whether or not it is pre slung should be mentioned.

For substantial consignments the marks quantities and position of the cargo should be shown. If possible identification of individual Bills of Lading in the stow can be useful.

A copy of the plan should be sent ahead to the discharge port Bulk carrier plans must contain the total tonnage loaded into

each hatch Container plans are drawn up and delivered by the shore

organization, the weight of each container must be recorded and where appropriate if the cargo is hazardous the IMDG code should be displayed.

Task – Revision Notes: Cargo Handling Equipment

The Bale Sling Strop (Sling) This is more commonly referred to as a sling or a rope strop. It is a never-ending piece of rope, where the ends have been spliced together.

Used to sling cases or bales

Rope or Wire Snotters Rope or wire snotters are used when general cargo is being discharged. Care should be taken so that the wire is not allowed to slip along the smooth steel surface, this can be reduced by the insertion of dunnage between the wire snotter and the cargo.The snotters should be spread evenly to share the load of the lift.   

Used to discharge general cargoes

Cargo NetsCargo nets come in two types rope and wire rope. The wire rope cargo nets are designed for carrying heavier loads with greater safety, and the net does not tend to distort even under the most testing conditions.

Used for lifting stores, baggage etc…

PalletsPalletised slings of cargo can be prepared before the arrival of the vessel, to reduce cargo handling time. The cargo is stacked on wooden pallets, which allows easy handling and fork lift handling. The cargo stow may be covered with shrink-wrapped polythene or banding straps to protect and secure.

Timber Dogs These are used for the lifting of heavy logs. The weight of the log causes the sharpened dog to embed into the end of the log. Caution should be observed with this method to ensure that the dog is embedded before commencing the lift.   

Used for lifting logs

Drum or Can HooksWhen the chain is drawn the dogs are tensioned together by a single chain for lifting steel drums. 

Used for lifting drums

Braided Slings These are used for heavy loads such as metal casings.Extreme caution should be observed with any lift, but more particularly so with a heavy lift. Timber bearers to provide a gap for the sling to be removed safely should be employed when carrying loads of this nature.   Task – Revision Notes: Coal CargoRef: MGN 60

Properties of coal Coal gives out Methane, Methane & air (5%+16%) = an

explosive atmosphere

Plate Clamps For lifting steel plates, if this method can be utilised then it should be employed. Care should be taken that the load does not exceed the capacity of the clamp. When two clamps are employed the clamps should be mounted in the direction of pull. Only one plate should be lifted at a time.

Used for lifting Steel plates

Methane is lighter than air so it will accumulate in the top of the hol

Coal cargoes may oxidize resulting in high CO2 levels in the hold Coal may self heat and therefore may be liable to spontaneously

combust, a sure sign of this self heating is increasing levels of carbon monoxide within the hold

Coal may react with water and produce acid which may then produce hydrogen. Hydrogen is also lighter than air and is very explosive

Segregation Boundaries should be fire resistant and resistant to liquids Coal should be separated from goods class 1, 2, 3, 4, 5 in

packaged form and separated from bulk cargoes class 4, 5.1 Stowage of class 5.1 above or below a coal cargo is prohibited Coal should be separated longitudinally by a complete

compartment or hold for class 1 goods other than division 1.4

Requirements Prior to loading the shipper / agent should provide the master

with the characteristics of the cargo this will outline:o Safe handling procedure for loadingo Safe handling procedure for transporto Specifications for moisture contento Sulphur contento Size

Before and during loading the master shall ensure:o Cargo space / bilge wells are clean and dryo All electrical cables are checked and are free from defectso Ships personnel are able to measure the methane content,

oxygen content, carbon monoxide content without entering the hold

o Ships personnel are able to measure PH samples without entering the hold

Ships staff must be familiar and fully trained on the use of this monitoring equipment

If possible there are ways of measuring the temperature of the coal

The ship should carry the required BA sets Smoking and the use of any other naked flames should be

prohibited, hot work must only be if the space has been properly ventilated

Prior to departure the master must be satisfied that the surface of the coal has been trimmed level so that there are no spaces

in the edges of the hold – gas pockets could form if there are spaces

The atmosphere above the space should be regularly monitored, the frequency of this monitoring depends on the information given by the shipper

Ventilation of the holds Unless directed otherwise all the holds should be ventilated for

the first 24 hours after departure If after 24hours the Methane concentrations are acceptably low

the ventilators should be turned off The master should as far as possible ensure that any gases

emitted do not accumulate in any adjacent spaceso All spaces / passage ways should be regularly monitored

for the presence of methane, O2 and CO2, adequate ventilation should be installed within these spaces

Regular bilge testing should be carried out, bilges should be kept dry if there is any sort of PH risk evident

Any behavioral changes in the cargo with in the voyage should be noted and should be supplied to the shipper

Methane emitting coals Surface ventilation should be maintained but the air must not be

directed into the cargo itself Ensure that the hold is ventilated fully prior to opening the hatch When opening hatches it must be done carefully to avoid sparks Personnel must not enter the space unless:

o It has been ventilated and declared safeo Is gas freeo If it is an emergency then the Hold may be entered by

trained personnel wearing BA

Self heating coals If analysis of the hold shows increasing carbon monoxide levels

the following shall be done:o Close hatches immediately after completion of loading that

holdo Surface ventilation should be limited to the absolute

minimum time necessaryo Forced ventilation shall not be usedo Personnel should not be allowed to enter the hold unless

wearing BA and if vitally necessaryo If at the time of loading when the hatches are open the

temperature exceed 55ºC expert advice should be obtained

If Carbon monoxide levels still continue to increase self heating may be occurring

o The space should be closed down o All ventilation should be shut offo Expert advice gainedo Water should NOT be used for fighting coal fires but may

be used for boundary cooling Information to be passed on to the owners:

o Identity of holdso CO, methane O2 concentrationso Coal temperatureo Times of gas sampleso Times ventilators were opened and closedo Quantity of coal in the hold involvedo Type of coal as per the shippers declarationo Date loaded and ETA at the discharge porto Comments and observations

Task – Revision Notes: General cargoes

Carrying Dangerous goods

Hazards to ship and personnel Risk of explosion when carrying flammable or explosive

substances Oxidizing Substances and Organic Peroxides burn easily giving

off oxygen which helps fuel the fire Corrosive materials may cause damage to the ships steel work or

create an acid if water is allowed to mix with it

Minimization of the hazards Reject leaking or damaged packaging Poisonous substances to be handled with care, PPA should be

worn and BA should be standing by Any strong smells indicating leakage should be investigated Smoking to prohibited and flame arrestors to be fitted

Statutory Publications Ships intending to carry Dangerous goods are required to have a

Document of Compliance Statutory Instrument 19 IMO Code of Safe Practice for the Stowage and Securing of Cargo Emergency procedures for ships carrying Dangerous goods EMFAG Code of Safe Working Practices

Hold Preparations To be cleaned, washed and kept free of moisture To be ventilated regularly All holds are to be watertight Fire fighting systems to be operational Lighting equipment is to be in good order

Cargo Handling Persons handling the goods should be fully aware of the nature

and any hazards possible with the cargo Loading and Discharge shall be done with the utmost care If possible Dangerous Goods should be handled during daylight

hours Before loading all Dangerous Goods packages are to be

thoroughly checked Water reacting cargoes must not be stowed on deck

Cargo Securing All dangerous goods are to be tightly stowed and well secured

against any movement – attention should be paid to ensure there is no chafe

Dangerous goods in containers are secured as with any normal container

Cargo Care Temperature and humidity should be monitored Goods requiring proper ventilation should be ventilated Soundings must be taken to ensure that there is no water in the

holds Check lashing regularly Weather tightness of hatches to be checked

Refrigerated Cargoes

Hazards to ship and personnel Deficiency of oxygen occurs when ozone is used to eliminate

odors Chemicals used inside the refrigerant are harmful to people Very cold holds are a risk to personnel

Precautions to minimize the hazard Use environmentally friendly chemicals Proper entry checks made before entering into holds – ventilate

first Thermal clothing to be worn

Statutory Publications Code of safe practices for cargo stowage and securing SI 19

Hold preparations Compartments to be taint / odor free Insulation to be inspected Ventilators leading to other compartments to be un plugged Bilges cleaned and suctions tested Dunnage to be pre cooled before use

Cargo Handling Cargo nets to be used for slinging meat or fruit Walking on cargo is not allowed unless you use a walking board Temperature in hold should be as per cargoes requirements

Constantly check C02 levels when loading C02 emitting cargoes

Cargo Stowage Boxes should be the self ventilated type Distribute cargo uniformly over the floor Temperature in hold should be as per cargoes requirements

Cargo Securing Stow uniformly Reefer containers to be lashed the same way as normal

containers

Cargo Care The temperature, humidity, C02 and OZONE levels to monitored

regularly Eggs and butter are very liable to taint so do not stow with fruit Defrosting should be carried out as per the shippers instructions Good ventilation should be given to fruit to avoid C02 build up

