DieselShip's Online Content Library

Q1. Describe with the aid of diagrammatic sketches the following systems used for transporting liquefied gas in bulk:

a) Free-standing prismatic tanks

b) Membrane tanks.

c) Free-standing spherical tanks.

Q1. Common rail fuel injection systems have made a come back in marine diesel engines, the older mechanically controlled system have been replaced by electronic/hydraulic controlled system. Describe, with a line diagram any one type of a modern CR system, mentioning the engine type.

b) Compare the advantages and disadvantages of the common rail fuel injection system with the jerk type of injection system. Give examples of their use in modern diesel engines.

Q1. With reference to automatic sprinkler system for firefighting purposes:

a) Explain, with the aid of a heat release versus time diagram, the difference between fire control and fire suppression

b) State the limitations of using glass bulb to activate sprinkler heads and suggest, with reasons, an alternative mechanism

c) The safety devices incorporated in the system

d) The parameters governing the volume of the pressure tank

Q1. a) What do you understand by the terms Convention, Protocol, Amendments? State in which order these will be adopted by the IMO? (10)

b) What procedure is nowadays followed for putting the amendments into effect? (10)

Q1. A. Sketch a main engine shaft driven generator arrangement with an electronic system for frequency correction.  B. Describe the operation of the generator arrangement sketched in (A).

Q7. What is Rocking test of Deck Crane? Explain the procedure of rocking test. Tabulate and indicate fault finding procedure. What is the action taken if deviation is out of limit?

Q2. With reference to MLC answer the following;

a) Briefly discuss DMLC Part I and Part II covering the welfare points for seafarers (10)

b) Briefly discuss the grievance redressal mechanism for seafarers of Indian flagged vessel (10)

Q2. With reference to testing High Voltage equipment:

(a) Explain why earthing down is considered essential.

(b) Briefly describe the procedures of earthing down

(c) describe how an insulation resistance test is carried out on High Voltage equipment, making reference to personnel safety;

(d) Describe, with the aid of a sketch, a method to detect earth leakage in EACH of the following systems:

(i) Earthed

(ii) Insulated

Q2. a) Define creep and specify the conditions under which it occurs?

b) Discuss three metallurgical processing techniques that are employed to enhance the creep resistance of metal alloys

Q3. A. Explain what is meant by permissible length of compartments in passenger ships;

B. Describe how the position of bulkheads is determined.

C. Describe briefly the significance of the factor of subdivision.

Q1. Explain why auxiliary engine bottom-end bolts are prone to failure, even under normal running conditions. Identify those features, incorporated into the design of bottom-end bolts, to inhibit failure. Explain how this tendency is either aggravated or inhibited during maintenance and what checks are to be carried out.

Q2. A. Explain the term Variable Injection Timing (VIT) when applied to fuel pumps and state why a change in timing of fuel injection may be required.;

B. Describe, with the aid of sketches a VIT fuel pump and explain how the change in timing is achieved whilst the pump is in operation

C. Explain how it may be determined that individual fuel pumps are injecting the correct quantity of fuel with the correct timing at a particular pump setting.

Q3. What is "virtual tappet" in the hydraulically actuated air spring return exhaust valves, and how is it set. Explain why the damage occurs to the seats of the exhaust valves due to furrowing and cutting. How an incident of "valve drop" leading to extensive damage to running gear can occur.

Q3. With reference to main Thrust bearing of the pivoting pad type, explain with sketches where necessary –

a) The principle of operation of the bearing

b) The critical clearances and why they are critical?

c) How these clearances are adjusted

d) Why such bearings sometime overheat although the clearances are adequate?

e) How is the lubrication film between faces of collar and thrust pad maintained?

Q3. a) Explain why pilot injection is required for a Dual fuel engine when burning natural gas.

b) Describe, with the aid of a sketch, the arrangements for a dual fuel engine which is capable of burning natural gas on;

    a) The otto cycle

    b) The Diesel cycle.

Q4. With reference to Underwater Inspection in lieu of Dry  docking (UWILD)

A. Explain in detail, how an underwater survey is carried out;

B. State the requirements to be fulfilled before an underwater survey is acceptable to the survey authority.

C. Construct a list of the items in order of importance that the underwater survey authority should include.

Q6.  With regard to ballast water Management Convention, Explain following:

(a) Ballast water exchange standard     (b) Ballast water Performance standard

(c) Treatment methods for ballast water

(d) Approval methods for treatment system using active and non-active substances

(e) What are the marine pollution problems related to port development such as ballast water, dredging and spills from ships.

