Lg Ecsu Nasc 170413

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ECSU(M&S)/ Control Operation of Ship NASC/Vers.No.1/April 2013 1

To Be A World Class Maritime Academy

LEARNING GUIDE

Name of Course : Combined Chief and Second

Engineer 3000 kW or more

Unlimited Voyage

Course Code : ECSU

Module : 4

Subject : Controlling the Operation of the

Ship and Care for Persons on

board (NASC)

Instructional Hours

Lecture : 75 hours

Practical : 0 hours

Tutorials : 25 hours

Total Contact Hours : 100 hours

Self Learning : 70 hours

Total Hours : 170 hours

Entry requirements

Watch keeping Engineer 750 kW or more

Subject Aims

The Module provides an understanding of the principles that maintain the

stability of ocean going ships under various conditions of cargo loading and

seaway. The module also provides an understanding of the design and

constructional aspects of ships with reference to effective maintenance.

Teaching Methods

The course shall be conducted in a combination of classroom lectures,

practical hands-on exercises, and self-learning.

Assessment Methods

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Lecturers’ Class Assessment : 20%

Mid Course Test : 30%

Final Exam : 50%

Recommended Texts

1. E.C. Tupper, INTRODUCTION TO NAVAL ARCHITECTURE

(2004), Butterworth Heinemann, ISBN: 0-7506-6554-8.

2. E.A. Stokoe, REED’S NAVAL ARCHITECTURE FOR MARINE

ENGINEER (VOL.4) (2003). Reed’s Marine Engineering Series

3. E.A. Stokoe, REED’S NAVAL ARCHITECTURE FOR MARINE

ENGINEER (VOL.5) (2003). Reed’s Marine Engineering Series

4. D.J. Eyres, SHIP CONSTRUCTION 5TH. EDITION (2001).

Butterworth-Heinemann

5. Rawson. KJ, Tupper. EC, BASIC SHIP THEORY, VOLUME 1

(2001), Elsevier Butterworth-Heinemann,

6. Derret , Barrass DR, Dr C B, SHIP STABILITY FOR MASTERS

AND MATES (1999), Elsevier Butterworth-Heinemann,

7. Watson. DGM, PRACTICAL SHIP DESIGN (1998) , Elsevier

Butterworth-Heinemann,

8. House. DJ, SEAMANSHIP TECHNIQUES 2ND

EDITION (2001) ,

Elsevier Butterworth-Heinemann,

9. Schneekluth. H, Bertram. V, SHIP DESIGN FOR EFFICIENCY

AND ECONOMY 2ND

EDITION (1998) ,Butterworth-Heinemann,

10. www.imo.org

11. www.imarest.org

Table of Specifications

Topics Weightage%

Total K U A I

A Movement of the Centre of

Gravity 2 1 0 3

B Floatation 1 1 0 2

C Transverse Statical

Stability 2 1 0 3

D Effects of liquids on

Stability 1 1 0 2

http://www.imo.org/

http://www.imarest.org/

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E Correcting an Angle of

Loll 1 0 0 1

F TPC and Displacement

Curves 1 0 0 1

G Forms Coefficients 1 0 0 0 1

H Areas and Volumes of

Ship’s Shapes 1 0 0 1

I KB, BM and Metacentric

Diagrams 2 1 0 3

J Lists 1 1 0 2

K Moment of Statical

Stability 1 2 0 3

L Trim 2 2 0 4

M Dry-Docking and

Grounding 2 1 0 3

N Damage Control 2 1 0 3

O Rudders 2 1 0 3

P Resistance, Powering and

Fuel Consumption 2 3 0 5

Q Propulsion and Propellers 2 1 0 3

R Hydrostatics 1 0 0 1

S Damage Control on Hull 2 1 0 3

T Ship Motions 1 1 0 2

U Vibration in Ships 2 1 0 3

V Rudder Theory 2 1 0 3

W Propulsion and Propellers

Theory 3 1 0 4

X Ship Structures -

Definition of terms 1 0 0 1

Y Ship Types 0 1 0 1

Z Forces on the hull 2 1 0 3

AA Distortion of the hull 2 2 0 4

AB Materials 3 2 0 5

AC Keel and bottom

construction 1 1 0 2

AD Shell and Deck

Construction 1 1 0 2

AE Bulkheads 3 2 0 5

AF Bow and Stern

Construction 1 0 0 1

AG Seatings 1 0 0 1

AH Tanks 1 0 0 1

AI Tankers 2 1 0 3

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AJ Liquefied Gas Carriers 2 1 0 3

AK Liquefied Petroleum

Tankers 2 1 0 3

AL Surveys 2 2 0 4

AM Bow Thrusters 1 1 0 2

Total 1 61 38 0 100

Main Objectives

Movement of the Centre of Gravity

At the end of the course, the learner should be able to:

1. Explain the effect of removing, adding, shifting and suspending

masses on the center of gravity of the floating body

Floatation

1. Explain Tonnes per Centimetre Immersion (TPC)

2. Explain how different densities of water affect the TPC

3. Compare the effect of a change of density on draught, when the

displacement remains unchanged, for a box-shaped and a ship-

shaped vessel

Transverse Statical Stability

1. Explain and describe stable, neutral and unstable equilibrium

stability

2. Describe the stability of a ship at an angle of loll

3. Describe the danger of a ship having a negative GM

Effect of Liquids on Stability

1. Describe and explain the effect on stability when a tank is full

filling of liquid

2. Describe and explain the effect on stability when a tank is partially

filling of liquid

Correcting an Angle of Loll

1. Explain the factors that contribute to list due to negative

metacentric height (GM)

2. Describe the process correcting negative GM

TPC and Displacement Curves

1. Utilize TPC (tonne per centimeter immersion) vs draught curves to

find mean draughts when masses are added and discharged

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Form Coefficients

1. Define the coefficient of fineness of water plane area, block

coefficient and midship coefficient

Areas and Volumes of Ship Shapes

1. Apply the Simpson’s 1st, 2

nd and 3

rd rules which may be used to

determine:

a. Areas and volumes of ship shapes, hulls, tanks, etc.

b. Positions of centroids and the center of gravity of

homogeneous masses

c. First and second moments of both area and volume

KB, BM and Metacentric Diagrams

1. Determine values of KB for box-shapes vessels and understand

how the expression for transverse BM is obtained

2. Describe the effect of draught and beam on KM.

Lists

1. Describe the sequence of events when a mass is moved transversely

and a vessel takes on a list.

2. Describe briefly the principle of the inclining experiment.

Moment of Statical Stability

1. Explain the moment of statical stability and the concept of

dynamical stability

2. Describe how dynamical stability can be obtained from a curve of

statical stability

3. Explain why the Load Line Rules specify minimum areas under

curves of statical stability in order to ensure satisfactory stability.

Trim 1. Describe the effect of trim on tank soundings.

2. Solve problems related to the quantity of fluid required to fill a

partially filled tank when a ship is trimmed.

Dry-docking and Grounding

1. Describe the procedures for dry-docking,

2. Explain the forces acting on the ship in dry-dock and during

grounding.