Task – Revision Notes: Timber Cargoes

Due to the high stowage factor a vessel will not be down to her marks when her holds are loaded full of timber.Two methods to bring the vessel to her marks:

1. Load ore into the bottom of the holds – proper separation is required to stop the timber absorbing moisture from the ore

2. Stow more timber on the deck – if this is done you must follow additional regulations:

Timber must be compactly stowed and secured by a system of overall lashings of adequate strength with efficient and easily accessible methods for quick release

If uprights are necessary then the distance between them must be not more than 3m

The maximum height of timber above the deck if the vessel is in the winter zone during the winter period remains 1/3 of the extreme breadth of the vessel

When a vessel is loading as required by the timber load line rules the following must be adhered to:

Timber to be stowed solidly in wells at least to the height of the focsal

If there is no superstructure at the after end of the vessel the timber must be extended to at least the after side of the after most hatchway

The securing lashings shall consist of not less than 19mm close link chain

o These lashings shall not be independent of each othero Not more than 3m aparto Fitted with slip hook and stretching screwso Wire rope lashings shall have a short length of long chain

to permit the length of lashing The lashings are secured to eye plates attached to the

sheerstrake or deck stringer at intervals of not more than 3m. The end one is to be not more than 2m from the superstructure bulkhead

If there is no bulkhead then eye plate lashings are to be provided 0.6 – 1.5m from the ends of the timber deck cargo

If the timber is in lengths of less than 3.6m the spacing of the lashings shall be reduce.

StabilityThe stability book onboard should have comprehensive calculations in it regarding to:

The increased weight of the timber deck cargo due to o The absorption of water in dried timbero Ice accretiono Variations in consumableso The free surface effect of liquid in tankso The weight of water trapped in broken spaces within the

timber deck cargo and especially logs. The master should:

Cease all loading operations if a list develops Before proceeding to sea ensure that:

o The ship is upright o The ship has an adequate GMo The ship meets the required stability criteria

Ships carrying timber deck cargoes should operate as far as possible with a safe margin of stability and with a metacentric height which is consistent with safety requirements but such a metacentric height should not be allowed to fall below the recommended minimum.

Excessive stability should be avoided as it will result in violent rolling motions in heavy seas which will create large sliding and racking forces causing a high amount of stress on the lashings. Preferably GM should not exceed 3% of the breadth of the vessel.

Testing, examination and certification of the lashing equipment

All lashing gear used for securing the timber deck cargo should be tested and marked according to the national regulations. Copies of certificates should be kept onboard.

No treatments to the gear which could hide defects shall be applied after the testing

A visual inspection of the gear shall be made at intervals not exceeding 12months

A visual examination of all securing points on the ship including uprights should be performed before loading the timber deck cargo

Tightening lashingsLashings should be tightened at the start of the voyage and then at regular intervals throughout the voyage.

Any adjustments to the lashings shall be recorded in the ships log book.

A ListIf a list occurs during the voyage it can normally be put down to three factors:

1. Cargo shift 2. Water ingress3. Angle of loll

1. Cargo may have shifted below decks or may be apparent on deck. An immediate examination should be made to determine whether the cargo has shifted. Ballasting of fuel transfer may have caused the listAny cargo shift will in most cases occur during bad weather, so it will be difficult and dangerous to send crew out to jettison cargo, this may be a last resort as it is unlikely to improve the situation, as the cargo will not jettison all at once and there is a high chance of damage to the propeller.

2. Water ingress can be determined by sounding through the ship. Pumps can be used to pump out any obvious water.

3. If the rolling of a ship prior to detection of the list has become very slow and the ship returns to the upright position in a sluggish manner then this will indicate that the ship has a small if non existent Metacentric Height. The list is therefore due to the ship lolling from one side to the other and having no righting arm to return it to the uprightThis can be rectified by adding weight down below – ballast or removing weight high up – jettisoning deck cargo. With ballasting you should fill the lowest tank first so as to regain stability quickly. If you were to fill the high side first then the ship could roll to that side and then capsize.

Any cargo jettisoned a warning to other ships should be made by all available means to let them know.

Means of lashing Hog Lashings

Publication to refer to:

Wire rope lashings

Snatch Block

Wiggle wire

Double lashing

To securing eyes on deck

To tensioning drums

Turnbuckle or lever tensioner

Code of Safe Practice for ships Carrying Timber Deck Cargoes 1991

Task – Revision Notes: Bulk Carriers

Due to the high risk nature of carrying cargoes in bulk the BC Code was introduced – ‘IMO Code of Safe Practice for Solid Bulk Cargoes’The aim of the BC code is to promote safety of stowage and shipment of bulk cargoes by:

Highlighting the dangers associated with the shipment of certain types of bulk cargoes

Gives guidance on the procedures to be adopted when the shipment of bulk cargoes is contemplated

Listing typical materials currently shipped in bulk together with advice on their properties and handling

Describing test procedures to be employed to determine various characteristics of the bulk cargo materials

The BLU Code – ‘IMO code of Practice for the safe Loading and Unloading of Bulk carriers’The aim of the BLU Code is to outline the procedures that must be followed by the ship and bulk terminal prior to and during bulk handling operation. The main idea of it is to create a standard method of operation.

BC Code Section 1: definitions

Angle of repose – the maximum slope angle of a free flowing granular material

Cargoes that may liquefy – materials which are subject to moisture migration and subsequent liquefaction

Flow moisture point – the percentage moisture content at which a flow state develops under the prescribed method of test

Stowage factor – the figure expressed that states the number of cubic meters which one tonne of material will occupy

Section 2: general precautions The main emphasis of this section is on stress and stability basically saying that special attention shall be paid to ensure that the distribution of weight is such that it avoids excessive stresses.

Section 3: SafetyThis section is concerned with the safety of the ship and personnel, and refers to MFAG of the IMDG code.

Section 4: Acceptability of consignments for shipping The main emphasis is on the testing and sampling of the proposed cargo. And that the shipper provides all relevant details concerning the cargo, including all characteristics and properties of the material. Section 5: Trimming Procedures The general requirement that the cargo should be trimmed to a reasonable level. For cargoes with an angle of repose of less than 30º the Grain Reg’s apply

Section 6: Methods of working out Angle of ReposeThis gives guidance to ships officers to work out the Angle of Repose if the figure can not be taken from ashore

Section 7: Cargoes which may liquefy Cargoes received with a moisture content above the transportable moisture limit should not be accepted and special care should given to ensure that water is not allowed to enter the hold during the passage.

Section 8: Test procedures for cargoes which may liquefy Guidance for ships officers on simple tests that can be performed on cargoes which may liquefy

Section 9: Materials with chemical hazardsMost of these are covered in the IMDG code but many only become hazardous when carried in bulk. The section also covers the requirements for segregation between bulk materials processing chemical hazards and dangerous goods in packaged form and incompatible bulk materials processing chemical hazards.

BLU Code Section 1: The terms associated with bulk cargo

Section 2: The suitability of ships and terminalsThis discusses the obligations of the ship owner and manager when offering a ship to carry a particular bulk cargo. Also the obligations of the terminal in bringing the vessel alongside the berth

Section 3: Procedures between the ship and shore before arrival Provides considerable detail of the load sequence, stowage by hold order of loading and quantity to be loaded. Once the terminal has received that information the terminal will provide the ship with the information regarding the berth and the cargo operations.

Section 4: Procedure between ship and the shore after arrival but before handling This basically regards the Master / Mate relationship with the terminal

Section 5: Loading and handling of ballastBrief details on what is expected from ships officers and the terminal operations staff during the actual loading operation. On completion the code requires the master and the terminal agree that the ship has been loaded according to the plan.