Q9. Explain What is meant by, and the significance of, four of the following terms.

I. Voltage Stabilization,

II. Filter choke;

III. Impedance,

IV. Rectification,

V. Grid bias voltage.

Q4. Explain the meaning of ‘P’ and ‘N’ types semi-conductor materials and give a brief description of the mechanism by which current passes through them.

Q4. Many modern turbochargers use sleeve type bearings for rotor support.

A. Explain the reasons for their preference over the rolling contact bearings;

B. With a sketch describe the lubricating system provided for this type;

C. In a turbocharger with integral type of bearings, describe the procedure for renewing the bearings.

Q4. a) Describe, with the aid of a sketch, an external system for reducing engine NOx emission, explaining the chemistry of the process

b) Explain why Urea is used in the selective catalytic reduction process instead of ammonia.

(c) Explain why the exhaust gas quality must be monitored before and after the selective catalytic reduction unit, stating how such monitoring influences operation of the SCR unit.

Q4. (a) Describe, with the aid of a sketch, an open loop system for reducing SOx emissions from engine exhaust gas, explaining how the system operates whilst the vessel is in open waters.

(b) Describe, with the aid of a sketch, a closed loop scrubber system for removing SOx from engine exhaust gas, explaining the operation of this unit and stating when it would be used.

Q6. With respect to MARPOL 73/78, Annex - II, Noxious liquid chemicals are divided into categories; A. State the number of categories, and what does each category signify. B. State the requirement of Procedures and Arrangements Manual, and what information is available.

Q2. A. Describe the double bottom and framing arrangement used in the machinery space to cope up with the concentrated loads and vibration, together with shaft and thrust block support.

B. Give reasons for the choice of thrust block position.

Q6. Hydrogen damage is a general term used for mechanical damage of metal caused by the

presence of hydrogen, briefly discuss the different types of hydrogen damage and how these damages can be prevented?

a) Hydrogen blistering (4)

b) Hydrogen embrittlement (4)

c) Decarburization (4)

d) Hydrogen attack (4)

1. Q5. a) With reference to a vapour compression refrigeration plant, explain why each of the following conditions are desirable;

(i) Superheating at the compressor suction

(ii) Undercooling at the condenser outlet

(b) Describe, with the air of a pressure-enthalpy diagram, how the evaporator cooling load is affected by the conditions stated in Q5 (a)

Q5. a) Describe, with the aid of a sketch, the arrangement of the Gas and liquid fuel systems at the cylinder of a dual fuel 4-stroke engine, stating the input and output signals at the controller.

(b) Describe the arrangement of the gas fuel piping system used for a 4 stroke dual fuel engine with safety features incorporated.

Q2. With reference to Roll-on Roll-off ferries –

A. Describe the problem of free surface effect;

B. Explain how it is intended that water should be cleared from car or cargo decks;

C. Describe possible methods for improving the stability and survivability of these vessels.

Q3. With reference to SOLAS Ch-XII (Additional safety measures for bulk carriers);

A. Damage stability requirements for bulk carriers;

B.  Structural requirements for bulk carriers;

C. Water ingress alarms.

Q5. With reference to electronic control systems A. Draw a simple block diagram for temperature control B. Describe each component shown in the diagram in (a).

Q6.a) Define centre of buoyancy and show with the aid of sketches how a vessel which is Stable will return to the upright after being heeled by an external force (6)

b. An oil tanker of 17000 tonne displacement has its centre of gravity 1 m aft of midships and has 250 tonne of oil fuel in its forward deep tank 75 m from midships. This fuel is transferred to the after oil fuel bunker whose centre is 50 m from midships. 200 tonne of fuel from the after bunker is now burned. (10)

Calculate the new position of the centre of gravity:

(a) after the oil has been transferred

(b) after the oil has been used.

Q6. During loading of a petroleum tanker, the incoming cargo forces out from the tank its previous atmospheric contents (air-vapour-inert gas)

a) Explain: (10)

(i) The dangers of venting during the loading via open tank hatches

(ii) Why the pressure / vacuum valve is not used venting

b) Sketch and describe a patent high velocity vent and state why such device is used (10)

Q6. a) Derive the expression for current and voltage relations between line and phase values in the star and delta cases. Draw vector diagram.

b) Three impedances Z=5+j4 are connected in the form of a delta to the three loads of a balanced 3-phase circuit. The line voltage is 120 Volts.

