BAB I

CHAPTER I

INTRODUCTION

1. General

The lines plan (lines drawing) consist of projections of the intersection of the hull with a series of planes. The planes are equally spaced in each of the three dimensions. These set of planes are mutually perpendicular or orthogonal in nature.

The point of intersection of these planes with the hull results in a series of lines that are projected onto a single plane located on the front, top, or side of the ship. This results in three separate projections, or views, called the Body Plan, the Half-Breadth Plan, and the Sheer Plan.

To visualize, place the ship in an imaginary rectangular box whose sides touch the keel and sides of the ship. The bottom, side and front of the box will serve as the basis for three orthogonal projection screens on which lines will be projected onto. The lines to be projected result from the intersection of the hull with planes that are parallel to each of the three orthogonal planes mentioned.

Making a lines plan can be applied with some methodes, for example Maxsurf, Scheltema de here methode, and NSP methode. The NSP methode is a methode which uses a diagram to knows the areas of each station. The ships length and velocity value are the first data needed. This methode lets us know each Block Coefficient (Cb) value, Prismatic Coefficient (Cp) value, and Midship Coefficient (Cm) value.

To use NSP diagram, calculate the speed length ratio first. Then create a horizontal straight line from speed length ratio value so we will know each Block Coefficient (Cb) value, Prismatic Coefficient (Cp) value, and Midship Coefficient (Cm) value.

2. Working Steps

The beginning data calculation

CSA-making

Creating A/2T and B/2

Creating Bow and Stern Curve

Creating Body Plan

Creating Half Breadth Plan

Creating Sheer Plan

Creating Forecastle Deck, Poop Deck, and Bulwark

It used some softwares; Microsoft Office Excel 2010 for data calculation and AutoCAD 2007 for drawing the Lines Plan

GlossariesPict I.3.1. Stretch Ship Length between Perpendicular (LPP)

The distance between the aft perpendicular (AP) and the forward perpendicular (FP)

Aft Perpendicular (AP)

The plane (or line) perpendicular to the load waterline that passes through the rudder stock is the aft perpendicular. In case of ships without rudder stock a vertical passing through the intersection of the waterline with the stern is taken as the aft perpendicular. A point to be noted is that once the perpendicular is fixed, the perpendicular does not change with conditions where the waterlines might change.

Forward Perpendicular (FP)

The plane (or line) perpendicular to the load waterline that passes through the intersection of stem and this waterline is the forward perpendicular. Again once the perpendicular is fixed, it does not change with various waterlines.

Length of Water Line (LWL)The overall length of the waterline from stem intersection to the stern intersection. It is usually referred to a particular waterline, however, if not mentioned it usually means at the load waterline. This length is used for most hydrodynamic calculations where the underwater dimension is relevant.

Length Overall (LOA)

The total length of the ship including plate thickness, fender or bulwark, i.e., from aft extreme end to the forward extreme end.

Pict I.3.2 Athward ShipBreadth (B)

The distance of inter ships side measured at the midship.

Breadth Overall ( BOA)

It is the extreme dimension from side to side of the ship, usually in the midship region, including the plate thickness, fender, e.t.c

Depth/ Height (H)

The depth of the hull is the distance from the keel to the deck. If the deck is cambered, or curved, the depth may be defined as the distance from the keel to the deck at the intersection of the deck and side including thickness of both keel and deck.

Draught (T)

The distance from the keel to the surface of the water. The mean draught is the draught at amidships.

Chamber

The rise or crown of a deck, athwartship. It is also called round of beam.

Block Coefficient (Cb)

The block coefficient gives the ratio of the volume of the underwater body (volumetric displacement) and the product of rectangular beam spanned by length between perpendicular(L), breadth moulded(B), and draft(T). A vessel with small block coefficient is referred to as slim. In general fast ships have a small block coefficient.

Pict I.3.3 Block Coefficient

Prismatic Coefficient (Cp)

Prismatic coefficient (Cp) is the volume (V) divided by Lpp x Am. It displays the ratio of the immersed volume of the hull to a volume of a prism with equal length to the ship and cross-sectional area equal to the largest underwater section of the hull (midship section).

Pict I.3.4 Prismatic Coefficient

Midship Area Coefficient (Cm)

One of the coefficients of fineness.It is the ratio of underwater are of midship section to that of the circumscribing rectangle.

Pict I.3.5. Midship Area Coefficient

Midship Area (Am)

Midship Area is an area of midship. Look at Pict I.3.5. Midship Area si the hatch area one.

Displacement Volume ()

Displacement Volume is the volume of water displaced by the hull.

= Lwl . B . T . CbCentreline

The middle line of the ship,extending from stem to stern at any level.

Baseline

A fore-and-aft reference line. On large vessels it is at the upper surface of the flat plate keel at the center line. Vertical dimensions are measured from a horizontal plane through the baseline, often called the molded base line.

Station

Planes parallel to the front and back of the imaginary box are called stations. There are three important stations. The intersection of the stem of the ship at the design water line is called Forward Perpendicular (FP). The intersection of the stern at design waterline(immersed transom) or the rudder stock is called the Aft Perpendicular (AP). The station midway between the perpendiculars is called the midships stations.

Pict I.3.6. Station

Body Plan

Each station plane will intersect the ship's hull and form a curved line at the points of intersection. These lines are called sectional lines and are all projected onto a single plane called the Body Plan.

Pict I.3.7 Body Plan

The body plan takes advantage of the ship's symmetry. Hence only half the section is show; the sections forward of amidships are drawn on the right side, and the sections aft of the amidships are drawn on the left side. The amidships section is generally shown on both sides of the body plan.

