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Intact Stability Calculation

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0 General Particulars

Name of Vessel : 25 Meter Hydrographic Survey Vessel

Owner : BIWTA

Type of Vessel : Survey Vessel

1 Principal Particulars & Dimension

Particulars

Length Overall 25.0 Meter

Length of Hull 25.0 Meter

Breadth 06.5 Meter

Depth 03.0 Meter

Engine 02X300 hp

Maximum Speed 12.5 Knots (Full Load, 100% MCR)

Cruising Speed 11 Knots (Full Load, 90% MCR)

Fuel 9000 Liter

Fresh Water 1500 Liter

Grey Water 300 Liter

Waste Water 300 Liter

Lightship 59.60 Tonne

Full Load Displacement 71.31 Tonne

Draught at Lightship 0.97 Meter

Draught at Full Load 1.15 Meter

Generator 02X38 kVA

Endurance 2000 nm @ Cruising Speed

2 Nomenclature

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AP Aft Perpendicular

BG Longitudinal distance between Center of Buoyancy and Center of Gravity0 Height of Initial Metacenter above Center of Buoyancy in transversecondition Displacement in metric tons (t)

LOA Length overall of shipLBP Length between perpendiculars.

B Breadth Moulded Block Coefficient Prismatic Coefficient Midship Coefficient Water Plane CoefficientD Depth

d Mean draft from Base Line

FSC Free Surface correction

GM Transverse metacentric height (m)

GZ Righting lever (m)LCB Longitudinal center of Buoyancy

LCF Longitudinal center of floatation

VCB Vertical center of buoyancy over base line (m)

LCG Longitudinal center of gravity from aft end or mid ship

VCG Vertical center of gravity over base line (m)

KG Same as VCG

KB Same as VCB

KG KG corrected for free surface effects (m) Longitudinal metacentric height (m) Transverse metacentric height (m)

Angle of heel (deg.)MCT Moment to change trim one cm (t-m/cm).

TPC Tons per cm immersion

WS Wetted Surface Area (m2)

3 Stability Criteria Applied

General

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The vessel was evaluated by the rules & guidelines set by IMO A.749(18) Ch3 (Code for

Intact Stability & Design Criteria Applicable to All ships).

4. Brief description of Stability Criteria

1. Minimum requirements for stability of Inland Ships

Except Barge, Pontoon and floating equipments, all ships, having length greater than 24

meters should comply with any one standard between the following two standards at any

loaded conditions.

Standard 1

The area under the GZ curve is not to be less than 0.055 m-radian heeling angle up

to 300 and not less than 0.09 m-radian for the heeling angle 400 or the angle of

flooding which one is less. Beside the area under the curve of GZ is not to be lessthan 0.03 m-radian at the heeling angle 300 and 400 or if the angle of flooding at

300 is less than that of 400.

GZ is to be at least 0.20 m at an angle of heel equal to or greater than 300.

The heeling angle is to be not less than 250, at which GZ is maximum.

The initial metacentric height must not be less than 0.15 m for L>70 m and is to be

not less than 0.35 m for L= 70 m and is to be

not less than 0.35 m for L< 70 m.

The highest righting lever should occur at the heeling angle greater than 150.

The Effect of Free Liquid Surface

For the free surface liquid surface effect, the initial metacentric height and GZ curves should be

corrected as per following assumptions.

The free surface must be considered for liquid in tanks including ballast water tank for identifying

the effect of liquid on stability.

Tanks should be either empty or full as far as possible.

For identifying the correction of free surface, those tanks should be considered which are able to

create the maximum free surface moment

can be calculated for each tank by the following formula =

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Where, = free surface moment (meter-ton) = total capacity of tank = molded breadth of tank = Specific weight of tank liquid, ton/

3

= block coefficient of tank = h = molded depth of tank

l = maximum length of tank in meter

k = coefficient from the following table as per b/h ratio

Table of Coefficient K

b/h 5 10 15 20 30 40 50 60 70

10 0.01 0.11 0.12 0.12 0.11 0.1 0.09 0.07 0.05

5 0.04 0.07 0.1 0.11 0.11 0.11 0.1 0.08 0.05

3 0.02 0.04 0.07 0.09 0.11 0.11 0.1 0.09 0.08

2 0.01 0.03 0.04 0.06 0.09 0.11 0.11 0.1 0.09

1.5 0.01 0.02 0.03 0.05 0.07 0.1 0.11 0.11 0.11

1 0.01 0.01 0.02 0.03 0.05 0.07 0.1 0.12 0.13

0.75 0.01 0.01 0.02 0.02 0.04 0.05 0.08 0.12 0.15

0.5 0 0 0.01 0.01 0.02 0.02 0.05 0.09 0.016

= sin12 (1 + 2

2 )

= cos8 1 + tan

cos

12()2

(1 + 22

)

Where, cot