Section 6: Unloading and handling of ballastThe same as section 5 but this time with regards to unloading the cargo

Planning the Load Determine the amount of ballast to be on board at berthing or un

berthing Determine the other weight onboard such as fuel and fresh

water. Calculate the total amount of cargo to be loaded Calculate the individual tonnages if more than one grade or if

more than one loading / discharge port is involved Plan the amount of cargo in each individual loading pour or

discharging sequence Match the deballasting / ballasting sequence with the cargo

operation to keep hull stresses within the required limits Write down the expected time intervals for each pour and ballast

operation to ensure the synchronisation Plan for draft checks at critical points throughout the load or

discharge Ensure ballasting will be completed prior to the final trimming

pour and final draft survey Plan the final trimming pour

Loading the cargo Arrive within the port limits in ballast with any floodable hold

empty and all holds ready to receive cargo Issue of the Notice of Readiness by the master Holds inspected and Notice of Readiness accepted Arrive at the loading berth, Chief Officer and Terminal agree on

the checklist and load sequence, the initial draft survey is conducted before the hatches are opened and prior to starting deballasting

Loading and deballasting begins ensuring that the pumping and the loading match the plan

Draught checks are carried out at various stages throughout the loading for comparison with the terminals figures

Each hold is loaded with the correct number of pours in the correct load sequence

Ballast completed prior to the final draught check and before the trimming pours

Trimming pour completed to give desired trim and deadweight Draught survey to ensure correct load tonnage and distribution

of trimming pours Final inspection to ensure correct cargo levels and hatches are

secure for sea Bill of Lading signed, time sheets and statement of facts agreed Terminal received confirmation that the loading was completed

as planned Port clearance give ship sets to sea

Ventilation of the holds Ventilators should be directed as follows:

Leeward vents facing into the wind Windward vents facing away from the wind

Hot to cold – ventilate holdCold to hot – ventilate not

Task – Revision Notes: Container Ships

The standardisation of containers has been brought about by the:‘IMO International Convention for safe containers.’The main goals being to maintain a high level of safety of human life in handling and transport of containers – done by providing strength requirements. And to facilitate the international transport of containers by providing uniform international safety regulations.

The outcome of the convention is that containers that have been safety approved for international transport will have a safety approval plate on them.

CSC Safety Approval

[GB-L/749/2/7//75]Date Manufactured ………………Identification No. ………………Maximum Gross Weight …Kg …lbAllowable stacking weight for 1.8g

…Kg …lbRacking test load value …Kg …lb

[GB-L/749/2/7//75] this code specifies the Country that approve the container, the rest of the numbers are the approval reference

Month and year of manufacture The Identification number is provided by the manufacturer Maximum operating weight The allowable stacking height – the weight that the container can

support from above it The load applied for transverse racking tests

Other types of container General purpose container – the standard container in use Bulk container – 20’ container with three hatches in the roof for

loading bulk material Ventilated container – 20’ with a passive ventilation system

adjacent to the top and bottom side rails Open sided container – 20’ with an open side to it with a gate

and a roll down curtain, may be used to carry livestock Open top container – 20’ or 40’ used to carry large heavy, tall

goods that can be loaded through the roof rather than the door. Roof battens can be fitted after the cargo is secured

Half height containers – 20’ or 40’ used to load high density cargoes when a full container would not be filled

Flat rack containers – 20’ or 40’ with no sides or roof Insulated containers – used when there is blown air available

from the ship Refrigerated containers – similar to the insulated container but

they have a refrigeration supply fitted to them which can be plugged into the ships power

Tank containers – 20’ or 40’ framework steel tanks used for carrying hazardous and non hazardous liquid

Cargo Planning The cargo space on a container ship is well know due to it being

made up of equal slots so the basic plan is always the same. Each container space has a 6 figure code which specifies the

position of it. And tells you the fore and aft position, the athwartships position and the vertical position.

o The first two figures specify the row number which starts from the bow. Odd numbers = 20’ and Even numbers 40’

Therefore a 20ft container in the furthest bay fwd would start with 01, if it was in the next available bay then it would start 03

If a 40ft container was in rows 1 and 2 then it have the prefix 02

o The second pair of numbers tells you its athwartships location starting from the centreline. Odd numbers = stbd and Even numbers = port

Therefore 06 = the third cell from midships on the port side

o The third pair of figures tells us the vertical location, Full height containers are Even numbers starting with 02 and half height containers are Odd numbers. On deck the lowest tier is 82

For each bay a complex plan is drawn up which includes Ports of loading and discharge Contents Weight Container Number

This leads the planner to various other issues as he needs to know any special requirements such as DG or Refrigeration

The weight of eachcontainer must be know to distribute the weight evenly

Distribution of cargo must be planned carefully to avoid double handling of cargo which discharging

Provision for oversized units

These various factors would make the planning very difficult for the ship to do it as they are unlikely to have sufficient information, therefore it is done by specialist planners

Loading the containersContainer ships are made up of cell guides below decks and sometimes above decks this means that it is almost impossible to load the containers if the ship is not upright. The ships therefore are fitted with automatic ballast systems which trigger water to be pumped between wing tanks.

Securing ContainersThe ‘IMO Code of Safe Practice for Cargo Stowage and Securing’ only requires that ships that carry cargo in standardized stowage and securing systems should:

Designed and equipped that the standardized cargo concerned can be safely stowed and secured onboard under all conditions except during the voyage

Provided with adequate information for the use by the master on the arrangements provided for the stowage and securing of the specific cargoes for which the ship is designed

Therefore it is necessary that the ship has an approved securing manual and the necessary equipment onboard

Lashings must be checked before sailing to ensure that they are tight and then again during the voyage.

If a master suspects that the cargo within a closed container has not been properly secured within the container then a Cargo Stowage and Securing Declaration should be sighted or refused

Task – Revision Notes: Reefer cargoes

Conventional reefer ships still carry the majority of refrigerated cargo but are also equipped to carry containers above and below decks. These ships generally have a greater number of individual spaces than that of a general cargo ship. This division of space means less containers in a stack so there is a greater variety of cargo that can be carried. Due to the high amount of palletised cargo that is carried the dimensions of the hold are generally in pallet sized multiples.

Cargo is kept at its required temperature through a combination of efficient insulation and refrigeration. The temperature control is performed by blowing refrigerated air through the space into the cargo. The main purpose of refrigeration is basically for organic reasons, as organic material is prone to attack by micro organisms, bacteria and mould. These all require warmth to be able to multiply.

Living organic matter omits heat and gasses, CO2 and ethylene which is produced by ripening fruit – ethylene will speed up the ripening process.

Loading The space must be clean, dry, free of odour and be pre cooled.

Cleaning – washing down with a disinfectant and deodoriser, perhaps painting will be required, clean fans by running them in both directions so that dust is blown from the trunking. Scuppers must be cleaned. Clean dunnage must be laid out and the hold must be fumigated.

Freeing odour – this will pretty much be done in the cleaning process

Pre cooling – this is achieved by bringing the temperature down to slightly below the carrying temperature and maintaining the temperature for a period of 24hrs

The cargo must be fully inspected and the publication ‘The transport of Perishable Foodstuffs’ or ‘Guide to Food Transport’ should be consulted. The cargo should be in its transportable state as the ship is only there to maintain the temperature not lower it.

The cargo should be loaded so that the air flow is not restricted – if the cargo has bellies they should be stowed belly to belly rather than in the gaps so air flow is not restricted.Dunnage should be used to keep the cargo away from ships sides and also to ensure that the air is allowed to freely circulate.

Compatibility of cargoGreat care should be taken in mixing cargoes.

There should be sufficient overlap of temperature limits to allow normal fluctuations in temp

Packaging and stowage patterns – mixing items may cause stowage problems and air circulation problems

Ethylene production / sensitive cargoes could lead to un acceptable ripening of cargoes.

Odour emission and sensitivity of cargo

Care during transportationThe conditions of carriage should be strictly kept to, monitored and recorded. Proper documentation of cargo space conditions will assist the ship owner if claims are made against him.Record:

Temperatures Fans should run at speeds necessary to maintain temperature

and meet ventilation requirements, excessive ventilations could cause the cargo to dry out

Ethylene levels should be controlled by venting a proportion of circulated air to the atmosphere and replacing it with fresh air

CO2 may be injected into the circulating air to maintain required levels

Discharging cargo Stevedores are generally experienced at the loading port but at the discharge port will probably require more assistance.

When working a cargo which is below another cargo, screens should be erected to stop heat getting in the hold

Spaces should be temporarily covered during short breaks and cooling fans run

When required to walk on meat they should have clean boots on Walking boards should be used when working on cartons or

cases of fruit Cargo slings should be made up at the edges of the hatch to

prevent damage When damage is found in the stow all details should be carefully

noted so that the cause can be found and perhaps avoided in the future

Task – Revision Notes: Ro – Ro

‘The merchant shipping (carriage of Cargo) Regulations’The regulations require the shipper to provide the owner or master with a description of the cargo, gross mass of the units and any special properties of the cargo, so that they are able to ensure compatibility and safe stowage of the cargo.

The regulations require the owner and master to ensure that ‘appropriate precautions are taken during the loading and transport of cargo units, especially with regard to securing arrangements on board such ships and on the cargo units and with regard to the securing points onboard.