Damage Control

1. Explain the effects of flooding of a compartment, and IMO

requirements on floodable length

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2. Explain why damage to compartments may cause a ship to sink as a

result of:

a. Insufficient reserve buoyancy, leading to progressive

flooding

b. Progressive flooding due to excessive list or trim.

c. Capsizing due to loss of stability structural failure

3. Effect of flooding on transverse stability

4. Effect of flooding on trim

Rudders

1. Explain the variables which affect the force on a rudder.

2. Identify the location of the center of pressure of a rectangular

rudder

Resistance, Powering and Fuel Consumption

1. Explain what is meant by wave-making, frictional resistance, form

drag and form, eddy-making, air resistance (and compares it to the

total water resistance) and appendage resistance (and compares it to

the total resistance of the hull)

2. Describe the relationship between frictional resistance and ship

speed; the wetted area; the surface roughness; the length of the

vessel

3. Explain that, within ship’s operating speed range, fuel consumption

per unit time will be directly proportional to the power developed.

Propulsion and Propellers

1. Describe briefly how the power of a propulsion turbine is

measured.

2. Derive hull and propeller efficiency

3. Describe the fundamental principle of a propeller

4. Explain how the propeller action creates a reduction in pressure on

the after part of the hull

Hydrostatics

1. Explain center of pressure and establish that the center of pressure

is always below the centroid of the wetted area

2. Calculate the forces at the bottom and top of rectangular bulkheads

when compartments are flooded on one side and two sides, but no

different heights

Damage Control on Hull

1. Explain emergency action following hull damage

2. Explain possible repairs to hull damage.

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Ship Motion

1. Name and explain the six degrees of freedom of a ship.

2. Explain that large rolling angles will occurs if a wave frequency

synchronizes with the natural rolling period of the ship.

3. Describe the passive and the active methods used to reduce rolling

Vibration in Ships

1. Describe local vibration.

2. Discuss how local vibration might be overcome.

3. Describe the normal sources of vibration

4. Explain what is meant by synchronous or resonant vibration.

Rudder Theory

1. Explain the considerations, which govern the size and shape of a

rudder.

2. Explain how a rudder is located and supported vertically and

transversely

Propulsion and Propellers Theory

1. Explain the basic terminology of propeller,

2. Explain working principle of propeller and appreciate the various

problems encountered by propellers

Definition of terms

1. Explain the various terminologies used in Naval Architecture and

be able to appreciate their significance.

Ship types

1. Understand the design features of various types of ship (passenger,

general cargo, tanker, container, roll on roll off, liquefied gas tanker

and bulk carrier), their general layout, and able to sketch their

cross- section showing the principal structural features

Forces on the hull

1. Explain the various static and dynamic forces acting on the ship

structure

2. Sketch/construct typical weight curve, buoyancy curve, load curve,

shear force and bending moment diagrams

Distortion of the hull

1. Describe the bending moment of a ship

2. Explain its effect on ship structure and the stresses acting on the

ship structure and their related components

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Materials

1. Explain the materials used for ship construction

2. Explain the corrosion problems encountered and the methods

employed to prevent corrosion on hull plating

Keel and bottom construction:

1. Describe the different types of keel construction in general use.

2. Describe the double bottom construction of a ship and the framing

system for a container ship, oil tankers, under machinery and the

pounding region

Shell and Deck construction

1. Describe the shell and deck design features of a merchant ship and

2. Explain the requirements related to any openings in these structures

Bulkheads

1. Explain the purpose of a bulkhead, its construction, strength and the

necessary compensation for penetrations through the bulkhead

such as watertight doors, gas tight doors, pipes, electrical cables,

and air trunking

Bow and Stern construction:

1. Describe the construction of bow and stern structures

2. Explain the principal stresses experienced by them.

Seating

1. Describe the construction of seating for deck

2. Describe engine room machinery and valves

Tanks

1. Describe the design features of a deep tank, and its purpose.

Tankers

1. Describe the design features of tankers.

Liquefied Gas carriers

1. Describe the design features of liquefied natural gas carriers.

Liquefied Petroleum Gas tankers

1. Describe the design features of liquefied petroleum gas carriers.

Survey

1. Explain the various requirements of surveys, and the items to

inspect during survey

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Bow Thrusters 1. Describe the design features of thrusters

Study Guide

Students are advised to pay particular attention to following reference

material listed under “Recommended Texts” over and above the notes that

will be provided during lectures.

1. Tupper. EC, INTRODUCTION TO NAVAL ARCHITECTURE 4th

EDITION (2004), Elsevier Butterworth-Heinemann

Floatation

a. Equilibrium of a floating body - Ch.5, Pg.63

Transverse Static Stability

a. The concept of the ship stability at small angle - Ch.5, Pg.66

The concept can be explained by considering it to be inclined

from the upright by an external force which is then removed.

The focus is on the concept of ship stability at small angle.

b. Ship stability standard - Ch.7, Pg.116

Special attention is focused on transverse stability of intact and

damage condition

Effect of Liquids on Stability

a. The effect of liquid free surfaces - Ch.5, Pg.81

Study and understand the series of equation of effect of

partially filling liquid cargo which are explained with

assumption of quasi-static condition.

Correcting Angle of loll

a. The effect of negative metacentric height - Ch.7, Pg.108

When the angle of inclination is greater than 4 or 5 degrees the

metacentric point can not longer be regarded as fixed point.

When the ship has negative GM, there would be a position of

unstable equilibrium. Study and understand this concept

Form Coefficient

a. Ship form calculation - Ch.4, Pg.49

Three dimensional hull forms can be represented by a series of

curves with three sets of orthogonal planes. The focuses are on

the formula of form coefficient and the methods to solve the

areas and volumes enclosed by the curves and surfaces.

KB, BM and Metacentric Diagram

a. The concept of transverse metacentric - Ch.5, Pg.68

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The concept and example of transverse metacentric for simple

geometrical forms are addressed. Full understand and able to

solve the problem related the position of metacentric is

essential

b. Metacentric diagram - Ch.7, Pg.71

The positions of B and M have been seen to depend only upon

the geometry of the ship and the draughts at which it is floating.

Study and understand the metacentric diagram and the factors

govern it.

Lists

a. The inclining experiment - Ch.5, Pg.84

The inclining experiment is experiment that causing the ship to

heel to small angles by moving known weight known distances

transversely across the deck and observing the angles of

inclination. Study and understand the concept of inclining

experiment.

b. Stability at large angle - Ch.7, Pg.104-117

The stability for larger disturbances is considered. Study and

understand the stability for larger disturbances.

Trim

a. Principle of trim - Ch.5, Pg.72

Placing a small weight anywhere along the length can be

regarded as being initially placed at center of floating (F) to

cause sinkage and the moved to its actual position, causing

trim. Study and understand the principle of trim.

Dry Docking and Grounding

a. Procedure for docking - Ch.8, Pg.133

The ship must be allowed to ground on the dock floor without

damage. It is essential to know about general docking plan.

b. Stability when docking - Ch.8, Pg.137

When a ship is partially supported by the dock blocks, its

stability will be different from that when floating freely. Study

and understand the stability when docking

c. Factors influence the extent of damage during grounding -

Ch.8, Pg.139

The value of forces of grounding depends on these values.

d. Stability on grounding - Ch.8, Pg.139

Study and understand the stability on grounding

Damage Control

a. Flooding and damage stability - Ch.7. Pg.118

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The flooding will cause the ship to founder or capsizing. Any

flooding can cause a reduction in stability that might end with

capsize. If the reduction does not cause capsize it might lead to

angle of heel to launch the lifeboats. Study and understand the

stability when she is flooded.