Find (a) The phase current, (b) Power factor, (c) The volt-ampere in the circuit.

Q6. With reference to main shaft bearings that are excessively loaded or very lightly loaded state for each condition what are the;

a) Indications of the fault,

b) Effects on adjacent bearings

c) Remedial steps.

Explain why load distribution on main shaft bearings changes in service.

Q6. Draw a line diagram of a Boiler combustion control system labelling the principal items, explain how the system functions and in particular how feed water supply, fuel supply and air/fuel ratio are regulated to match steam pressure and flow variation.

Explain how these controls can be tested for alarm conditions without upsetting the balance of the system.

Q6. With reference to keyless propellers explain:

a) Why keys and keyways have been eliminated

b) How angular slip is avoided

c) Why mounting upon and removal of a propeller shaft requires a different technique than that employed for propeller with keys.

d) State with reasons why use of wedges and jacks are not advisable when removing the propeller from its shaft

7.a) Explain the term Angle of loll and state the dangers it poses to a vessel. What action to be taken to correct angle of loll. (6)

b. A ship of 22000 tonne displacement is 160 m long and MCTI cm 280tonne m, waterplane area 3060 m2 centre of buoyancy 1 m aft of midships and centre of flotation 4 m aft of midships. It floats in water of 1.007 t/ m3 at draughts of 8.15 m forward and 8.75 m aft.

Calculate the new draughts if the vessel moves into sea water of 1.026 t/ m2

Calculate the metacentric height of the vessel. (10)

Q7. (a) Specify with reasons those parts requiring particularly close scrutiny during internal and external examinations of independently fired auxiliary boilers.

(b) With reference to these examinations distinguish between metal fatigue due to caustic embrittlement, corrosion fatigue, overheating (plastic flow) and direct overpressure.

Q7. What is meant by ‘Power balancing’ with respect to reciprocating engines? Why is balance desirable and how is it obtained in the case of a large marine engine? What difficulties may be experienced in balancing an engine running at about 500 R.P.M. and how can these difficulties be overcome?

Q7. With reference to fire smothering agents explain as to why:

A. Effectiveness of foam is directly related to its degree of effervescence and surface tension? (7)

B. Low expansion foam is best suited for use against localized fire, whilst high expansion foam is most effective in major conflagrations?        (7)

C. In the absence of foam appliances, water jets can be effectively used against oil fires? (5)

D. Explain how a mixture of foam making compound and sea water are converted into foam (5)

Q9. A. Discuss different methods of speed control of a d.c. series motor by adjusting field ampere turns.

B. A 230 V, d.c. shunt motor runs at 1000 r.p.m and takes 5 amperes. The armature resistance of the motor is 0.025𝛀 and shunt field resistance is 230𝛀. Calculate the drop in speed when the motor is loaded and takes the line current of 41 amperes. Neglect armature reaction.

Q9. With reference to main boiler super heater arrangements:

A. Compare the advantages and disadvantages of contra flow with parallel flow design.

B. Describe how the element tube banks are supported yet allow for expansion.

C. Describe how boiler carryover affects super heater effectiveness and condition.

Q8. (a) List the variables which affect the force on Rudder (6)

b) A ship of 12000 tonne displacement has a rudder 15 m2 in area, whose centre is 5 m below the waterline. The metacentric height of the ship is 0.3 m and the centre of buoyancy is 3.3 m below the waterline. When travelling at 20 knots the rudder is turned through 30 degree. Find the initial angle of heel if the force Fr perpendicular to the plane of the rudder is given by:

Fr=577Av2 Sin N

Allow 20% for the race effect. (10)

Q8. a) Discuss the Merits and demerits of a condition monitoring system compared to other maintenance regimes.

b) Describe how the data is gathered, stored and evaluated on a computer-based vibration analysis system

Q8. With reference to Main engine crankshafts:

a) Explain the term axial vibration

b) Describe, with the aid of a sketch, how axial vibration may be minimised

c) State with reasons which bearing would be most at risk due to the effects of axial vibration

d) Describe how damage to the bearing stated in part (c) may be repaired.

Q8. In a Rotary vane steering gear, briefly state.

a) How are the fixed and moving vanes attached to cylinder and rotor respectively.

b) How many sets of vanes are provided? What is the limitation factor to number of vanes.

c) How is strength imparted to moving vanes to enable them to act as rudder stops?

d) How is rudder uplift accommodated?

