QUESTION BANK MARINE ENGINEERING KNOWLEDGE MOTOR PART-1

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Q a) If an auxiliary diesel generator over speeds and runs away while off the load, explain: –

i. How it can be stopped?

ii. What is likely to be the reasons for the failure?

b) Give details of what checks are made after the machine has been stopped:

i. Mechanically

ii. Electrically

Q With reference to bottom end bolts for medium speed four stroke engines:

a) Explain why bottom end bolts will ultimately fail under the normal operating conditions.

b) Identify the features included into bolt design to inhibit failure.

c) Explain how bolt failure may be fastened when the maintenance is done.

d) Describe, as a 2/E, your strategy for preventing the bolt failure.

Q a) Describe the precaution necessary during the initial running-in of an Auxiliary Engine run on the H.F.O, which is newly installed or has had a major overhaul.

b) Explain the possible causes of the oxidation of the lubricating oil.

c) State the frequency with which oil samples should be taken for the analysis.

Q With reference to the auxiliary diesel engines, suggest probable causes that would create EACH of the following conditions & state how they would be rectified:

a) Knocking

b) Loss of power

c) Loss of lubricating oil pressure

Q An Auxiliary engine shows the tendency to hunt to such an extent that the engine speed variation prohibits the connection of the machine to the switch board.

a) Discuss the possible causes of the hunting.

b) Explain how the problem of hunting can be rectified.

Q With respect to the medium speed auxiliary power generating 4 stroke medium speed diesel engines:

a) Explain how the cylinder liners are effectively lubricated.

b) Explain how the standby engine is maintained in a condition ready to be started immediately.

c) Describe how the engine is changed from HFO operation to the DO operation when running.

Q The emergency generator for a 300 people passenger ship has to be completely renewed. The company contracted for work has no previous experience of the marine installation. You as the 2/E have been requested to write the specification for the type & installation of the generator. Outline your proposal for the type of engine. State the necessary requirement for the approval & certification needed.

Q With respect 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 the expansion.

c) Describe how boiler carryover affects super heater effectiveness & condition.

Q Describe the method of setting the safety valves of an exhaust gas boiler at sea.

a) State the limits in terms of percentage above maximum design working pressure for the setting safety valves.

b) State the formality required when Chief engineer sets the safety valves.

Q a) Draw a line diagram of a complete feed water system for an auxiliary boiler, labelling all the principal items and showing the direction of flow in all lines.

b) Explain how the feed supply to boiler is regulated.

c) State what means are provided to prevent oil contamination of the feed water.

Q Boiler automatic combustion control has failed during operation of boiler. Explain:

a) Procedures to operate boiler in an emergency

b) Action plan to investigate, rectify & bring system to normal from boiler emergency operation.

Q Describe how to ‘blow down’ & ‘open up’ the primary side of a double evaporation boiler for inspection. Identify with reasons those parts, which normally require close examination during internal inspection, on secondary side.

Q Describe in detail the causes and conditions that:

a) Create an explosive atmosphere in a crankcase.

b) Initiate a primary explosion.

c) Propagate a secondary explosion

State how hazardous conditions can be avoided.

Q Discuss the precautions which can be taken to minimize the possibility of a diesel engine crank case explosion & the transmission of the dangerous flame into the machinery space:

a) By design & equipment

b) By operating personnel

Q With reference to the crankcase diaphragm glands:

a) Explain why effectiveness deteriorates in service.

b) Describe the procedure for the renewal of parts so that efficiency is restored & rod scoring is avoided.

c) Describe how effectiveness is restored if spares are unavailable.

d) Explain the functions of the upper & lower sections.

Q Describe clearly how you would deal with a fire in the scavenge space of a marine diesel engine? Explain the causes of such fires and state the measures which can be taken to limit their occurrence?

Q Explain with sketches the various fitments/methods by which the crankcase of the large marine diesel engine is

protected.

Q a) Outline the possible events leading to an explosion in the crankcase of a diesel engine.

b) Describe, with the aid of the sketch, the operation of a oil mist detector.

c) State how overheating might be indicated other than by a mist detector.

d) Explain how the severity of a crankcase explosion is limited.

e) State the standing orders you as Chief Engineer would issue in the event of the mist detector alarm actuating.

Q With reference to scavenge spaces of the  main engines, give reasons for the following faults:

a) Lubricating oil accumulation

b) Scavenge fires

c) Water accumulation

d) High air temperature

e) Lubricating oil accumulation.