Rudder

a. Type of rudder - Ch.13, Pg.261

This topic reviews briefly some of common rudder types.

b. Forces acting on rudder - Ch.13, Pg.267

Explanation of forces acting on conventional type of rudder

only is to be understood.


a. The principle of ship resistance - Ch.9

When a body moves through a fluid it experiences forces

opposing the motion. As a ship moves through water and air it

experiences both water and air forces. Unless the winds are

strong the water resistance will be dominant factor in

determining the speed achieved.

Propulsion and Propeller

a. The principle of the propulsion system - Ch.10

This topic reviews the driving forces of the ship and the

interaction between the propulsor and the flow around the hull.

Ship Vibration

a. Ship dynamic - Ch.11, Pg.219

In the reality ship is a flexible structure subject to many

fluctuating forces. It is useful to set the scene by describing

briefly the basic response of an elastic system to applied forces.

2. Smith. R Munro, ELEMENT OF SHIP DESIGN (1975), Marine

Management (Holding) Ltd

Statical Stability

a. Stability - Ch. 2, Pg. 8,61

The principal of ship stability and its criteria are addressed.

Form Coefficient

a. Slimness coefficient - Ch. 5, Pg. 53

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It is listed the definition of hull geometry and certain

coefficients which are guides to the fullness or the slimness of

the hull and which are useful criteria with which to compare

one ship with another.

Survey

a. Classification and specifications - Ch.8

Many hazard of the sea depends upon the structural fitness of

the ship. The classification society is the reliable organizations

for the inspection and maintenance of the fitness of merchant

ships.

Damage Control

a. Freeboard, subdivision and tonnage - Ch.9

Propulsion and Propeller Theory

a. Powering and Propellers - Ch.11

3. Stokoe. EA, REED’S NAVAL ARCHITECTURE FOR MARINE

ENGINEERS VOL.4 (2003), Reed Publication

Movement of Center of Gravity

a. Shifting of center of gravity - Ch.4

The effect of removing, adding, shifting and suspending

masses, on the center of gravity of a floating body are explained

by problem examples.


a. The ship stability at small angle - Ch.5

The concept of statical stability, three types of stability

equilibrium and problem examples are presented.

TPC and Displacement

a. The displacement of the ship - Ch.2, Pg.20

b. Tonne per Centimeter Immersion TPC - Ch.2, Pg.22

The curves of TPC at different draught are shown and

explained.

Form Coefficient

a. The coefficient of form - Ch.2

The relation between the form of the ship and the dimension of

the ship are known as coefficient of form. The coefficients of

form are described.

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Lists

a. The inclining experiment - Ch.5

Inclining experiment is the simple experiment which is carried

out to determine the metacentric height and the height of center

of gravity.

b. Example of problem of ship stability at large angle - Ch.5

Trim

a. The principle of trim - Ch.6 Students must understand that trim

has an effect on the ship’s speed.

Rudder Theory

a. Principle of rudder - Ch.9 Students should be able to explain

how the turning of a vessel is achieved.

Ship Resistance

a. Principle of ship resistance - Ch.9 Students should be able to

explain that hull resistance is increased by increase in surface

roughness due to repeated painting, peeling of paints, buckling

of plates and marine growth.

4. Stokoe. EA, REED’S SHIP CONSTRUCTION FOR MARINE

ENGINEERS VOL.5 (2003), Reed Publication

Ship types

a. Ship types and terms - Ch.1

Ship types and its lay out are described.

Forces on Hull

a. Stresses in the ship structures - Ch.2

The general description of the stresses in the ship structures due

to static and dynamic load is presented. Students should

understand the concept of a beam being applied to a floating

vessel

Material

a. Section used and materials - Ch.3

The types of sections and its general dimensions are stated.

Students should be able to identify the differentiation in grades

of steel employed in ship construction.

Keel and Bottom Construction

a. Bottom and side framing - Ch.4

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The general description and layout of the double bottom and

side framing are presented. The bottom structure needs greater

strength is to be understood.

Shell and Deck

a. Shell and deck - Ch.5

The general description and layout of the shell and deck are

presented. Students should be able to understand a shell

expansion plan.

Bulkheads

a. Bulkheads and deep tanks - Ch.6

The general description and layout of the bulkheads and deep

tanks are presented. Students must also refer to SOLAS and

understand the regulations regarding construction of bulkheads.

Bow and Stern Arrangement

a. Fore and arrangement - Ch.7

The general description, layout and arrangement of the fore part

of the ship are presented. Students must understand that

bulbous bow primarily reduces the resistance due to waves.

Students should be able to explain the extra fittings like ETA

(Emergency Towing Arrangement).

b. After and arrangement - Ch.8

The general description, layout and arrangement of the after

part of the ship are presented. Students should be able to

explain the extra fittings like ETA (Emergency Towing

Arrangement).

c. Oil tankers, bulk carriers, liquefied gas carriers and container

ship - Ch.9

The general description, layout and arrangement of the oil

tankers, bulk carriers, liquefied gas carriers and container ship

are presented

5. Eyres. DJ, SHIP CONSTRUCTION (2002), Butterworth-

Heinemann

Students should read the relevant sections of this book for

understanding the regulatory aspects and Classification requirements.

This book has drawn most of the references from Lloyds.

Definition of Terms

a. Ship dimension and form - Ch.2

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The hull form of a ship may be defined by a number of

dimensions and terms which are often referred to during and

after building the vessel. An explanation of the principal terms

is given

Ship Types

a. Ship types - Ch.3

The development of various types of ship is presented

Forces on Hull

a. The stresses to which a ship is subject - Ch.8

The explanation of stresses experienced by the ship floating in

still water and when at sea is given

Keel and Bottom Construction

a. Bottom structure - Ch.16

The general description, layout and arrangement of the bottom

structure of the ship are presented.

Shell and Deck Construction

a. Shell plating and framing - Ch.17

The general description, layout and arrangement of the shell

plating and framing of the ship are presented

b. Deck, hatches and superstructures - Ch.19

The general description, layout and arrangement of the deck,

hatches and superstructures of the ship are presented. Students

should be able to explain why and how heights of hatch

coamings are varied as also the meaning of ‘excess of

hatchways’

Bulkhead

a. Bulkheads and pillars - Ch.18

The general description, layout and arrangement of the

bulkheads and pillars of the ship are presented

Bow and Stern Construction

a. Fore end structures - Ch.20

The general description, layout and arrangement of the fore end

structures of the ship are presented

b. Aft end structures - Ch.21

The general description, layout and arrangement of the aft end

structures of the ship are presented

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c. Liquefied gas carriers - Ch.23

The general description, layout and arrangement of the

liquefied gas carriers are presented

6. Ship Construction Study Guide (Additional)

Ship Motion

1. Six degrees of ship’s motion: Students should be able to

define with sketches on the six degrees of motion of the ship. These

motions are rolling, pitching, yawing, heaving, surging and

swaying. The motions of rolling, pitching and heaving are

considered serious in nature to be attended to.