There are additional guidelines in the ‘Roll on Roll off ships, stowage and securing of vehicles code of practice’

Section 1

Principle sources of dangerSection 2

Considers the protection of personnel on ramps and vehicle decks Section 3

Guidance on the use vehicle decks, ships ramps, lifting appliances and securing arrangements

Section 4Aimed at shippers ensuring vehicles are suitable

Section 5Stowage and securing for ships officers

Shippers advice should be followed regarding the handling + securing of vehicles

Vehicles should be aligned in the fore and aft direction Stowed as closely together as is possible in the

athwartships direction, so as to restrict movement in the event of lashing failure

Safe access to securing arrangements, stairways and escape routes

Parking breaks to be on Freight vehicles of more than 3.5T should be secured in

all circumstances Vehicles on inclined decks should be chocked Lashings should only be made on proper securing points

at equal tension Securing operations should be completed before sailing

Section 7Refers to the cargo securing manual

Details of fixed securing points, pad eyes, eye bolts and elephant feet

Locations and stowage of portable securing gear Examples of correct application of portable securing

gear on various cargo units, vehicles etc Indication of the variation of transverse, longitudinal

and vertical accelerations to be expected in various positions onboard

Design and operation Closing and locking of doors prior to departure (enter in logbook) Indicators and alarms showing the status of door CCTV in cargo and door areas on the bridge Passenger counting system Provision of draught, trim and stability information before departure Lightweight survey every 5 year (inclined of 2% difference) Must have a Co-operation with SAR services plan

Compliance with “stowage and securing of vehicles code of practice”

BallastDue to the Ro-Ro vessels being able to load horizontally it is important that the ship is kept so. Modern tractor units are capable of towing up an incline of about 10º so it is important to keep it to about 6º so therefore it is important that proper use is made of the ballast to keep the ship at an acceptable level.

A/Amax

The value given to a ship to indicate its survivability in the flooded condition

Task – Revision Notes: Passenger Ship Operations

Passenger ship Safety CertificateThe PSSC is a SOLAS requirement and must be carried on all UK flagged Pax ships engaged on international voyages. It covers Construction, Equipment and RadiosSurveys are carried out each year.

Items inspected on the initial survey Construction, machinery and equipment Safety equipment Radio equipment

Sub division load lines – these may be assigned for the use on alternative service conditions. The line would depend on the passenger spaces in use.

Some of the things that can be found on the certificate: Operational sea areas Main and auxiliary machinery and boilers Watertight subdivision arrangements Fire system and appliances Radio installation Navigation equipment and publications Lights shapes and sound signals and distress signals Means of embarkation for pilots

A record of equipment detailing the LSA and FFA onboard as well as details of the radio facilities must supplement the certificate.

Muster lists and Drills

Muster Lists The Master is responsible for compiling the muster list and ensuring it is updated and placed in places throughout the ship including the bridge, engine room and crew accommodation. It shall have on it:

A translation into the working language of the ship Contain details of alarm signals, communications and abandon

ship signal Show duties of each crew member The survival craft assigned to each person Ensure that a deck officer or qualified person is command of

each survival craft Indicate a person capable of carrying out survival craft engine

repairs The location of passenger assembly points The person responsible for the up keep of LSA and FFA

DrillsEach crew member must participate in at least one abandon ship drill and one fire drill every month.These drills must be held within 24hrs of leaving port if more than 25% of the crew have not taken part in drills on board the ship.Additionally on Pax ships these drills must be conducted weekly and as many crew as practicable should take part, such that every crew member participates once a month.

A muster of Pax must take place within 24hrs of their embarkation and they must be give instructions on the following:

Actions to take when hearing the GES Location of and how to put on a life jacket GES and the signal to abandon ship Importance of being properly clad Dangers of jumping into the water Watertight doors and fire doors

If a small number of Pax join after the drill there attention should be drawn to the safety instructions in their cabinsThese instructions should include:

Muster station Action to take on hearing GES Location and method of putting on a lifejacket

Requirements for crew dealing with passengers in emergenciesAll crew nominated to assist pax in an emergency should receive additional training to enable them to perform their duty. The crew should be proficient in:

Communications – Sufficent English to provide instructions, raise alarm, report and notify

Life Saving – Knowledge of the muster list, GES and areas of responsibility and general ship layout

LSA – Location of life jackets and blankets First Aid – basic first aid and transportation of casualties Fire – raising the alarm, initial containment, dangers of inhalation Abandon ship – Signal and use of survival equipment

Methods to improve and maintain crew proficiency Practical training onboard Familiarization – i.e. repeated tours Participation in drills Exercises in use of equipment Exercises in use of communication equipment Evacuation exercises Real life drills Attendance of Crisis management and Human Behaviour courses

Crisis Management and Human BehaviourResearch has shown that:

60% of people will not know what to do and will become confused and will require specific instructions + direction

25% of people will act rationally and will help others 15% of people will experience ‘Spontaneous Incompetence’

Basically wont be able to move or believe the seriousness of the situation

Of the 25% rational people:

o 10% will look after themselveso 10% will assist otherso 5% will try and deal with the emergency – these

people can get in the way – they may try and persuade others to do what they say rather than listening to the crew – retired police, fire fighters etc…

Information to the passengersOn sounding the GES make regular and honest announcements – this will gain confidence and trust.

Behaviour of the crewThe crew provides leadership and reassurance. Signs of fear will distress pax – best way to be is almost a dictator – ‘I am trained for this situation, here’s what we are going to do and if you follow my instructions we will all survive’

Problems likely to be encountered Elderly – may be left to fend for themselves as some pax

demonstrate selfish and aggressive tendencies towards others to save themselves

Pax will demand to return to their cabins, if they are not allowed to then they will become angry

Pax will attempt to bring luggage with them List, smoke – will confuse pax so expect them to be disoriented

Emergency information for passengers – MSN 1409

The overall aim of providing information to pax keeping them sufficiently well informed throughout an emergency.It is essential that pax are informed of the of procedures that should follow in an emergency – this information should be communicated to pax on or before departure.

There are 5 requirements to assist pax in an emergency these are:1. Continuously illuminated signs to be provided in passageways

and stairways indicating direction to muster stations2. All doors used for exits to open decks and all emergency

escapes be clearly marked to indicate their purpose3. All vessels are provided with a public address system4. Instructions on muster stations, lifejackets etc to be posted in

cabins and conspicuous places5. Where a drill is not held on departure the attention of

passengers is drawn to the ships emergency instructions

Signs Muster Station signs should be located at muster stations and

readily apparent to pax so they can readily identify the muster station

Muster station direction signs provided in alleyways, stairwells showing how to get to muster station

Exit signs – all doors leading to open decks and doors, windows etc… used for emergency escapes. Signs should be placed on door or in a position to indicate the presence of the door

Deck identification – the number / name of deck should be readily identified by signs at each entrance and stairway

Public Address systems These should be capable of broadcasting to all public spaces

which includes open decks. It should be powered from the main electrical source and from an

alternative power source.

Decision Support SystemPassenger ships Classes I, II and II(a) are required to have a decision support system for emergency management.The plan must identify all foreseeable emergency situations and for each emergency have an emergency plan / procedureAreas that shall be included in the system are:

Fire Damage to the ship Pollution Security Threats Serious accident to Pax and Crew

Whenever possible the drills and training onboard will make use of the decision support system

Bomb threatsReception and bridge have a set format of questions to ask the caller

What group is making the threat What threat is there to the ship Any time limit of the bomb Demands of the group What the group hopes to achieve Male or female Regional accent Background noise Calm or panicked Rational or irrational

Task – Revision Notes: Seaworthiness

The owner is obliged to provide a seaworthy vessel. Common law recognizes that vessels can not be absolutely water tight in all conditions and that owners can not guarantee the seaworthiness of a vessel once she leaves port and is subject to the perils of the sea.

“Perils of the sea: fortuitous accidents or casualties peculiar to transportation on navigable water; stranding, sinking, collision, heavy weather or other unusual forces of nature.”

The requirements of common law as stated in the Hague rules and the Hague Visby rules, that the vessel left her berth in a seaworthy condition as far the owners, master and officer could tell by careful reasonable inspection.

A vessel will be deemed to be un-seaworthy if she set sail without: Valid statutory certificates Valid certificate of class Proper stowage and securing of cargo Cargo care system in good order A properly qualified master and crew The proper crew complement as outlined by the safe manning

certificate Appropriate charts and publications for the voyage which are

corrected and up to date Sufficient bunkers for the voyage

Consequence of un-seaworthiness is breach of contract with the possibility to terminate contract. If the cargo owner can show that his loss was caused by a failure of the carrier to exercise due diligence to make the vessel seaworthy, then the carrier will not be able to rely on any other clauses in the Rules which reduce his liability. If the loss or damage was caused by un-seaworthiness on the part of the ship the burden of proving that due diligence was carried out is on the carrier or other person claiming exemption under Article IV. If the Hague Visby Rules apply then there are 17 exceptions to liability that the carrier can use to avoid being responsible for loss or damage. For example: act, neglect, or default of the master, mariner, pilot or the servants of the carrier in the navigation or management of the ship. So the carrier will be looking to show that the ship was seaworthy for the voyage (HVR. Article III/1) and that any loss or damage was caused by one of the exceptions to liability (HVR. Article IV/2).