Half Breadth Plan

The bottom of the box is a reference plane called the base plane. The base plane is usually level with the keel. A series of planes parallel and above the base plan are imagined at regular intervals, usually at every meter. Each plane will intersect the ship's hull and form a line at the points of intersection. These lines are called waterlines and are all projected onto a single plane called the Half-Breadth Plan.

Pict I.3.8 Water lines and Half Breadth Plan

Each waterlines shows the true shape of the hull from the top view for some elevation above the base plane. The water lines referred to here has nothing to do with where the ship actually floats. There waterlines are the intersection of the ship's hull with some imaginary plane above the base plane. Since ships are symmetric about their centerline they only need be drawn for the starboard or port side

Sheer Plan

A plane that runs from bow to stern directly through the center of the ship and parallel to the sides of the imaginary box is called the centerline plane. A series of planes parallel to one side of the centerline plane are imagined at regular intervals from the centerline. Each plane will intersect the ship's hull and form a curved line at the points of intersection. These lines are called buttock or butt lines and are projected onto a single plane called the Sheer Plan.

Pict I.3.9 Buttock Lines and Sheer Plan

Each buttock line shows the true shape of the hull from the side view for some distance from the centerline of the ship. The centerline plane shows a special butt line called the profile of the ship.

Curve of Section Area ( CSA)

The sectional area curve represents the longitudinal distribution of cross sectional area below the DWL. The ordinates of a sectional area curve are plotted in distance squared units. Inasmuch as the horizontal scale, or abscissa, of Figure above represents longitudinal distances along the ship, it is clear that the area under the curve represents the volume of water displaced by the vessel up to the DWL, or volume of displacement.

Pict I.3.10 Curve of Section Area

NSP Diagram

Pict I.3.11 NSP Diagram

NSP diagram is used to make CSA. To use it, Vs/L value must be known first (L in feet). After the Vs/L value found, make a horizontal straight line from Vs/L value to the continuous right side. Then the value of , , and will be found. Sheer

Sheer is the rise of deck from amidships towards the bow and stern. Standard sheer has a calculation. First, the LPP must be devided by 6 parts. 3 parts in front of amidship, and 3 others behind amidship.

Pict I.3.12 Sheer Making

Sheer standrd calculation :

Forecastle Deck

Forecastle is a superstructure fitted at the extreme forward end of the upper deck. It has 2.4 - 2.5 m height from upper deck side line. Its length is up to reach the collision bulkhead or 5% - 8% Lc and placed at the frame.

Pict I.3.13 A Bow Ship

Poop Deck

Poop deck is a super structure or deck at the after end of the ship above the main deck. It has 2.4 - 2.5 m height from upper deck side line equal to the forecastle deck height. Its length is up to reach the engine room bulkhead.

Pict I.3.14 Stern Deck

Bullwark

Bulwark is fore and aft vertical plating immediately above the upper edge of the sheer strake. It has 1 meters height from the deck below. The function of bulwark is to prevent the water entered to the ship and prevent the crew or passanger fail over board.

Pict I.3.15 Bulwark

Collosion Bulkhead, Sterntube Bulkhead, Engine Room Bulkhead, and Bulwark Rules

The position of Collision Bulkhead, Sterntube Bulkhead, and Engine Room Bulkhead are not at the station, but they are at the frame number.

Stern tube bulkhead as frame number 0.

The distance of the sterntube bulkhead to the end of stern is not to be less than 3 frame spacing (frame space 600 mm)The length of engine room is depended by the engine size.(frame space 1000 mm)If the accommodation room is on the poop deck, the engine room bulkhead is should be at 17% - 20% LPP from AP.

The collision bulkhead is located at 0.05 - 0.08 Lc from FP. Lc is 96% Lwl or equal to LPP at 0.85 H, Lc value is the bigger one.

Frame spacing at the cargo hold is a0 = L / 500 + 0,48 [m], where a0 is not to be greater than 1000 mm. CHAPTER II

WORKING STEPS AND CALCULATION

The Beginning Calculation

1.1 Determine The Type and Size of Ship

Determining a dimension of ship can be done by compare a comparator ship. The comparator ship is selected by reference the type and size of ship. This assignment is used Container Cargo for the ship type and the size is 1700 - 2000 TEUs. The data of the comparator ship is obtained from NkClass website. The data of the comparator ship as follows,

Type : Container Carrier

Ships Name : AYUTTHAYA BRIDGE

Year of Build : 2007

GT : 17.211 tonEngine type : KAWASAKI HEAVY INDUSTRIES, LTD, 2 SA 7 CY

DWT : 21.992 tonPower : 25.270 KW

Lpp : 160,96 mRPM : 105

B : 27,6 mSevice Speed (Vs) : 20 knot

H : 14 mSea Trial Speed (Vt) : 21,6knot

T : 9,517 m

Table II.1.1 Data of Comparator Ship

Based of the data above, the designed ship data is follows,

TypeCONTAINER CARRIER

Lpp163,9 M

Breadth (B)30 M

Depth (H)14 M

Draugth (T)8,1 m

Service Speed (Vs)20 Knot

Table II.1.2 Data of Designed Ship

1.2 Using NSP Diagram

The first steps to using NSP diagram is knows the value of speed length ratio. To get the speed tength ratio, service speed (Vs) and length of displacement (Ldisp) value are needed. After speed length ratio value is obtained, the Cb, Cp, and Cm value will be known. The detailed steps using a NSP diagram are below.

Determining Length of Waterline

Length of Waterline (Lwl) can be determined by

Lwl = Lpp + x . Lpp

Where x is not less than 1% and not gtreater than 5%

1%