2. Theory of rolling: The theory of rolling are generally

attributed to port and starboard motion of the ship. The factors that

determine these rolling motions are the metacentric height of the

ship, radius of gyration and location of masses on board. Students

should be able to discuss on the theory of this rolling phenomenon

and the factors that affect the rolling motion

3. Stabilisation of rolling motion: Students should be able to

sketch and discuss on the various devices used to stabilize rolling

motion. These devices are categorised into tank type and fin type of

stabilizers. The tank type are generally suitable for ships that are

stationary and slow moving while the fin types are suitable for high

speed application

Vibration in ships

1. Vibration terminology: Students should be able to discuss

on the meaning of vibration terminology with reference to local and

resonant vibration. Local vibration is generally generated by some

running machinery while resonant vibration is due to the

synchronization of natural and operating frequency of vibration

2. Significant of vibration: Vibration generally contribute to

discomfort of ship personnel and in severe cases, they could

contribute to crack and damages of ship structure.

3. Causes of vibration: Students should be able to sketch and

discuss on the various causes of shipboard vibration. These

vibration are due to waves, engine and propeller. The generation of

these vibration are due to slamming and pounding of ship in heavy

sea, unbalanced forces from engine, and propeller induced

vibration.

4. Mitigation of vibration: Students should be able to explain

the various methods used to mitigate shipboard vibration. The

source of the vibration must be determined before any mitigation

measures are considered. The mitigation measures could be the

changes to the ship’s course, balancing of the engine and improving

water flow to propeller or the reduction of cavitation phenomenon.

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Rudder Theory

1. Definition of rudders: Students should be able to define

with sketches on the various terminology of rudders. This include

leading edge, trailing edge, centre of pressure of rudder, and aspect

ratio

2. Rudder theory: Lift and drag forces are of utmost important

for the operation of rudder. If the lift to drag force is high, rudder

will tend to operate smoothly. Students should be able to discuss

how the generation of these forces on the rudder plate is produced

3. Construction of rudders: Students should be able to sketch

and discuss on the construction of a double plate rudder. The

construction should include all the internal framework and the tests

to be carried out after the construction. The advantages of a double

plate rudder should also be emphasized.

4. Rudder carrier bearing and rudder stock stuffing box:

Students should be able to sketch and explain the rudder carrier

bearing and stuffing box. The location and purpose of this bearing

and stuffing box should also be well understood.

5. Special rudders: The introduction of special rudders has its

great implication in the manuevring of ships Students should be

able to discuss on the advantages of these rudders in order to

appreciate the reasons behind their introduction.

6. Inspection of rudder at dry-dock: Students should be able to

discuss on the necessary inspection that need to be carried out on a

rudder. Wastage and crack on a double plate rudder must be

seriously checked and made good.

Propuslion & Propellers

1. Definition of propellers: Students should be able to define

with sketches on the various terminology of propellers. This include

leading edge, trailing edge, suction back , pressure face, propeller

boss

2. Propeller theory: The ability of producing thrust from a

propeller is generally determined by the efficiency of suction back

to pressure face of the blades surfaces. If the suction back and

pressure face surfaces are smooth and shining propeller will tend to

operate smoothly with high thrust. Students should be able to

discuss how the generation of these thrust when the propeller is

immersed in water

3. Types and configuration of propellers: Students should be

able to sketch and discuss on the various types and configuration of

propeller. The configuration of single , twin screw etc should be

________________________________________________________



well understood in term of the purpose and application. The contra-

rotating, kort nozzle and highly skew propellers also have their

main advantages for application on merchant ships. The operation

of these propellers must be well understood..

4. Singing and cavitation on propeller: Students should be

able to explain the meaning of propeller singing and cavitation. The

causes and effect of these phenomenon on propeller must be well

understood.

5. Propeller trial: Propeller trial is carried out to ensure the

performance of the propeller during actual sea condition. Students

should be able to discuss on the procedure of this trial checking on

the parameter of speed, fuel consumption and power of the engine

in relation to the propeller.

Bow Thrusters

1. Types of bow thrusters: Students should be able to describe

with sketches the various types of fixed and trainable types of bow

thrusters. The application of these thrusters on merchant ships

should be well understood.

2. Construction and operation of bow thrusters: The

construction and operation of bow thrusters are critical in order to

ensure its operation during slow movement of vessel since

manoeuvring of ships could be affected due to the ineffectiveness

of rudder at slow motion. Students should be able to discuss on the

construction of tunnel thrusters on the forward or aft of ship as well

as other types of thrusters for marine application

3. Advantages and disadvantages of thruster: Students should

be able to explain the advantages and disadvantages of thrusters

fitted to large tankers as well as other ships.

Key Questions

Naval Architecture


1. Explain the effect of removing, adding, shifting and suspending

masses on center of gravity.

Floatation

1. Explain the Archimedes’s principles.

2. Explain Tonnes per Centimetre Immersion (TPC) and how different

densities of water affect the TPC and draught when the displacement

remain unchanged.

3. Explain Fresh Water Allowance (FWA).

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1. considered a fixed point.

2. Explain stable, unstable and neutral equilibrium, as applied to a ship.

3. Explain what is meant by, and the cause of, stiff and tender ships.

4. Discuss the stability of a ship at an angle of loll.

5. Describe the danger of a ship having a negative GM.

Effects of liquids on Stability

1. Explain the effect on stability when a tank is full and partially filled

of liquid.

2. Explain the concept of free surface effect.

3. Explain the purpose of non-watertight longitudinal subdivision of

tanks.


1. State why no action must be taken related to ship stability without

written permission from responsible navigation officer.

2. State the factors that contribute to list due to negative metacentric

height (GM).

3. Discuss the process of correcting a negative GM.


1. Using given values of TPCs at different draughts, sketch a

TPC/draught curve.

2. Sketch a typical draught/ displacement curve.

Forms Coefficients

1. Define the coefficient of fineness of water plane area, the block and

midship coefficient

Areas and Volumes of Ship’s Shapes

1. Explain how Simpson’s 1st, 2

nd and 3

rd rules may be used to determine

areas and volumes of shapes, positions of centroids and the center of

gravity of homogeneous masses and first and second moments of

both area and volume.


1. Describe the effect of draught on KM.

Lists

1. Describe the sequence of events when a mass is moved transversely

and a vessel takes on a list.

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2. Describe briefly the principle of the inclining experiment.


1. Explain the moment of statical stability.

2. Describe cross curves of stability.

3. Construct typical curves of statical stability for a ship with positive

and negative initial metacentric height.

4. Describe the movement of a ship with negative metacentric height.

5. Discuss the concept of dynamical stability.

6. Explain why the Load Line Rules specify minimum areas under

curves of statical stability in order to ensure satisfactory stability.

Trim

1. Define trim.

2. Describe the effect of trim on tank soundings.

Dry-Docking and Grounding

1. Describe the required condition of a ship when entering dry-docks.

2. Describe the process of dry docking a large ocean going ship.

3. Discuss the effect on a ship’s stability when a dry dock is being

pumped out.

4. Explain the critical period during dry-docking or grounding.

5. Explain the forces on the ship’s bottom and the location of GM when

grounding takes place.

Damage Control

1. Explain margin line and permeability of space, floodable length, and

permissible length of compartment in passenger ships.

2. Describe how the position of bulkheads is determined.

3. Explain the effect of holed compartment on the ship.

4. Explain why if the lost buoyancy is greater than the reserve buoyancy

the ship will sink.

5. Explain the effect of ship’s displacement and the position of the

center of gravity when a compartment is holed.

6. Explain that the height of the center of buoyancy above the keel

increases by approximately half the increase in draught due to

flooding.