Task – Revision Notes: Load Lines

When a ship loads in a summer zone she can load to the top of her summer marks this is also the statutory freeboard mark.

If the vessel is in fresh water then she can load to the top of her ‘F’ fresh mark, when she returns to the open sea (summer zone) the vessel will return to the Summer Marks

Similarly if she loads in a winter zone then she can load to the ‘W’ mark, then when she returns to the summer zone she will sink to her summer mark

The ships dock water allowance is the allowance given to a vessel so that she can load in Dock water, when she does this she will be over her Summer Marks, but due to the fact Dock water allowance has been calculated the vessel will be at her Summer Marks when she returns to open sea.

Dock water allowance = FWA x (1025 – Density of the dock water) 25

S is the position calculated from the Load line rules W is one forty eighth of the summer load draught below S T is one forty eighth of the summer load draught above S F is an equal amount to Displacement

4T above SDisplacement at the summer load draught and T is the

metric tones per cm immersion TF is the position relative to T and is found in the same way as F

relative to S WNA This is used by vessels not exceeding 100m in length when in

certain areas of the North Atlantic Ocean during the winter period. When assigned it is 50mm below the Winter marks

Diagram of a standard Load line

Timber shipsCertain vessels are assigned Timber load lines after they have met all the required criteria.

LS is arrived at from the appropriate tables in the Load line Regs LW is one thirty sixth of the summer timber load draught below

LS LT is one forty eighth of the summer timber load draught above

LS LF and LTF are calculated in the same way as F and TF except

that the displacement used in the formulae is that of a vessel at her summer timber load draught.

LWNA is at the same level as WNA

Timber load line

Task – Stability Notes: Angle of Loll

The angle to which a ship with a negative initial metacentric height will lie at rest in water

An angle of loll can occur due to a number situations: Deck cargoes absorbing moisture especially timber deck

cargoes, you should allow up to 15% extra for weight that will be absorbed during the voyage when making the initial calculations.

Consumption of fuel and water thus creating Free Surface and a rise in G

Ballast tanks may lower if water is lost through the vent pipes during rough weather. Ensure that ballast tanks are kept pressed up.

Poor cargo and ballast tank management is the usual cause of angle of Loll.

Heavy lift operations causes an instantaneous loss of GM when the weight is lifted off the deck, such a large increase in KG should be considered prior to the lift.

Shift of bulk cargo

It is not always easy to work out if the ship is listed or is lolled, and if you are in any doubt always treat it as though the vessel is lolled.

Once you are satisfied that the weights are distributed evenly then we can assume that the list is due to negative GM.The main priority is to lower the Center of gravity so it goes below M – the initial metacentric height. All slack tanks should be pressed up as this will stop a rise in G due to free surface effect. Anything on the ships decks should be lowered for example Derricks should be lowered. Oil in tanks should be transferred to bottom tanks.

If the ship has high ballast tanks then these should be emptied high side first, as the high side will lower G the most.

Once this has been done and there is a still a list there what can we do???If there are empty bottom tanks we could fill these, but in the process of doing this there will be free surface effect with will cause an increase in the negative GM thus creating a greater angle of loll. If it is possible to fill tanks then you should consider filling the smaller tanks first.

If there is a tank with a split at the centre which side do you fill first and why?If you were to fill the high side first then the ship would roll upright then would quickly roll over to the other side creating an angle of loll on that side, there is a high chance that the ship could capsize as it rolls over. So fill the lower bottom tanks, this will initially list the ship over further but it is being done in a controlled manner, as you move the center of gravity downwards the list will eventually start to decrease, when this starts to happen you can start filling the other sides bottom tanks and bring the ship up right in a controlled manner.

A ship with a negative initial metacentric height is unstable when inclined, As the heel angle increases the center of buoyancy ‘B’ will move out so it becomes directly below G this is called the angle of Loll, at this time the capsizing moment has gone.When the angle of Loll and the GZ is zero G remains on the Center line. If the ship continues to heel past the angle of loll B will move out to vertically under the low side thus allowing the ship to return to the angle of Loll. If B does not move out far enough the ship will end up capsizing.

ALWAYS only fill 1 tank at a time.

Task – Revision Notes: Bilge and ballast systems

Bilge systemIs designed to remove excess wather from the bilge and pump it to a holding tank or over the side via an OWS

Ballast system Is designed to fill or empty water ballast tanks from the sea, or allow water to be transferred via tanks for trim /stability purposes.

Cargo ShipsAll cargo ships are provided with pumping and piping arrangements so that any watertight compartment or watertight section of a compartment can be pumped out when a vessel has a list of up to 5º and is on an even keel.

In machinery spaces they may be pumped out through 2 suction pumps:

1 from the main bilge line 1 from an independent power driven pump

Also there must be an emergency bilge pump

Passenger ShipsPassenger ships must provide the capability to pump out each compartment or section following a casualty under all practical conditions whether the ship is listed or not.

There must be at least 3 bilge pumps and must where possible be in separate compartments. The pumps and lines must be kept within 20% of the ships beam and pipes must be fitted with non return valves. These requirements are designed to try and prevent any compartment from becoming flooded during a grounding.

Bilge linesBilge lines are fitted with strum boxes at mouth of the line. The strum box is a box which covers the end of the pipe and has small holes in it

up to 10mm in diameter. The point of the strum box is to stop any dirt or debris being sucked into the lines.In machinery spaces and the shaft tunnel, the bilge line is led to a mud box, there is a fine mesh in the mud box which collects sludge and foreign objects.

ScuppersScuppers are fitted at the ships side to drain the decks.Below the freeboard deck scuppers are led to bilges rather than over the side unless they are fitted with non return valves.

Task – Revision Notes: Bilged Side compartment

A box shaped vessel of length 120m, beam 18m floats at draft 6m in salt water.

The vessel has a mid ship side compartment of length 20m calculate the angle of list if the compartment becomes bilged

Find bodily sinkage

Increase in draft = Lost volume Intact water plane area

= 9 x 20 x 6 (120 x 18) – (9 x 20)

= 0.55m

20m

18m

120m

Find new KBKB = New T ÷ 2

= 6 + 0.55 ÷ 2 = 3.28m

Find the shift in B

Area Dist of centroid

Moments

Whole 18 x 120 0 0Damaged - (9 x 20) 4.5 -810

1980 -810

Shift in B = -810 1980 = -0.41

Find BM BM = I

but I = Igg because this is for a box shape

Igg = Ixx – (A x h2)

Ixx = L x B 3 - l xb 3 12 3

= 120 x 18 3 - 20 x 9 3 12 3

= 53460m4

Igg = Ixx – (a x h2)= 53460 – (1980 x 0.412)

18m

120

4.5

Shift in B

= 53127.16

BM = Igg ÷ = 53127.16 ÷ (120 x 18 x 6)= 4.10m

GM = (KB + BM) – KG= (3.28 + 4.10) – 5= 2.38

List = Tanº = Shift in B GM

= Tanº = 0.41 2.38

= 9.77º angle of list

Task – Revision Notes: Bilging a side compartment with permeability

Find the angle of list when a side compartment is bilged and the compartment has a permeability of 0.7.KG = 5.8

Find GM in the damaged conditionGM = (KB + BM) – KG

Find KB//Sinkage = lost vol (includes Permeability)

intact WPA= 6 x 11 x 17 x 0.7

(130 x 11) – (11 x 17 x0.7)= 0.6m

130

11

6

17

New Draft = 6.0 + 0.6= 6.6m

KB = 6.6 ÷ 2 = 3.3m

Find BM = LB3 – lb3 x permeability 12 12 = 130 x 113 - 17 x 113 x 0.7 12 12

(130 x 11 x 6) BM = 1.53m

Now you can find GMGM = (3.3 x 1.53) – 5.8

= - 0.97

Find HeelTanº = 2 x – GM

BM

= 2 x –0.97 1.53

= 48.39º

Negative GM therefore there is an angle of

Task – Revision Notes: Bilging an end compartment

Find the fwd and aft draughts when an end compartment is bilged

KG = 5.0m

//sinkage = lost vol intact WPA= 8 x 13 x 14

(14 x 115) – (13 x 14)= 1.02m

Draft at LCF = 8 + 1.02 = 9.02m

LCF B51

115 13

14

8

Centroid

57.5

57.5 G

Change in trim = Trimming Mom MCTC

= LCB LCG = 57.5 – 51 = 6.5m Δ = x P = (8 x 115 x 14) x 1.025

= 13202T

TM = 6.5 x 13202= 85813Tm

Buoyancy force = Lost vol x P= 8 x 13 x 14 x 1.025= 1492.4T

Distance from the LCF to the Centroid of the damaged compartment is 57.5m

MCTC = Δ x GMl 100 x LBP

GML = KB + BMl – KG

KB = New draft ÷ 2 = 9.02 ÷ 2 = 4.5m

BMl = Inertia Longitudinally = BMl 3 12

= 14 x1023 ÷ 12 ÷ (8 x 115 x 14)= 96.12m

GMl = 4.5 + 96.12 – 5= 95.63

MCTC = 13202 x 95.63 ÷ (100 x 115)= 109.78

Change Trim = 85813 ÷ 109.79= 781.68cm= 7.82m

Draft aft = T x W ± Trim x LCF ÷ LBP= 9.02 – 7.82 x 51 ÷ 115= 5.55m

Draft fwd = Taft ± trim= 5.55 + 7.87

= 13.37m

Task – Stability Notes: Freeboards

A change in freeboard could occur if:

