DieselShip's Online Content Library

Q1. a) What is the meaning of excitation in an alternator? (6)

b) Explain a brushless alternator with an insight on how the excitation is achieved in these alternators. (10)

Q1. (a) Sketch and describe the Starting air system of main engine. (8)

(b) What are the safety interlocks provided in compressed air Starting system of Main Engine? (8)

Q1. Oil traces have been found in the condensate tank of an auxiliary boiler:

(a) Describe the procedure to trace the source of contamination (8)

(b) List the contamination with reasons for its occurrence and the precaution to be taken to ensure safety of the boiler (8)

Q1. For a ship the center of buoyancy and the metacenter are in the line of action of the buoyant force.

(a) Only when there is positive stability

(b) Only when there is negative stability

(c) Only when there is neutral stability

(d) At all times

Justify your answer.

Q2. (a) What are the short-term measures devised by IMO for controlling the emission of Green House gases (5)

(b) State the measures and how they will take effect. What size of ships are these rules applicable to? (5)

(c) What documents will be required to be carried on board under the new regulations? (5)

(d) What is SEEMP Part III? State its contents (5)

Q1. (i) Discuss the use of non-metals onboard ships & name some of the common nonmetals used. (4)

(ii) What are their areas of application on ships? (4)

(iii) Name the advantages & also the limitations in using non-ferrous materials (8)

Q2. a) What are the differences between synchronous and induction motor? (6)

b) What do you understand by the term ‘slip’? (4)

c) How do you check continuity of a circuit? Explain the process in brief. (6)

Q2. (a) Draw sectional diagram of main engine piston showing each part. Show cooling passages for oil cooled piston (12)

(b) Name the different materials used for the various components of the piston as indicated to the answer above. (4)

Q2. (a) Describe how cylinder liners are checked for wear (5)

(b) Explain how these measurements are recorded (5)

(c) Explain why allowance for wear is limited and what extent of the wear governs liner replacement (6)

Q2. Explain the meaning and purpose of EACH of the following terms:

(a) Duct keel (4)

(b) Margin line (4)

(c) Sheer (4)

(d) Round of Bilge (4)

Q5. (a) Name and describe in detail any three mandatory IMO Codes. Explain their significant features. (15)

(b) What do you understand by the term 'Protocol to a convention' Give examples. (5)

Q8. (a) Sketch a two-ram type hydraulic steering gear with a single Electro-hydraulic pumping unit. Show the hunting gear arrangement and indicate valve positions (8)

(b) State the purpose of, and describe the operation of:

(i) Hydraulic shock/buffer valves (3)

(ii) Oil replenishing tank (2)

(iii) Hunting gear (3)

Q3. a) Describe an alkaline battery cell, listing the materials used in its manufacture. (6)

b) With reference to alkaline batteries used on ships, state each of the following: (10)

i) Significance of the relative density reading of the electrolyte.

ii) When the electrolyte would normally be renewed.

iii) Reasons why the voltage reading of this type of battery is not necessarily indicative of its condition.

iv) The normal temperature range and safe temperature limit of battery.

v) Effects of high and low temperature.

Q3. a) Explain, why is it important to measure bearing clearance in a diesel engine. (4)

b) What is Bridge gauge? How is the Bridge gauge used? Explain with a diagram. (6)

c) What are other recommended methods for checking bearing clearances. (6)

Q3. State some built in measures by which the steering gear mechanism can be kept operational, in the event of breakages, pipe failures, motor burn out etc. (16)

Q4. With reference to hull protection against corrosion describe how EACH of the following operate:

a) Sacrificial anodes (8)

b) Impressed current system (8)

Q3. Explain how each of the following conditions contribute to the satisfactory performance of oil centrifuges.

(a) Correct bowl speed (4)

(b) Cleanliness of bowl (4)

(c) Low rate of feed to bowl (4)

(d) Contaminated oil allowed to stand for an appreciable time prior to centrifuging. (4)

Q4. Describe with the aid of a diagram the operation of the following components of electrical equipment and explain the purpose of each. (16)

a) Under voltage protection.

b) Miniature circuit breakers.

c) Reverse power tripping.