Q9. A. What are the factors which determine the synchronous speed of a motor? B. The star-connected rotor of an induction motor has a stand-still reactance of 4.5 ohms/phase and a resistance of 0.5 /phase. The motor has an induced emf of 50 V between the slip-rings at stand-still on open circuit when connected to its normal supply voltage. Find the current in each phase and the power factor at start when the slip-ring is short-circuited.

Q7. Which legislation is framed at preventing the emission of black smoke, sets the limits on the length of time of such emission?

A. Discuss the reasons for setting time limits rather than imposing a complete ban on emission

B. State why different times are quoted, giving examples.

C. State the likely constituents of black smoke from the combustion of residual fuel in a boiler.

D. List the contaminants likely to be found in the clear exhaust from a diesel driven alternate burning gas.

Q9. a) Explain the concept of Dynamical stability. (6)

b) The wetted surface area of a container ship is 5946 m2, when travelling at its service speed, the effective power required is 11250 KW with frictional resistance 74% of the total resistance and specific fud consumption of 0.22 Kg/kW h. To conserve fuel, the ship speed is reduced by 10%, the daily fuel consumption is then found to be 83.0 tonne

Frictional coefficient in sea water is 1.432.

Speed in m/s with index (n) 1.825.

Propulsive coefficient may be. assumed constant at 0.6.

Determine

the service speed of the ship

the percentage increase in specific: fuel consumption when running at reduced speed. (10)

Q9. Write short notes on;

a) Harmonization of survey and certification (4)

b) Enhanced survey programme (ESP) surveys for bulk carriers and oil tankers (4)

c) Condition monitoring of tail shaft propeller shaft (4)

d) Condition assessment program (4)

e) Condition assessment scheme (4)

Q9. a) List the design problems associated with safety valves for high-pressure boilers.

b) State the factors that determine

(i) The relationship between the working pressure of the boiler and the setting pressure of the safety valve

(ii) The blow down setting of a safety valve

c) State what determines the settings of

(i) The super heater safety valve

(ii) The drum safety valve.

Q9. With reference to tubular heat exchangers explain:

a) How differential movement tubes and body is accommodated when the tube plates are rigidly located in the body,

b) How and why turbulence is imparted to fluid flow through the tubes,

c) Why it has become possible to discard sacrificial anodes in sea water coolers,

d) What is meant by the term ‘guided flow’, with particular reference to oil heaters.

Q9. Misalignment of the Main shafting between engine and propeller causes bearing overloads and shaft stress.

a) State the difficulties associated with checking the shaft alignment and the reasons why results are unreliable due to external factors.

b) State the reasons for misalignment

c) Explain with a simple sketch how a bearing load is assessed.

d) Explain how uneven loading could be rectified

e) Why wear down in main bearings is critical to the condition of the condition of the crankshaft and propeller system.

Q8. A. Explain the purpose of interlopes and state their magnetic polarity relative to the main poles of both generators and motors.

A 200V, long-shunt compound-wound generator has a full-load output of 20kW. The various resistances are as follows; armature (including brush contact) 0.15 ohm, series field 0.025 ohm, interpole field 0.028 ohm, shunt field (including the field-regulator resistance) 115 ohm. The iron losses at full load are 780W, and the friction and wind age losses 590W. Calculate the efficiency at full load.

10.A box-shaped barge of uniform construction is 80 m long, 12 m beam and has a light displacement of 888 tonne. The barge is loaded to a draught of 7 m in sea water of density 1025 kg/ m? with cargo evenly distributed. over two end compartment of equal length. The empty midship compartment extending to the full width and depth of the barge is bilged and the draught increases to 10m.

Determine:

(a) the length of the midship compartment.

(b) the longitudinal still water bending moment at midships:

(i) in the loaded intact condition

(ii) in the new bilged condition

Q10. What is direct-connected alternator? How is a direct-connected exciter arranged in an alternator?  Sketch a graph of starting current, and torque against the speed of rotation for a single cage motor. A 440V shunt motor takes an armature current of 30A at 700 rev/min. The armature resistance is 0.7 ohm. If the flux is suddenly reduced 20 per cent, to what value will the armature current rise momentarily? Assuming unchanged resisting torque to motion, what will be the new steady values of speed and armature current? Sketch graphs showing armature current and speed as functions of time during the transition from initial to final, steady-state conditions.