Loading and discharging a cargo causing a change in draught Loading and discharging of ballast, fuel or lube oil Ice accretion Absorption of moisture by deck cargo Ingress of water in a damage situation Shipping heavy seas

The increase in freeboard will result in the following:

The initial GM will be unchanged GZ values will be increased at angles of heel beyond the angle

of heel at which deck edge immersion takes place for small free-boarded ships

Dynamical stability is increased at angles of heel beyond the angle of heel at which deck edge immersion takes place

The range of stability is increased; if freeboard were to be reduced then GZ values would similarly reduce

Assignment of FreeboardsType A ships – freeboard is extracted from Freeboard Table AType B ships – freeboard is extracted from Freeboard Table B

The freeboard is increased by a tabulated amount relating to length if the ship is fitted with portable hatch beams, covers and tarpaulins.

The freeboard can be reduced by 60% of the difference of Type A & B if:

More than 100m in length Fitted with steel gasketed hatch covers Will remain afloat when loaded to the summer load line if one

compartment is bilged The ship will then be referred to as a Type B60 ship

The freeboard can be reduced by 100% of the difference between Type A & B if the vessel complies with the requirements for a Type A ship:

Machinery casing protected Freeing arrangements and gangway access Will remain afloat when loaded to the summer marks with 2

compartments bilged The ship is then referred to as a Type B100 ship

The freeboard is increased if the length is less than 100m

Correction for depth, if the depth for freeboard exceed L/15

Correction for position of the deck line is made if the deckline is not placed at the depth corresponding to the depth for freeboard

Standard height and length of superstructures are tabulated against ships length

A standard sheer profile is defined by ordinates measured as a function of the ships length

Minimum bow height – this is the distance at the forward perpendicular between the summer load line and the top of the exposed deck at side. Freeboard will be increased if the bow height is less than the minimum bow height until they are equal

The result of these calculations will allow the freeboard to be assigned.

Timber freeboardsThe summer freeboard is calculated as for a type B ship with weather tight pontoon or steel hatch covers without the -60% or the -100% allowance

Task – Revision Notes: Freeboard Assignment

Type A vessel Designed to carry liquid cargo in bulk Has small watertight steel gasketed hatches High watertight integrity of decks Low permeability of cargo

Type B vessel All other types of ship

Assignment of freeboard Tabular freeboard in found in tables A and B of the Loadline regs This is multiplied by a correction for block coefficient which gives

you the basic freeboardNext:

1. Sheer – if there is an excess beyond the basic template then there is a reduction in freeboard

2. Superstructure – the structure provides additional buoyancy and therefore the freeboard can be reduced

3. Trunks and forepeaks – these again provide extra buoyancy so the freeboard can be reduced

4. Minimum bow height – the vessels freeboard is increased until the minimum bow height is reached

5. Correction for effective deck edge 6. Depth correction – freeboard is increased if Length ÷

Breadth is greater than 15 Once all the corrections have been made the freeboard can be assigned

The freeboard is increased by a tabulated amount related to length if the ship is fitted with portable hatch beams covers and tarpaulins.

Type B60 shipsThe freeboard can be reduced by 60% of the difference between the freeboards extracted from the Tables A and B if the ship is

More than 100m in length Fitted with steel gasketed clamped hatch covers in Positions 1

and 2 Will remain afloat when the loaded to the summer load line with

one compartment flooded other than a machinery space. If the vessel is more than 225m then the machinery space is

considered a floodable compartment

Type B100 ships The freeboard is reduced by 100% of the difference between the freeboards extracted from the Tables A and B if the ship additionally complies with the requirements for a Type A ship

Machinery casing protection Freeing arrangements Gangway and safe access The ship must remain afloat when loaded to the summer draught

and two adjacent compartments are flooded other than the machinery compartment

In vessels over 225m in length then the machinery space is considered a double compartment

Task – Revision Notes: Change in Draught

A vessel displacing 8000T in SW has a TPC of 10.5cm The vessel moves into FW then loads 340T Calculate the change in draught.

FWA = W 4 TPC

FWA = 8000 4 x 10.5

= 190.47cm

Load cargo in FW= 340 x 1025 10.5 1000= 33.2cm

Total change in draft = 190.47 + 33.2= 52.24cm

Example 2The statutory Summer Freeboard of a vessel is 4300mm. At a certain time in RD 1006kg/m3 in a summer zone the freeboard on the port side is 4290mm and on the stbd side is 4280mm.The FWA is 175mm and TPC salt water at and near the load draught is 25.2. How much more cargo can be loaded?

Freeboard Port = 4290mmFreeboard Stbd = 4280mm

Mean = 4285mmStatutory Freeboard = 4300mm

= 15mm (Therefore S line is 15mm below the surface)

DWA = FWA (1025 –d)25

= 175 x (1025 -1000)25

= 133mm

Change of draught = 133 – 15 = 118mm= W ÷ TPC

W = Change of draught x TPC= 11.8 x 25.2 x 1006

1025= 291.85T

Example 3Calculate the amount of cargo to load so that the ship will sail at her maximum draughtsPresent draught Fwd = 9.37m

Aft = 9.89mIn water RD 1.010. Cargo to discharge = 540T and load 970T of bunker.FWA 210mm Summer draught in SW = 9.98mMean TPC 63

Present Draught = 9.37= 9.80

mean = 9.63

DWA = 210 x 15

25 = 126mm = 0.12m

Summer Draught SW = 9.986mSummer Draught DW = 10.106mPermitted sinkage = Summer draught – Mean present draught

= 10.106 – 9.63= 0.476m

Increase in Δ = 47.6 x 63 x 10101025

= 2955T

Loaded and DischargedBunkers + = 970TCargo - = 540TNet = 430T

Cargo to load = Δ – Net loading= 2955 – 430 = 2525T

Task – Construction Notes: Forces

Vertical Shear ForceVertical shear forces are the forces which occur in sections where there is non uniform excess buoyancy or excess load.Due to the vessel being intact these vertical upwards and downwards forces will slightly distort the vessel.

Longitudinal shear forces compliment the vertical ones.

If the ship has excess weight at either end the vessel tend to ‘Hog’ and if there is excess weight amidships the ship will ‘Sag’. Similarly if a ships on a wave and she is supported amidships she will Hog.

Torsion When a body is subject to a twisting moment which is normally referred to as torque.

For Example a ship heading across waves at a 45º angle will be subject to righting moments different at either end creating a twisting effect. Most ships have very small torsion moments, but container ships special torsion box girders are fitted to the high sides of the ship. These girders are specifically designed to reduce this twisting effect.

Static loadingA transverse section of a ship is subjected to static pressure from the surrounding water in addition to the weight of cargo.Although this transverse stress is not a major issue, but if inadequate stiffening was not present then major structural distortion would occur.To resist the transverse stresses, transverse bulkheads, floors in double bottoms, deck beams and side frames are fitted

Vibration StressesVibration from machinery onboard is constantly there, it can result in fatigue to localized items, although not a major problem it can lead to lead to a more general collapse.

PantingThe tendency for the shell plate to work in and out because of fluctuating pressures on the ends of the hull when passing through waves. Additional side stringers are fitted to strengthen the areas liable to panting

Pounding Local Stresses occurring on the bottom shell framing forward when the vessel is driven into head seas. Most common when a vessel is in light ballast. Additional

Task – Revision Notes: Find the List after discharge

A vessel Δ 10300T, KG 5.2m is listed 4º to port. 742T is loaded 2.8m above the keel and is divided equally 4.58m each side of the CL. If KM is constant at 5.8m what is the final list?

Find Heeling moment= Tanº = W x D

Δ x GM

GM = KM – KG= 5.8 – 5.2= 0.6m

= Tan 4º = HM10300 x 0.6

HM = Tan 4º x 10300 x 0.6= 432.15Tm to port

Use Load table to find KG

KG = 55637.6 ÷ 11042

= 5.04GM = 5.8 – 5.04

= 0.76m

Find Heel Heel = 432.15

11042 x 0.76= 2.95º to port

Task – Revision Notes: Free Surface Effect

If a tank is completely filled with liquid then the tank effectively can be considered as a solid mass with its centre of gravity acting through the centre of the tank.If the tank is then drained to only partly filled, the surface of the liquid is free to move. The inertia causes a virtual change in the centre of gravity of the tank to some point above the theoretical centre of gravity in the tank. This effect on the ships Centre of Gravity ‘G’ will be as if the weight of the liquid in the tank where to be raised from the centre of the liquid to position of the virtual centre of gravity.