7. Describe the effect of bilging a centerline compartment located away

from amidships.

Rudders

1. Explain the variables, which affect the force on a rudder.

2. Identify the location of the center of pressure of a rectangular rudder

3. Explain the effect of ship speed on the performance of a rudder.

________________________________________________________



4. Explain, in principle, how the torque on the rudder stock is

established.

5. Explain the effect on the torque when running astern.


1. Explain what is meant by wave-making, frictional resistance, form

drag and form, eddy-making resistance, air and compares it to the

total water resistance) appendage resistance (and compares it to the

total resistance of the hull)

2. Describe the components of residuary resistance

3. Explain how ship resistance is estimated by carrying out tank tests on

models of similar form.

4. Explain why, at moderate speeds, frictional resistance may be up to

75% of the total resistance.

5. Explain what is meant by boundary layer and describes the two types

of fluid flow.

6. Describe the relationship between frictional resistance and ship

speed; the wetted area; the surface roughness; the length of the

vessel

7. Explain that there are several formulae available to determine the

wetted surface area of a ship.

8. Estimate the frictional resistance of ships of various lengths and

varying displacements at different speeds.

9. Use Froude’s Law of comparison to determine the residuary

resistance of similar ships.

10. Describe the three types of wave formed when a ship moves through

water.

11. Explain that, at high speeds, wave-making resistance may be 50 to

60% of the total resistance.

12. Explain the effect of interference of bow and stern waves.

13. Explain why ship speed and length have a major influence on the

effect of wave interference.

14. State the reasons for fitting bulbous bows.

15. Explain the effects and direction of wind speed on ship speed.


1. Explain that, within ship’s operating speed range, fuel consumption

per unit time will be directly proportional to the power developed.

2. Explain how fuel consumption per unit time is proportional to

displacement2/3

x speed3

3. Estimate potential fuel consumption and variations when running at

different speeds over repeat voyages, similar speeds on different

voyages and different speeds during a voyage

4. Describe briefly how the power of a propulsion turbine is measured.

________________________________________________________



5. Explain briefly how the power of a diesel engine is measured as shaft

and indicated power

6. Explain what is meant by delivered power

7. Describe how thrust power is determined

8. Explain what is meant by effective power.

9. Derive hull and propeller efficiency

10. Describe the fundamental principle of a propeller

11. Explain how the propeller action creates a reduction in pressure on

the after part of the hull

12. Discuss propeller slip: real slip, and apparent slip

13. Explain with sketches the following terminology of propeller: leading

edge, trailing edge, suction back, pressure face, propeller boss,

diameter

14. Sketch and explain how the generation of thrust is produced in

propeller

15. Discuss the meaning of cavitation of propeller and explain how this

phenomenon is overcome.

16. Sketch and explain the design of a high skew propeller. What is the

advantages of this propeller

17. Discuss the procedure for carrying out propeller trial to determine

speed, power and fuel consumption of the engine

Hydrostatics

1. Explain center of pressure

2. Establish that the center of pressure is always below the centroid of

the wetted area

Ship Construction

Damage Control on Hull

1. Identify the hull locations which are likely to be damaged in the event

of the vessel facing heavy seas and bad weather. Briefly suggest some

measures taken when such damages are caused

Ship Motion

1. Explain with sketches the operation of a passive tank type of stabiliser

2. Sketch and explain the operation of a folding fin type of stabiliser

3. Discuss the theory of rolling motion and identify the factors that affect

rolling motion.

Vibration in Ships

1. Justify which parts of the hull may suffer damage form hull vibration.

Suggest some measures to mitigate such damages

2. State the various sources of shipboard vibration and explain how these

vibrations could be mitigated

________________________________________________________



3. Explain the meaning of local and resonant vibration

4. Discuss the significant of shipboard vibration.

Rudder Theory

1. Explain with sketches the construction of a double plate rudder. List

down the advantages of this rudder

5. Sketch and explain a rudder carrier bearing and identify the jumping

clearance on this bearing

6. Discuss the innovation of special rudder and give an example of this

rudder.

7. Explain the inspection necessary to be carried out on a rudder when

she is at the dry-dock

8. Sketch and explain a gland packing system for a rudder stock

Propulsion and Propellers Theory

1. With reference to very large crude carriers explain the following:

a. Full power availability while going astern is inconsequential

b. Rudders are inefficient if used for retarding the speed

Definition of Terms

1. Sketch a vessel cross section and label the terms used in ship

construction

2. Define the following terms and add a line or two as notes: a. Sheer b.

Camber c. Air draught d. LBP e. LOA

Ship Types

1. Briefly explain the constructional differences between a. Container

ships b. Ore Carriers c. Oil Tankers.

Forces on hull & Distortion of Hull 1. Explain the phenomenon of hogging and sagging

2. Tabulate what loads a ship’s structure is subjected to. Differentiate

the dynamic and static loads as also universal and local loads on the

structure

3. Discuss which structural components are subjected to stresses due to

hog/sag effects.

Materials

1. Briefly discuss the types of steel employed in ship construction

explaining the alphabetical classification

2. Discuss the advantages and disadvantages of using aluminium for

ship construction

3. Illustrate with sketches the conventional method of attaching

aluminium to steel

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4. List out some composite materials which are finding usage in modern

ship construction.

Keel and Bottom construction

1. Sketch the following types of keels: a. Bar keel b. Flat bottom keel c.

Duct keel

2. Explain why a ship’s bottom plating is thicker than rest of the plates

3. Explain the construction with sketches for;

a. Transversely framed DB and

b. Longitudinally framed DB

4. Explain various types of floor arrangements

Shell and Deck construction

1. Explain the arrangement of plating on vertical and deck sections with

particular reference to butts and seams

2. Explain how ship side stiffening is achieved and the framing methods

employed.

3. Illustrate a shell expansion plan with sketches. Point out how the

frame numbering is done

4. Define: a. Stealer Plate b. Oxter Plate c. Coffin Plate

Bulkheads

1. Justify the division of a ship using bulkheads

2. Discuss the requirements for a collision bulkhead

3. Sketch a corrugated bulkhead and a corrugated section

4. Explain why water tight doors are usually located in machinery

spaces and fire doors in accommodation spaces

5. Justify the following with respect to watertight doors:

a. All fire and watertight doors can be closed/opened from either side

b. Alarms are provided for watertight doors

c. W/t doors are heavier than fire doors

d. No running grooves are provided at the bottom edge of watertight

doors

e. Sealing of watertight doors is ensured by metal to metal contact

alone

Bow and Stern construction

1. Briefly explain/define the following: a. Sole Plate b. Stern Tube c.

Dead wood d. Cant beam

2. Sketch a bulbous bow and explain its advantages

3. Sketch and label a hawse pipe arrangement

4. Sketch and label the strength members of a typical fore peak tank

5. Sketch and label a chain locker. Discuss why the chain locker survey

is critical.

