Q For a fully automated provision refrigeration system incorporating a number of rooms:
a) Explain how each room temperature is set.
b) Describe the sequence of the events following a demand for the increased refrigerant flow from one room.
c) State with the reasons the devices installed into the system to protect the machinery & equipment against malfunction.
d) State how satisfactory operation of the plant can be achieved.
Q a) With aid of a simple sketch, explain the “trouble spots”/ “operation” of a basic air conditioning unit.
b) With the help of sketch, explain the following:-
i. How the problem of increase in humidity of the cooled air is overcome?
ii. How discomfort caused by the excessive drying effect of the heater air is overcome?
Q With reference to refrigeration system on board ship, enumerate the following:-
a) Consequence of lubrication oil pressure low.
b) Procedure for charging the system.
c) Changing of shaft seal of the compressor.
d) Reason of ice formation on the return line.
Q a) For an expansion valve as fitted in a refrigeration system, name operational that may cause a high pressure cut-out operate?
b) Describe the preventive maintenance schedule to prevent reoccurrence of this situation stated in (a).
Q a) Sketch & describe the high pressure cut out for a refrigeration unit.
b) The refrigeration compressor has cut out due to the operation of the H.P. cut out. State the possible causes.
Q Explain in detail the preventive maintenance to be carried out for shipboard air conditioning system.
Q It is detected that the refrigerating compressor on board your ship has not been properly aligned with the motor, after a major overhaul ashore. Enumerate how the misalignment is detected and remedied.
Q For a vapour compression refrigeration machine, state how EACH of the following faults are indicated and how they are remedied:
a) Air in the system
b) Moisture in the system
c) Undercharge
d) Overcharge
Q Give possible ways to detect EACH of the following conditions occurring in a fully charged domestic refrigeration unit:
a) Excessive high pressure at the compressor discharge.
b) Very low pressure at the compressor suction.
c) Continual starting & stopping of the compressor.
d) Machine running for long periods but unable to adequately lower refrigerated space temperatures.
e) Compressor operating noisily.
Incase (i.e. from “a” to “e”), please enumerate the remedial action.
Q In cold climatic conditions, it was required to provide accommodation heating:
a) State causes & remedies for following:
i. Drying effect of air causing discomfort
ii. Suffocating effect in accommodation
b) Explain with the help of a sketch how humidity is maintained?
Q With regard to keeping the gas side of boilers in good condition, discusses maintaining each of the following:
a) The mechanism of the combustion, stating the factors which are important to good combustion
b) Oil fuel treatments
c) Soot removal equipment
Q a) Discuss the possible reasons for the following changes in boiler water test results, and state what actions should be taken in each case:
i. Reduction in total dissolved solids & chemical reserves
ii. Reduction in the phosphate reserve, with increase in chlorides & total dissolved solids.
iii. Reduction in the alkalinity reserve only.
iv. Increase in oxygen level only.
b) State why the complete results of the boiler tests are entered into a data retrieval system rather than a note being made of any particular result which may be outside set limits.
Q An auxiliary boiler is periodically unattended & equipped with alarms to cover low water level, high steam pressure, and air & flame failure.
a) State why & how fuel to the burners is automatically cut off under alarm conditions of the water level, steam pressure, air & flame failure.
b) Describe how & when each of the above alarms is tested without damaging the boiler.
Q a) Describe how an auxiliary boiler would be blown down & opened up for inspection. State the Precautions which should be taken during the inspection & when boxing up the boiler for service.
b) Which parts require particularly close attention when opened up and describe the procedure for the setting of safety valves.
Q a) State the indication that a main boiler generating tube is leaking:
i. When the amount of the leakage is small?
ii. When the amount of the leakage is large?
b) If boiler tube failure is evident, describe the actions necessary.
Q Boiler automatic combustion control has failed during the operation of boiler. Explain:
a) Procedures to operate boiler in an emergency.
b) Action plan to find, rectify & bring system to normal.
c) Instruction to watch keeping officers with regard to the operation of boiler in emergency mode.
Q a) Describe THREE different patterns of tube used in exhaust gas boilers
b) Give 2 reasons why a tube is condemned.
c) Describe how it is replaced by the spare tube.
d) Suggest with reasons the possible consequences of allowing an exhaust gas boiler to run dry during full power operation of the M/E.
Q Rapid increase in total Dissolved solids of boiler water is observed. Explain:
a) Your action to find the cause of such increase.
b) Steps to bring down the TDS & operate the boiler safely in an emergency.
c) Permanent collective action taken to bring the boiler to the normal condition
Q Describe how the following conditions are prevented in auxiliary boilers:
a) Feed contamination by the oil from heating coil drains
b) Internal corrosion
c) Furnace blowback
d) Uptake fire
Q An auxiliary boiler water level control system has a differential pressure transmitter as the detecting element for water level.
a) Sketch & describe such an arrangement.
b) If the transmitter was damaged explaion how a replacement unit would be calibrated.
Q With reference to a cylindrical boiler which has undergone major repairs, explain:-
a) How is the boiler prepared for carrying out hydraulic test?
b) What is the test pressure to which boiler is subjected to?
c) What inspection should be made before, during & after the test?
Q Describe how you would test boiler water for:
a) Alkalinity
b) Chlorides
State the values obtained from the tests that would be considered suitable for a water tube boiler. If the test results were unsatisfactory, what remedial action would you take?
Q Under continuous survey of machinery, bottom end bearing of a large slow speed engine is due for survey:
a) As a 2/E explain the procedure involved in the complete inspection of a bottom end Bearing?
b) List the precautions to be taken?
c) Indicate the reasons for the possible defects, which could be encountered, & state how they may be rectified?
d) What tests are earned out on completion of the survey & re-assembly?
Q The vessel of which you are 2/E suffers grounding. Describe the survey & inspection which you will carry out at the next dry docking of the vessel in a foreign port?
Q a) Explain in detail how an in water survey is carried out.
b) State the conditions to be fulfilled before an in water survey is acceptable to the survey authority.
c) Prepare a list of the items in order of importance that the underwater survey authority should include.
Q a) Describe the hull examination that should be carried out on a ship in dry dock, making special reference to essential maintenance & repairs that can only be carried out in dry dock.
b) Prepare a list of the items in order of importance that are required to be surveyed in the drydock.
Q Discuss the advantages and disadvantages of adopting the following policies for maintenance of main & auxiliary diesel engines.
a) Planned maintenance.
b) Condition monitoring.
c) Periodic replacement of components.
Q Describe the in-water survey to the classification society requirements of the external underwater structure of a very large crude carrier.
Q a) Describe the events leading to a crankcase explosion.
b) State how overheating might be indicated other than by a mist detector.
c) State how severity of the crankcase explosion is limited.
d) Emission of the flame has in the past caused severe burns to the personnel present during a crankcase explosion. Despite the addition of the flame traps. Discuss the procedure in the event of overheating being indicated.
Q a) State the common causes of scavenges fires.
b) List the indications that a scavenge fire is in progress.
c) State the immediate action to be taken in the event of the scavenge fire.
d) List with reasons the checks & precautions required before an engine is put back into service following a scavenge fire.
Q Enumerate the probable causes of the crankcase explosion & give a general description of a system designed to detect the presence of an explosive mixture in a crankcase.
Q Describe in detail the causes & 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 Give a general description of a system designed to detect the presence of an explosive mixture in a crankcase? What routine attention such systems needed to prevent malfunctioning.