Δ KG Moment

10300 5.2 53560+ 742 2.8 2077.6

11042 55637.6

In the initial upright condition everything is pretty much normal but as the ship is heeled by an external force:

A wedge of liquid is transferred to the low side of the ship As the weight shifts G moves in parallel

This reduces the righting lever GZ and makes it the same as what the

Task – Stability Notes: GZ curves

Dynamical Stability at any angle of inclination may be defined as ‘The work required by the external forces such as wind and waves to the ship to that angle of heel.’

Transverse Statical stability is the term used to describe a ships ability to return to the upright in still water.

So for a ship heel for example 25º it is necessary for all the external forces to be over come the sum of all the righting moments.

When assessing the transverse stability of a vessel a GZ curve is drawn. GZ is the measurement of how far G and B are apart horizontally

Dynamical stability is the area under the curve, where’s statical stability just measures a horizontal line from the curve to GZ, this results in figures being the same in this case 25º & º.

We can therefore say that dynamical stability is determined by the area under the curve up to the angle of heel

This dynamical stability is measured in ‘tonne meter radians’.

Dynamical Stability will continue to increase with heel as long as there is a positive righting lever. Once it reaches the Angle of vanishing the ship will capsize. When drawing the GZ curve it is normal to draw a vertical at 53.7º which is 1 radian and a horizontal for GM on the GZ axis. Now draw a line from 0 to point where the line cross, this allows you draw the smaller angles of heel at the start of the curve.

Intact stability criteria for cargo ships with assigned freeboards under the Load Line regulations

The area under the GZ curve should not be less than 0.055 meter radians up to a 30º angle of heel, and not less than 0.09

The shaded area of the Curve represents the external forces necessary to over come the righting lever to cause the heel

meter radians up to 40º or the angle of down flooding which ever comes first

Angle of down flooding is the angle of heel at which openings in the hull / superstructure which can not be closed weather tight become immersed

The area under the righting lever curve between the angles of heel of 30º to 40º or 30º to the angle of down flooding should not be less than 0.03 meter radians.

The righting lever GZ should be at least 0.20m at an angle of heel equal to or greater than 30º

The maximum righting arm should occur at an angle of heel not less than 30º

The initial GM should not be less than 0.15m

Intact Stability requirements for Passenger ships

Passenger ships shall comply with all the same regulations as Cargo ships but in addition:

The angle of heel on account of all the passengers standing on one side shall not exceed 10º

The angle of heel on account of turning should not exceed 10º when calculated.

Intact Stability Criteria without Sails for the MSY Wind Surf

The area under the GZ curve shall not be less than 0.055mr between 0º and 30º heel

The area under the GZ curve shall not be less than 0.090mr between 0º and 40º or the angle of down flooding if less than

40º. (The angle of down flooding is the angle at which openings in the hull, superstructure and deckhouses which cannot be made weather tight become immersed.

The area under the GZ curve between heel angles of 30º - 40º (or the angle of down flooding if less than 40º) shall not be less than 0.030mr

The righting lever GZ shall be at least 0.020m at an angle of heel of 30º or greater

The maximum GZ shall occur at an angle of heel not less than 30º

The initial GM shall be greater than 0.15m

The following GZ curves demonstrate the intact stability Criteria.

GZ

57.3

HEEL

Area greater than 0.055mr

Angle greater than 0.030mr

GZ

57.3

HEEL

GZ 57.3HEEL

GZ

57.3

HEEL

Maximum GZ occurs at more than 30º

Angle greater than 0.090mr

GZ 57.3HEEL

Initial GM not less than 0.300m

GZ

57.3

Minimum 0.020m at 30º

Task – Revision Notes: Free surface effect

A vessel length 130m and beam 12m is floating upright in salt water at 4.2m draught. A deep bottom tank extends across the beam of the

vessel Length 30m, breadth 12m and depth 5m. There is a centerline division and the port side of the tank is full of oil RD 0.95KG is 4.3m Calculate the angle of list if half of the oil in the tank is pumped into the stbd tank such that the tank is level.

Find the heeling moment caused by moving the oil across the vessel

Weight of fuel = half the volume of the tank x RD oil= (5 x 30 x 6) x 0.95 = 855T

Moment = W x D = 855 x 6m (centroid of the tank is 3m from

the side)Heeling moment = 5130tm

Find Final KG

Δ = volume x density= (130 x 12 x 4.2) x 1.025= 6715.8T

Final KG Solid = 26740.44 ÷ 6715.8

= 3.98m

Find KM of the vessel= KB = half the draught = 4.2 ÷ 2

KB = 2.1m

BM = L x B 3 12

Item Δ KG Moment

Ship 6715.8 4.3 28877.94

Oil out -855 3.75 -3206.25

Oil in 855 1.25 1068.75Total 6715.

826740.44

= 130 x 123 ÷ 12 ÷ (4.2 x 12 x 130)= 2.86

KM = KB + BM= 2.1 + 2.86= 4.96

GM = KM – KG= 4.96 – 3.98= 0.98

Calculate Loss GM due to FSE

Loss GM = I x RD Δ x n2

I for tank = L x B 3 12

= 30 x 12 3 12= 4320m4

Loss GM = 4320 x 0.95 6715.8 x 22

= 0.153m

Final GM = GM – loss GM= 0.98 – 0.153= 0.827

Calculate final listTanº = w x d

Δ x GM= 51306715.8 x 0.827= 0.924= 42.7º to stbd

Task – Revision Notes: Find the Heeling moment causing the list

A vessel displacement 10000T is listed 6º to stbdKM 9.5m (constant) KG 5.52mCalculate the list and the GM after loading the following:85T at KG 6.5m and 6m to port of the CL 25T at KG 8.0m and 2m to stbd of the CL

Find Initial Heeling MomentTan 6º = w x d(hm)

10000 x 0.04Tan 6º x 10000 x 0.04 = w x d

= 462.46tm

Find final Heeling Moment85 x 6 to port = 51025 X 2 to stbd = 50

Net Heeling Moment = 462.46 + 50 -510 = 2.46tm to stbd

Find the final KG

KG = Mom Δ

KG = 55952.510110

= 5.53m

GM = KM – KG= 5.96 – 5.53

GM = +0.43m

Δ KG Moment

10000 5.52 55200+85 6.5 552.5+25 8 20010110 55952.

5

Find Final ListTanº = Heeling moment

Δ x GMTanº = 2.46tm 10110 x 0.43

List = 0.03º to stbd

Stability Notes

A vessel is said to be heeled when inclined by an external force – wind, wavesA vessel is said to be listed when inclined by an internal force – weight shifted

The centre of buoyancy moves from B to B1The centre of gravity G does not change as no weights have been movedThe righting lever GZ The Moment of Statical Stability = Displacement x GZ

Height of the Metacentre = KM KM = KB + BM

In the diagram above G is below M and the vessel has a positive GMThe vessel has a positive righting moment

Neutral Equilibrium

This vessel when heeled by an external force will remain at that angle

G and M are the same therefore GM is zeroGZ is therefore zeroRighting moment is zero

Unstable Equilibrium

This vessel when heeled over will continue to heel further

G is above M so there is a negative GMGZ is therefore negativeThere is a capsizing moment

Stiff vessels have a large GM and a short rolling period they are very stable but violent rolling could result in a cargo shift. Low center of gravity ships such as Bulk carriers

Tender vessels have small GMs and long rolling periods vessel may be barely stable and may become unstable during the voyage as G moves up due to bottom weights (fuel water etc…) being used up or if there is an increase in top weight (timber taking on water)

GZ curves

A) From the curve you can get GZ for any angle of heel. From this you can calculate the righting moment using (W x GZ)

B) Angle of vanishing stability, this is the angle at which the GZ value reduces to zero and becomes negative

C) Maximum GZD) Range of stability. This is the range of angles for which GZ is

positive, for all the angles of heel in this range the vessel will return to her initial position when the external force is removed

E) Initial GM – only really a guide as you should use the fluid GMF) Angle of deck edge immersion where the curve changes from

concave to convex

GZ

(F)

57.3

(B&D)

(C)

(E)

(A)

HEEL

GZ

HEEL

Because this area is negative we can identify this GZ curve as a curve for a vessel with an angle of loll

Loading and discharging weights

When a weight is loaded G moves in a direction directly towards the loaded weight

When a weight is discharged G moves in a direction directly away from the discharged weights position

When a weight is shifted onboard G moves in a direction parallel to the shift of the weight

The weight is moved horizontally, G moves in parallel

As the weight is suspended it acts at the derrick head, G moves vertically upwards

As the weight is swung out over the dock, G moves parallel with the move

With the weight on the dock G moves directly away from the derrick head.