Q How is the cylinder lubricators fitted in a large marine diesel engine that has a water jacket? Where is the location of the lubricator outlet in relation to the piston rings on the piston? Why is this position necessary?

Q Sketch & describe a flywheel that would be installed to a large marine diesel engine. Show in the sketches how it is fitted & secured. What is the purpose of the flywheel? Recently some engine makers have considerably reduced the size of the flywheel. Explain how this can be done.

Q Describe with aid of sketches the following types of bedplates as used for a large I.C. engine:

a) Bedplate cast in section

b) Fabricated steel Bedplate

State the stresses to which these bedplates are subjected & explain how bedplates are secured to the hull of the ship.

Q With reference to main engine tie rods explain:

a) Function

b) Effect on main engine in case slack

c) Identifying slackness

d) Material

e) Tightening procedure

Q Describe the procedure in lining up an engine bedplate, main bearings, gear box, thrust block, propeller shafting & tail-end shaft, assuming this to be a new ship?

Q With reference to the large fabricated bedplates explain:

a) With reasons, why longitudinal strength & rigidity is important in spite of the contributions made by ship’s structure.

b) With sketches show how the combustion loads imposed on piston & cylinder heads are transmitted to, & absorbed by bedplates.

Q With reference to the behavior of fabricated bed plates & frames in service:

a) Identify the various forces imposed simultaneously upon them?

b) Explain how engine structure withstands these forces?

c) State how these forces are transferred to ships structure?

Q With reference to the cylinder lubrication of a large slow speed engine:

a) Explain with the aid of a sketch, the operation of a cylinder lubricator indicating how quantity adjustments may be done.

b) State the advantage of the relative vertical positions of  the cylinder lubricating quills used by different engine manufactures.

c) Describe TWO features that assist the spread of the oil.

d) Describe how you, as second Engineer would assess liner & decide when renewal is necessary.

e) State the effect of low Sulphur fuels on cylinder lubrication.

Q Main engine  no. 2 unit de carburization was carried out. On piston inspection, following faults were observed:

a) Cracking and burning of upper part of crown

b) Cracking in piston ring grooves

c) Explain the causes & how it can be minimized in future.

Q The failure of one tie rod has occurred in a 2 stroke marine diesel engine. Explain:

a) How could this failure be detected?

b) Effects of running engine with a broken tie rod & what preventive measures can be taken?

Q It is noted in engines burning heavy fuel that the top of the piston crown may waste and gradually burn away. What is done to rectify this condition?

Q Give a list of the properties or tests by which distillate and blended fuels may be specified or decisions be made on their fitness for use. Name the properties or the constituents that may be found in a blended fuel having a high viscosity and high carbon content. Explain how they may cause problems in engine operation.

Q Explain why the use of the residual fuels for the operation of large slow speed or of medium speed engines, may be responsible for the following problems with turbocharger nozzles, shrouds and blades and how in each, the problem may be minimized :

a) Build-up of deposits

b) Hot corrosion

c) Erosion

Q Discuss the effect on the main engine operation of the use of low grade fuel & in particular refer to causes & prevent of:

a) Liner wear

b) Crankshaft corrosion

c) Corrosion of exhaust space.

Q With reference to burning of the residual fuel:

a) State what is meant by ignition quality.

b) Describe how fuel pumps are adjusted to enable the engine to burn fuels of different ignition qualities.

c) State with reasons what other adjustments may be required with fuel pumps after a period of time in service.

d) Explain the consequences of not making adjustments mentioned in the answer to (b) & (c).

Q Given that ignition quality of fuels bunkered at different ports may vary:

a) State how variation of the fuel quality may be detected during dieting engine operation.

b) Describe a fuel pump arrangement, which will adjustment to compensate for the variation of the fuel quality.

c) Explain the possible consequence of using fuel with good ignition quality without compensation.

Q Explain in detail the main engine problems that may arise due to the fuel catalytic fines & the best shipboard practices that may be adopted to combat the problem.

Q The fuel consumption of your ship suddenly increased for no apparent reason. Describe how you would investigate the problem & deal with it.

Q a) Explain the term ignition quality as applied to the marine fuel oils.

b) State, with reasons, the properties of the fuel which can influence ignition quality.

c) State how an unexpected change in the ignition quality would manifest itself in an operating engine.

d) Explain in detail how an engine would be adjusted in order to burn the fuel having a different ignition quality.