________________________________________________________



6. Explain the chain locker arrangements of mud box, spurling pipe,

internal stiffening and bitter end

7. Explain the construction of a typical transom stern.

Seating

1. List typical strength components constructed under machinery

installations

Tanks

1. Sketch a deep tank arrangement and label the strength components

2. Sketch a fore peak tank with wash bulkheads. Explain how this and

other arrangements help

3. Sketch and describe a regular sounding pipe fitted on structural tanks

4. Discuss with sketches, venting arrangements provided for tanks

Tankers

1. Sketch and label a cargo tank cross section of a petroleum tanker

2. Explain why a tanker is assigned minimum basic freeboard as

compared with other ship types

3. List the additional conditions of assignment applicable for tankers

and justify the same

4. Explain the following with respect to a tanker: a. SBT b. CBT c.

COW d. IGS

Liquefied Gas Carriers & Liquefied Petroleum Tankers

1. Sketch the cross sections of: a. Prismatic tank b. Cylindrical tank c.

Membrane tank

2. With respect to gas tankers explain the significance of a ‘cold spot’

3. Describe with sketches the construction of a fully pressurized tank,

semi-pressurized/partially refrigerated tank and a fully refrigerated

atmospheric tank

Surveys

1. List down the scope of a Classification Society while surveying a ship

for seaworthiness

2. List the periodical Surveys a ship is subjected to for retaining the

class of the ship

3. Briefly elaborate four reasons for which a ship’s class may be

withdrawn

4. Enumerate the advantages of an IWS (In Water Survey)

Bow Thrusters

1. Discuss the employment of thrusters with advantages and also their

limitations

________________________________________________________



2. Briefly explain with sketches various thruster units employed on

ships

3. Explain with sketches the construction and operation of a bow

thrusters

4. Sketch and explain the operation of a ro-thruster with variable thrust

generation

5. Discuss the advantages and disadvantages of thrusters.

Additional Questions

Naval Architecture


1. Write formula of shift of the centre of gravity of the added or

removed object

2. Where is centre of gravity of a suspended weight?

3. A ship has displacement of 2400 tonnes and KG=10.8 metres. Find

the new KG if a weight of 50 tonnes mass already on board is raised

12 metres vertically.

4. A ship has displacement of 2000 tonnes and KG=10.5 metres. Find

the new KG if a weight of 40 tonnes mass already on board is shifted

from the tween deck to the lower hold. Through a distance of 4.5

metres vertically.

Floatation

1. What is water plane area of ship?

2. What is reserve buoyancy?

3. Write formula to find a new draught for a box shaped vessel

4. Write formula to find FWA

5. A ship's draft is 6.40 metres forward and 6.60 metres aft. FWA. 180

mm. Density of the dock water is 1010 kg per cu. m. If the load mean

draft in salt water is 6.7 metres, find the final drafts F and A in dock

water if this ship is to be loaded down to her marks and trimmed 0.15

metres by the stern. (Centre of flotation is amidships).

6. A ship floating in dock water of density 1005 kg per cu.m has the

lower edge of her Summer load line in the waterline to starboard and

50mm above the waterline to port. FWA= 175mm and TPC=12

tonnes. Find the amount of cargo which can yet be loaded in order to

bring the ship to the load draft in salt water.

7. Write formula to find DWA.


1. What is the maximum degrees of small heel of the vessel

2. Where the position of G and M respectively for a stable ship

3. Where the position of G and M respectively for an unstable ship

________________________________________________________



4. Where the position of G and M respectively for a neutral ship’s

stability

5. What kind of action can be taken to correct unstable and neutral

equilibrium

6. When a ship has a comparatively large GM

7. When the GM is comparatively small

8. What is a required time period that would generally be acceptable for

those on board a ship at sea.

9. Define the terms `heel', `list', ìnitial metacentre' and ìnitial

metacentric height'.

10. Sketch transverse sections through a ship, showing the positions of

the centre of gravity, centre of buoyancy, and initial metacentre, when

the ship is in (a) Stable equilibrium, (b) Unstable equilibrium, and (c)

Neutral equilibrium.

11. With the aid of suitable sketches, explain what is meant by àngle of

loll'.

12. Mention typical working values for GM for several ship-types all at

fully-loaded drafts.

Effects of liquids on Stability

1. With the aid of suitable sketches, show the effect of slack tanks on a

ship's stability.

2. A ship leaves port upright with a full cargo of timber and with timber

on deck. During the voyage, bunkers, stores and fresh water are

consumed evenly from each side. If the ship arrives at her destination

with a list, explain the probable cause of the list and how this should

be remedied.


1. A ship loaded with timber and with timber on deck, berths with an

angle of loll away from the quay. From which side should the timber

on deck be discharged first and why?


1. (a) Construct a TPC curve from the following data:

Mean draft (m) 1 2 3 4 5

TPC (tonnes) 3.10 4.32 5.05 5.50 5.73

(b) From this curve find the TPC at drafts of 1.5m and 2.1m.

(c) If this ship floats at 2.2m mean draft and then discharges 45

tonnes of ballast, find the new mean draft.

State why no action must be taken related to ship stability without

written

2. Construct a TPC curve from the following data:

(a) From the following information construct a displacement curve:

Displacement (tonnes) 376 736 1352 2050 3140 4450

________________________________________________________



Mean draft (m) 1 2 3 4 5 6

(b) From this curve find the displacement at a draft of 2.3 m.

(c) If this ship floats at 2.3m mean draft and then loads 850 tonnes of

cargo and discharges 200 tonnes of cargo, find the new mean

draft.

(d) Find the approximate TPC at 2.5m mean draft.

Forms Coefficients

1. A ship is 150m long, has 20m beam, load draft 8m, light draft 3m.

The block coefficient at the load draft is 0.766, and at the light draft is

0.668. Find the ship's deadweight.

2. A ship 120m long x 15m beam has a block coefficient of 0.700 and is

floating at the load draft of 7m in fresh water. Find how much more

cargo can be loaded if the ship is to float at the same draft in salt

water.

3. A ship 100m long, 15m beam, and 12m deep, is floating on an even

keel at a draft at 6 m, block coefficient 0.8. The ship is floating in salt

water. Find the cargo to discharge so that the ship will float at the

same draft in fresh water.

Areas and Volumes of Ship’s Shapes

1. A ship's load water-plane is 60m long. The lengths of the half-

ordinates commencing from forward are as follows: 0.1, 3.5, 4.6, 5.1,

5.2, 5.1, 4.9, 4.3 and 0.1m respectively. Calculate the area of the

water-plane, the TPC in salt water, and the position of the centre of

flotation, from amidships.

2. The half-ordinates of a ship's water-plane, which is 60m long,

commencing from forward, are as follows: 0, 3.8, 4.3, 4.6, 4.7, 4.7,

4.5, 4.3, and 1m respectively: Find the area of the water-plane, the

TPC, the coefficient of fineness of the water-plane area, and the

position of the centre of flotation, from amid-ships.

3. The areas of a ship's water-planes commencing from the load water

and spaced at equidistant intervals down to the inner bottom, are:

2500, 2000, 1850, 1550, 1250, 900 and 800 sqm respectively. Below

the inner bottom is an appendage 1 metre deep which has a mean area

of 650 sq m. The load draft is 7 metres. Find the load displacement in

salt water, the Fresh Water Allowance, and the height of the centre of

buoyancy above the keel.


1. A box-shaped vessel 75m long, 12m beam and 7m deep, is floating

on an even keel at 6m draft. Calculate the KM.

2. Compare the initial metacentric heights of two barges, each 60 m.

long, 10m beam at the waterline, 6m deep, floating upright on an

even keel at 3m draft, and having KG = 3m. One barge is in the form

________________________________________________________



of a rectangular prism and the other is in the form of a triangular

prism, floating apex downwards.