Q4. With reference to bilge keels:

(a) Describe how the design and method of attachment reduces the possibility of damage to the shell plate. (8)

(b) State what testing must be carried out. (4)

(c) Explain why the bilge keels do not extend the full length of the vessel. (4)

Q4. Describe following terms with respect to Diesel Engine with suitable diagram.

a) Piston Stroke (4)

b) Swept Volume (4)

c) Clearance volume (4)

d) Compression ratio. (4)

Q4. Where a waste heat boiler is subject to persistent leakage at the tube / tube plate connection, suggest with sketches, methods of effecting a permanent repair. (16)

Q4) Describe with the aid of suitable graph, the discharge characteristics of a centrifugal pump. Explain why it does not require a relief valve (16)

Q5. With respect to personnel carrying out inspection and maintenance involving entry to boilers and other confined spaces.

a) State the precautions needed for the operation of portable electrical tools and lighting, with respect to safety. (10)

b) Outline the routine checks carried out on the equipments. (6)

Q5. With reference to large bulk carriers:

(a) Sketch a cross section of a bulk carrier through the mid-ship. (8)

(b) Explain the design features that have evolved to minimise the possibility of failure. (8)

Q5. (a) What is a Exhaust Gas Economizer? Draw diagrammatic Sketch of Exhaust gas Economizer (EGE) naming each component (8)

(b) How is steam Generation controlled in Exhaust Gas Economizers? (4)

(c) Briefly describe procedure to maintain efficiency of such an E.G.E. (4)

Q5. (a) What are the routines carried out on a lifeboat winch (6)

(b) What maintenance do the hand brake and Centrifugal brakes require (5)

(c) At what lowering velocity does the centrifugal brake operate (5)

Q5) With regard to a reciprocating refrigerator compressor.

(a) Sketch the mechanical shaft seal showing its component parts and how it is lubricated (8)

(b) Describe the sealing arrangement stating the materials used for the component parts (4)

(c) State the effect on the environment of the release of refrigerants into the atmosphere (4)

Q6. If an auxiliary diesel generator over speeds while off load, explain:

(a) How can the engine be stopped? (6)

(b) What are the probable reasons for the failure? (4)

(c) Give details of the checks that are required to be made after the engine has been stopped, with regard to

(i) Mechanical checks and

(ii) Electrical checks (6)

Q6. Give reasons and remedies for the following faults in air compressors.

(a) Excessively hot discharge pipe (5)

(b) Intermediate stage relief valve lifting (5)

(c) Noticeable reduction in free air delivery (6)

Q6) (a) Sketch an auxiliary boiler ‘blow down’ valve. Explain how it differs from its shipside counterpart (10)

(b) Describe the sequence of ‘blow down’ procedure (6)

Q6. (a) Define angle of loll (6)

(b) A box barge 60 m long and 10m wide floats at an even keel draught of 4 m. It has a compartment amidships 12 m long. Calculate the new draught if this compartment is laid open to the sea when: (10)

(i) µ is 100%

(ii) µ is 85%

(iii) µ is 60%

Q6. a) Discuss the open circuit and short circuit test performed for transformer. (6)

b) The primary and secondary windings of a 30 KVA, 6000/230V, 1-phase transformer have resistance of 10 Ω and 0.016 Ω respectively. The reactance of the transformer referred to the primary is 34 Ω. Calculate the primary voltage required to circulate full load current when the secondary is short circuited. What is the power factor on the short circuit? (10)

Q7. a) Explain what do you understand by the term ‘transducer’? (6)

b) A coil of resistance 10 ohms and inductance 100mH is connected in series with two parallel capacitors each of value 100 mF across a 250 V, 50Hz supply. determine (10)

i) The circuit current

ii) The total power factor

iii) The power taken from the supply.

Q7. (a) What do you understand by ‘coffin plate’?

(b) A ship displacing 10000 tonne and travelling at 16 knots has a fuel consumption of 41 tonne per day. Calculate the consumption per day if the displacement is increased to 13750 tonne and the speed is increased to 17 knots. Within this speed range, fuel consumption per day varies as (speed)^3/8 (10)

Q7. (a) In a 4-Stroke engine, describe each of the different strokes of the cycle. (6)

(b) Draw 4-Stroke timing diagram describing the complete cycle.