Heeling due to wind age

Wind Heeling moment = windage area (m 2 ) x Distance C to B x 48.5kg/m 2

1000

Centroid of wind age area

B

Righting Mome

HEEL

Area ‘A’ Area ‘B’

Angle of down flooding

GZ x Displacement

Wind Heeling moment x 1.5

Wind Heeling moment

Area A – represents the energy developed by a combination of wind gusts and rollingArea B – represents the ability of the vessel to absorb some energy

Requirements for compliance1. Static angle of heel must be less than or equal to 0.65 x

angle of deck edge immersion2. Area B must be greater than or equal to Area A

Static angle of heel

15º roll

Stress and Bending Moment Question

A vessel has 5 equal compartments, LBP 200m each compartment being 40m. In the unloaded condition Draught = 4m and Beam is 45m We load:

1. 10000T2. 12000T3. 40000T4. 12000T5. 10000T

a) Find the maximum Shear force b) Find the maximum Bending moment

i) Find the mass of the shipDisplacement = (200 x 45 x 4) x 1.025

= 36900Tmass / m = 36900 ÷ 200

= 184.5t/m

ii) Find buoyancyWork out the total weight of the ship when loaded – weight of the cargo + displacement Buoyancy = 120900T ÷ 200

= 604.5t/m

iii) Find out the mass of the cargoHold:

1. 250t/m2. 300t/m3. 1000t/m4. 300t/m5. 250t/m

For the loading diagram 1. 604 – 250 – 184 = 1702. 604 – 300 – 184 = 120 3. 604 – 1000 – 184 = -580

4. 604 – 300 – 184 = 1205. 604 – 250 – 184 = 170

See diagram over leaf

Loading diagram

The shear force can be calculated at any point along the vessels length by calculating the area under the loading diagram

For example:

1. 170 x 40 (length of the hold) = 6800

2. 120 x 40 + 6800 = 116003. -580 x 40 + 11600 = -

116004. 120 x 40 + -11600 = -

68005. 170 x 40 + -6800 = 0

Hold 1Hold 2

Hold 3

Hold 4Hold 5

Mass /m

Length of vessel

The bending moment experienced by a vessel at any point along its length can be calculated by calculating the areas under the shear force diagram.

Because the loading diagram is made up of triangles and rectangles it is easy to calculate the area under the shear force diagram, see below

1. 20 x 6800 (half the base x the height) = 1360002. 20 x 4800 (4800 = 11600 – 6800) = 96000 + 136000 + 40 x

6800 ( area of the rectangle below it = 5040003. Etc…

Maximum Shear Forces

Bending moment is expressed in Mega Newton meters to convert tm to MNm multiply by 9.81 x 10-3

Calculating Drafts

Calculate the LCG= longitudinal moment ÷ displacement (taken from load table)

From the ships hydrostatic tables obtain:Reference keel draftMTM – moment required to trim the vessel 1mLCBLCF

Calculate the trim between perpendiculars= displacement x (LCG – LCB) ÷ MTM

Calculate the draft at the aft perpendicular = Reference keel draft – (trim x (LCF – 12) ÷ LBP)

Calculate the draft at the fwd perpendicular = Reference keel draft + (trim x (LBP – LCF +12) ÷ LBP

Calculate mid ships draft = (aft draft + fwd draft) ÷ 2

Calculating KG and GM

Calculate the vertical CofG using the load table KG = vertical moment ÷ displacement

Calculating KG corrected for free surface= KG + free surface moment ÷ displacement

From the ships hydrostatic tables using the reference keel draft obtain:= Vertical transverse metacentre KMt

Calculating the metacentric height above KGc to give GM= GM = KMt – KGc

Using the ships Max KG table obtain the Max KG for the reference keel draft.= Max KG

Calculate the margin to ensure that it is positive and therefore safe to go to sea.= Max KG - KGc

Load table will have the following titles

Description

Mass LCG Longitudinal

moment

VCG Vertical

moment

Free Surfac

e Momen

t

When plotting a GZ curve you calculate GZ by:

GZ = KN – KG x Sin Heel

The GZ figures can then be plotted against heel

KNKG x Sin

Heel Heel GZ-

0.017   0 -0.0170.909 0.7434 5 0.1656

1.82 1.4812 10 0.33882.702 2.2077 15 0.49433.559 2.91743 20 0.64165.197 4.265 30 0.9326.578 5.4829 40 1.09517.362 6.5343 50 0.82777.705 7.3871 60 0.3179

Task – Revision Notes: Synchronous Rolling and Pitching

Synchronous RollingThis occurs when the natural roll period of the vessel is the same as the arrival period of the waves

Dangers: Vessel may capsize Major structural damage Loss or shift of cargo Injury to crew or passengers Discomfort

What to do: Change courseIf unable to change course: Change speed if waves are not from the beam Change the GM – ballast or move cargo Change KM – ballast wing tanks or move cargo outboard

Synchronous PitchingThis occurs when the natural pitching period of the vessel is the same as the period of the waves.

Dangers: Damage to the bulbous bow Damage to hatches

Damages to the propeller due to cavitation Damage to the engine bearings due to the propeller racing when

it leaves the water

Task – Dry Docking

It is a requirement that all ships shall be dry docked for inspection and maintenance below the water line at periods not exceeding 2 years.When a ship is being dry docked additional forces act upon the keel, to what normally would be present due to the up thrust as result of the vessel taking to the blocks. These forces can produce excessive loads on the stern structure of the ship and can ultimately lead to a loss of stability.

When a vessel enters a dry dock she should be floated in with a small aft trim. The ship is usually aligned to the blocks with the help of a diver, once in position the dock gates can be closed and the water pumped out. The critical point for the ship occurs when the aft section of the ship touches the block, this is when a loss of stability will occur. As the water continues to fall the vessels mean draft will start to decrease as more weight is taken on the after section of the vessel, the up thrust that is given by the blocks on the stern section is known as the ‘P force’. The P force will continues to increase as the buoyancy of the vessel is lost – so basically the role of the buoyancy force, which normally would support the ship is taken by that of the P force.As more water is pumped out the vessel will become supported along its length by all the blocks this is know as the critical instant, once this occurs the problem of loss of stability is no longer such an issue and the critical period is over, when this occurs the P force acts uniformly

along the vessels length – this force continues to increase as the buoyancy is further reduced. Once the ship is fully dry i.e. the blocks are supporting the full ship the P force will be equal to that of the vessels displacement.

It is possible to calculate the P force at any time during the operation

P force is calculated using the following formulae

P force = Reduction in True Mean Draft (cm) x TPC

During the critical period prior to the bow section taking to the blocks the P force will be acting on a single point on the stern frame of the ship. This stern frame is specially designed and strengthened for this purpose – but for obvious reasons there is only so much force that this frame can take. If this limit is exceeded structural damage to the stern frame will occur. The easiest way to avoid damage to the stern frame from too higher P force is to limit the aft trim; this is because P force is directly proportional to the change in trim so therefore if you keep the trim to a minimum then the maximum load experienced by the stern frame will also be decreased. It is therefore fair to say that the bigger the vessels displacement the more important it is to keep the trim to a minimum.

Task – Revision Notes: Trim and Stability

Trim is also known as Longitudinal Stability and it is measured as in changes in draft rather than in degrees.

When the vessel is on an even keel G and B are in a vertical line and the ship will be displacing its own weight in water. If a weight is moved aft of the center of flotation the center of gravity will also move aft, the ship will now trim until G and B are once again vertical.

Water density changeWhen a ship passes from one density water to another the mean draft will change. If the ship is heavily trimmed the trim will change also. As it passes from say sea water into fresh water the ship will sink down due to being in denser water and the Center of gravity changes causing B to move so it is once again vertically below G and once again in Equilibrium. This in turn will cause a change in trim.

Loading If a cargo is loaded at the center of flotation there will be no trimming moment and the drafts will increase uniformly

If the weight is now shifted fwd / aft of the center of flotation it will cause the vessel to trim.

Trim and stability booklet With every new ship a trim and stability book is produced, it contains the following:

Ships particulars Inclining experiment report and results Capacity, VCG, LCG and particulars for all holds, tanks etc… Deadweight scale data Hydrostatic curves Example conditions

o Lightweighto Full loado Heavy ballasto Medium ballasto Light ballast

All these criteria can be built around a computer which will allow the Officers to input data before loading or discharging to ensure that the all stability criteria are met first.

Stability change during floodingWhen a compartment is bilged the mean draft will increase. The change in mean draft causes a change in the position of the center of buoyancy and the initial metacentre. KM changes but KG remains constant, GM changes also.

PermeabilityPermeability is the percentage of space which can be occupied by water when a space is flooded.