3. Two box-shaped vessels are each 100m long, 4m deep, float at 3m

draft, and have KG = 2.5 m. Compare their initial Metacentric

Heights if one has 10m beam and the other has 12m beam.

4. Will a homogeneous log of square cross-section and relative density

0.7 have a positive initial Metacentric Height when floating in fresh

water with one side parallel to the waterline? Verify your answer by

means of a calculation.

Lists

1. A ship of 5000 tonnes displacement has KG 4.2 m, KM 4.5 m, and is

listed 5 degrees to port. Assuming that the KM remains constant, find

the final list if 80 tonnes of bunkers are loaded in No. 2 starboard tank

whose centre of gravity is 1 metre above the keel and 4 metres out

from the centre line.

2. A ship of 4515 tonnes displacement is upright and has KG 5.4 m, and

KM 5.8 m. It is required to list the ship 2 degrees to starboard and a

weight of 15 tonnes is to be shifted transversely for this purpose. Find

the distance through which it must be shifted.

3. A ship of 7800 tonnes displacement has a mean draft of 6.8m and is

to be loaded to a mean draft of 7 metres. GM = 0.7m TPC =20 tonnes.

The ship is at present listed 4 degrees to starboard. How much more

cargo can be shipped in the port and starboard tween deck, centres of

gravity 6m and 5m respectively from the centre line, for the ship to

complete loading and finish upright.


1. A ship of 10 000 tonnes displacement has GM 0.5 m. Calculate the

moment of statical stability when the ship is heeled 73/4

degrees.

2. When a ship of 12 000 tonnes displacement is heeled 51/4

degrees the

moment of statical stability is 300 tonnes.m KG 7.5 m. Find the

height of the metacentre above the keel.

3. Find the moment of statical stability when a ship of 10 450 tonnes

displacement is heeled 6 degrees if the GM is 0.5 m.

4. When a ship of 10 000 tonnes displacement is heeled 15 degrees, the

righting lever is 0.2 m, KM=6.8m. Find the KG and the moment of

statical stability.

5. A ship of 8000 tonnes displacement has KM = 7.3m and KG = 6.1 m.

A mass of 25 tonnes is moved transversely across the deck through a

distance of 15 m. Find the deflection of a plumb line which is 4m

long.

6. As a result of performing the inclining experiment it was found that a

ship had an initial metacentric height of 1m. A mass of 10 tonnes,

when shifted 12m transversely, had listed the ship 31/2

degrees and

________________________________________________________



produced a deflection of 0.25m in the plumb line. Find the ship's

displacement and the length of the plumb line.

7. A ship has KM=6.1m and displacement of 3150 tonnes. When a mass

of 15 tonnes, already on board, is moved horizontally across the deck

through a distance of 10m it causes 0.25m deflection in an 8m long

plumb line. Calculate the ship's KG.

8. Plot the curve of stability for M.V. `Tanker' when the displacement is

34 500 tonnes and KG = 9m. From this curve find the approximate

GM, the range of stability, the maximum GZ and the angle of heel at

which it occurs.

9. Plot the curve of statical stability for M.V. `Tanker' when the

displacement is 23 400 tonnes and KG = 9.4 m. From this curve find

the approximate GM, the maximum moment of statical stability and

the angle of heel at which it occurs. Find also the range of stability.

10. The displacement of M.V. `Tanker' is 24700 tonnes and KG = 10 m.

Construct a curve of statical stability and state what information may

be derived from it. Find also the moments of statical stability at 10

degrees and 40 degrees heel.

11. Construct the curve of statical stability for M.V. `Cargo-Carrier' when

the displacement is 35 000 tonnes and KG is 8 metres. From this

curve find;

(a) the range of stability,

(b) the angle of vanishing stability and,

(c) the maximum GZ and the heel at which it occurs.

Construct the curve of statical stability for M.V. `Cargo-Carrier'

Trim

1. A ship of 8500 tonnes displacement has TPC 10 tonnes, MCT 1 cm =

100 tonnes m and the centre of flotation is amidships. She is

completing loading under coal tips. Nos. 2 and 3 holds are full, but

space is available in No. 1 hold (centre of gravity 50m forward of

amidships), and in No. 4 hold (centre of gravity 45m aft of

amidships). The present drafts are 6.5m F and 7m A, and the load

draft is 7.1m. Find how much cargo is to be loaded in each of the end

holds so as to put the ship down to the load draft and complete

loading on an even keel.

2. An oil tanker 150m long, displacement 12 500 tonnes, MCT 1 cm 200

tonnes m, leaves port with drafts 7.2m F and 7.4m A. There is 550

tonnes of fuel oil in the forward deep tank (centre of gravity 70m

forward of the centre of flotation) and 600 tonnes in the after deep

tank (centre of gravity 60m aft of centre of flotation). The centre of

flotation is 1m aft of amidships. During the sea passage 450 tonnes of

oil is consumed from aft. Find how much oil must be transferred from

the forward tank to the after tank if the ship is to arrive on an even

keel.

________________________________________________________



3. A ship 100m long, and with a displacement of 2200 tonnes, has

longitudinal metacentric height 150 m. The present drafts are 5.2m F

and 5.3m A. Centre of flotation is 3m aft of amidships. Find the new

drafts if a weight of 5 tonnes already on board is shifted aft through a

distance of 60 metres.

Dry-Docking and Grounding

1. A ship being drydocked has a displacement of 1500 tonnes. TPC = 5

tonnes, KM = 3.5 m, GM = 0.5m, and has taken the blocks fore and

aft at 3m draft. Find the GM when the water level has fallen another

0.6 m.

2. A ship of 4200 tonnes displacement has GM 0.75m and presents

drafts 2.7m F and 3.7m A. She is to enter a drydock. MCTC = 120

tonnes m. The after keel block is 60m aft of the centre of flotation. At

3.2m mean draft KM = 8m. Find the GM on taking the blocks

forward and aft.

3. A box-shaped vessel 150m long, 10m beam, and 5m deep, has a mean

draft in salt water of 3m and is trimmed 1m by the stern, KG = 3.5 m.

State whether it is safe to drydock this vessel in this condition or not,

and give reasons for your answer.

Damage Control

1. (a) Define permeability, `'.

(b) A box-shaped vessel 100m long, 15m beam floating in salt water,

at a mean draft of 5m, has an amidships compartment 10m long

which is loaded with a general cargo. Find the new mean draft if this

compartment is bilged, assuming the permeability to be 25 per cent.

2. A box-shaped vessel 30m long, 6m beam, 5m deep, has a mean draft

of 2.5m. An amidships compartment 8m long is filled with coal

stowing at 1.2 cu.m per tonne. 1 cu.m of solid coal weighs 1.2 tonnes.

Find the increase in the draft if the compartment is holed below the

waterline.

3. A box-shaped vessel 75mx12m is floating upright in salt water on an

even keel at 2.5m draft F and A. The forepeak tank which is 6m long

is empty. Find the final drafts if the vessel is now holed forward of

the collision bulkhead.

4. A box-shaped vessel 64mx10mx6m floats in salt water on an even

keel at 5m draft. A forward compartment 6 metres long and 10 metres

wide, extend from the outer bottom to a height of 3.5m, and is full of

cargo of permeability 25 per cent. Find the new drafts if this

compartment is now bilged.