Explain how each stroke is completed with action of crank travel and the inlet-exhaust valves. (10)

Q7. With reference to auxiliary boiler safety valves state with reasons:

(a) What clearances need checking when lapping valves to seats (5)

(b) Why the drain must be clear (5)

(c) Why opening gear should be kept in good working order at all times (6)

Q9. (a) State with reasons the essential requirements for unattended machinery spaces (8)

(b) With reference to a periodically unattended machinery space of a dry cargo vessel discuss the requirements for:

(i) Protection against flooding (6)

(ii) Control of propulsion machinery from the navigating bridge (6)

Q7) Submit a report to the Chief Engineer stating how the freshwater generator output on board you ship was increased to near optimal values. The report should specifically mention the adjustments, corrections and improvements executed (16)

Q8. a) What is a Zener diode? (6)

b) Find the generated e.m.f./conductor of a 6-pole d.c. generator having a magnetic flux/pole of 64m Wb and a speed of 1000 rev/min. If there are 468 conductors, connected in six parallel circuits, calculate the total generated e.m.f. of the machine. Find also the total power developed by the armature when the current in each conductor is 50 A. (10)

Q8. (a) With an aid of a sketch briefly describe the important structural parts of 2-Stroke main Engine? How are different structural parts held together? (10)

(b) What is the function of Cross Head Guides? (6)

Q8. With reference to a fuel oil purifier:

(a) What are the reasons that may cause the purifier to overflow? (6)

(b) What are the reasons for the water carry-over with the oil? (5)

(c) What are the probable reasons for vibration seen during purifier starting? (5)

Q8. (a) Compare fixed pitch with controllable pitch propellers. (6)

(b) A ship of 12400 tonne displacement is 120 m long, 17.5 m beam and floats at a draught of 7.5 m. The propeller has a pitch ratio of 0.75 and, when turning at 100 rev/min, produces a ship speed of 12 knots with a real slip of 30%. Calculate the apparent slip, pitch and diameter of the propeller. The wake fraction w may be found from the expression. w = 0.5Cb - 0.05 (10)

Q8. i) Sketch and describe a fuel system diagram for a 2 stroke Marine diesel engine from storage / service tank to fuel injectors. Show the various components and fittings which are provided in the circuit. What is the purpose of mixing columns & autode-aerating valve? (16)

Q9. (a) What are the water pressure loads on the ship's hull. (6)

(b) The water plane area of a ship at 8.4 m draught is 1670 m². The area of successive water planes at 1.40 m intervals below this are 1600, 1540, 1420, 1270, 1080 and 690 m² respectively. Calculate the displacement in fresh water at 8.4 m draught and the draught at which the ship would lie in sea water with the same displacement. (10)

Q9. For 2-Stroke Marine Diesel Engine

a) Describe problems in achieving good lubrication of Cylinder Liner. (6)

b) What are the properties of good cylinder oil? (4)

c) What are the consequences of under and over lubrication of liner? (6)

Q9. Explain with a suitable diagram, the components of an auxiliary engine fuel valve? Briefly explain, the process of overhauling and pressure testing the fuel valve? (16)

Q9. a) Bunkering as a shipboard operation has its own significance. List out the important inspects of a bunkering operation including the preparation and precaution to be taken to ensure a safe operation. (8)

b) What does the Bunker specification include and how does it affect the engines adversely? Name at least three such ingredients that you expect in a Heavy Fuel Oil bunker and the effects on the engine operation. (8)

Q9. a) Sketch a schematic arrangement of a three-phase alternator with star connection. (6)

b) A 500V, 3-phase, star-connected alternator supplies a star-connected induction motor which develops 45kW. The efficiency of the motor is 88 percent and the power factor is 0.9 (lagging). The efficiency of the alternator at this load is 80 percent. Determine

a) the line current

b) the power output of the alternator

c) the output power of the prime-mover.  (10)