Lg Ecsu Nasc 170413
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Transcript of Lg Ecsu Nasc 170413
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ECSU(M&S)/ Control Operation of Ship NASC/Vers.No.1/April 2013 1
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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
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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.
Resistance, Powering and Fuel Consumption
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.
Transverse Statical Stability
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
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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
Movement of the Centre of Gravity
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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Transverse Statical Stability
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.
Correcting an Angle of Loll
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.
TPC and Displacement Curves
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.
KB, BM and Metacentric Diagrams
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.
Moment of Statical Stability
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.
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4. Explain, in principle, how the torque on the rudder stock is
established.
5. Explain the effect on the torque when running astern.
Resistance, Powering and Fuel Consumption
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.
Propulsion and Propellers
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.
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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
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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.
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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
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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
Movement of the Centre of Gravity
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.
Transverse Statical Stability
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
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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', `initial metacentre' and `initial
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 `angle 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.
Correcting an Angle of Loll
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?
TPC and Displacement Curves
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
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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.
KB, BM and Metacentric Diagrams
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
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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.
Moment of Statical Stability
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
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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.
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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
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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.
Resistance, Powering and Fuel Consumption
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.
Propulsion and Propellers
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
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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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