Rudders

1. A ship, whose maximum speed is 18 knots, has a rudder of area 25

m2. The distance from the centre of stock to the centre of effort of the

________________________________________________________



rudder is 1.2 m and the maximum rudder angle 350. If the maximum

allowable stress in the stock is 85 MN/m2, calculate the diameter of

stock.

2. A ship 150 m long and 8.5 m draught has a rudder whose area is one

sixtieth of the middle line plane and diameter of stock 320 mm.

Calculate the maximum speed at which the vessel may travel if the

maximum allowable stress is 70 MN/m2, the centre of stock 0.9 m

from the centre of effort and the maximum rudder angle 350.


1. A ship has a wetted surface area of 3200m2. Calculate the power

required to overcome frictional resistance at 17 knots if n=1.825 and f

= 0.424.

2. A plate towed edgewise in sea water has a resistance of 13N/m2 at

3m/s. A ship travels at 15 knots and has a wetted surface area of

3800m2. If the frictional resistance varies as speed1.97

, calculate the

power required to overcome frictional resistance.

3. The residuary resistance of one-twentieth scale model of a ship in sea

water is 36N when towed at 3 knots. Calculate the residuary

resistance of the ship at its corresponding speed and the power

required to overcome residuary resistance at this speed.

4. A ship’s speed was 18 knots. A reduction of 3.5 knots gave a saving

in fuel consumption of 22 tonnes per day. Calculate the consumption

per day at 18 knots.

5. The daily fuel consumption of a ship at 17 knots is 42 tonnes.

Calculate the speed of the ship if the consumption is reduced to 28

tonnes per day, and the specific consumption at the reduced speed is

18% more than at 17 knots.


1. A ship travels at 14 knots when the propeller, 5 m pitch, turns at 105

rev/ min. If the wake fraction is 0.35, calculate the apparent and real

slip.

2. A ship of 15,000 tonnes displacement has an Admiralty Coefficient,

based on shaft power of 420. The mechanical efficiency of the

machinery is 83%, shaft losses 6%, propeller efficiency 65% and

QPC 0.71. At a particular speed the thrust power is 2550 kW.

Calculate; indicated power, effective power, and ship speed.

Hydrostatics

1. A piece of aluminum has a mass of 300 g and its volume is 42 cm3,

calculate;

a. its density in kg/ m3

b. its relative density

c. its mass of 100 cm3 of aluminum

________________________________________________________



2. A vertical bulkhead 9 m wide and 8 m deep has sea water on one side

only to a depth of 6 m. Calculate the pressure in kN/ m2 at the bottom

of the bulkhead and the load on the bulkhead.

3. A triangular bulkhead is 7 m wide at the top and has a vertical depth

of 8 m. Calculate the load on the bulkhead and the position of the

centre pressure if the bulkhead is flooded with sea water on only one

side:

a. to the top edge

b. with 4 m head to the top edge

Additional Questions

Ship Construction

1. State the reasons for fitting bulbous bows

2. Explain the effects and direction of wind speed on ship speed.

3. Emergency action following hull damage

4. Explain the planning necessary in preparation for emergency action.

5. Describe the ship’s systems and equipment which should be included

in preparations for emergencies.

6. Describe the procedure to follow if a ship’s hull is holed.

7. Describe how portable pumps are used.

8. Explain the limiting factors on temporary repairs.

9. Discuss possible repairs to hull damage.

10. Describe the motion if unrestricted rolling occurs in still water.

11. Explain that large rolling angles will occurs if a wave frequency

synchronizes with the natural rolling period of the ship.

12. Describe the passive and the active methods used to reduce rolling.

13. Explain what is meant by synchronous or resonant vibration and its

significance.

14. Describe local vibration and how to overcome it.

15. Describe the normal sources of vibration.

16. Describe the statical forces acting in the structure.

17. Describe the dynamical forces acting on the structure.

18. Describe the conditions of hogging and sagging

19. Describe the different types of keel construction in general use

20. Explain the purpose of a duct keel

21. Explain that the access to duct keels should be closed and watertight

unless in use

22. Sketch the construction of both transversely framed and

longitudinally framed double-bottom tanks in container ships, oil

tankers, under machinery and in the pounding region.

23. Explain how continuity of strength is maintained in the vicinity of

openings in the shell.

24. Describe the different framing systems in common use.

25. Explain the purpose of a bilge keel and how it is attached to the hull.

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26. Describe how deck plating is supported.

27. Describe the effect of discontinuities in the main structure.

28. Describe the effect of discontinuities in the main structure.

29. Summarize the requirements concerned with openings in the shell,

with emphasis on suction and discharge fittings.

30. Describe the purpose of the different types of bulkhead.

31. Explain the minimum number and location of watertight bulkheads.

32. Explain that additional bulkheads are necessary in cargo ships

according to the ship’s length.

33. Describe the construction of a watertight bulkhead, including its

attachment to the rest of the structure.

34. Describe how bulkheads are tested.

35. Explain how access is provided through bulkheads and how water

tightness is maintained.

36. Explain how the strength of bulkheads is maintained in way of

openings.

37. Describe examples of non-watertight bulkheads.

38. Describe the routine procedures for the use and testing of watertight

doors.

39. Describe the construction of a class 1, 2 & 3 watertight doors and

gastight door.

40. Describe how watertight doors are operated.

41. Explain what is meant by panting and pounding or slamming.

42. Sketch and describe the construction of a bow and how the structure

is strengthened to withstand pounding and panting.

43. Sketch and describe typical principal features of a bulbous bow and

the anchor and cable arrangements.

44. Sketch & describe the construction of a typical ship’s stern.

45. Describe typical strengthening in way of deck, propulsion machinery

and pumps.

46. Describe an inlet box suitable for ship side valves.

47. Explain what is meant by ‘natural gas’ and ‘petroleum gas’.

48. Describe the condition in which natural gas is carried, stating its

temperature and pressure.

49. Describe the main problems of carrying liquefied natural gas.

50. Describe briefly the tank systems in liquefied natural gas carriers.

51. Explain how the boil-off from liquefied natural gas is handled

52. Describe briefly the three basic types of liquefied petroleum gas

carrier, giving the approximate cargo temperature and pressures of

each.

53. Explain why a secondary barrier is necessary.

54. Explain why the cargo pumping system must be entirely separate

from other systems.

55. Explain, in principle, how leakage is dealt with.

56. Explain why stabilizers are not finding a wider application.

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57. Write short notes on various types of stabilizer systems fitted on

ships.

58. Differentiate a destructive test and a non-destructive test with respect

to weldments.

59. Explain with a sketch the operation of an active tank type of stabiliser

60. Sketch and explain the operation of a retractable type of fin stabiliser.

61. Discuss the meaning of local vibration

62. Discuss the meaning of resonant vibration.

63. Explain with sketches the generation of lift and drag forces on a

rudder

64. Discuss the construction of double plate rudder and compare its

advantages over a single plate design.

65. Explain with a sketch a kort nozzle propeller

66. Discuss the meaning of propeller singing and explain how this

phenomenon is overcome.

67. Explain the types of prime movers used for bow thrusters. What are

the advantages of one over the other.

Acknowledgement

International Maritime Organisation (IMO), IMO Model Course (3.09),

(7.02), (7.04) (2001), DNV Seaskills Learning Guide

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