DG Shipping GP Exam – MARINE BOOK 28

Marine Engineering Oral Exam Questions and Answers for G.P. Rating Final Exam1. What are the main parts of a marine diesel engine?Cylinder, piston, crankshaft, camshaft, connecting rod, fuel injector, turbocharger, valves.2. What is the function of a crankshaft?It converts the reciprocating motion of the piston into rotary motion.3. What is the difference between 2-stroke and 4-stroke engines?2-stroke completes a power cycle in two strokes; 4-stroke in four strokes. 2-stroke is simpler and used in large marine engines.4. What is TDC and BDC?TDC: Top Dead Centre - highest point piston reaches. BDC: Bottom Dead Centre - lowest point piston reaches.5. What is the function of a piston?It moves up and down in the cylinder and transmits force to the crankshaft.6. What is the purpose of cylinder lubrication?To reduce friction and wear between the cylinder liner and piston.7. What are the uses of a fuel injector?It sprays fuel into the combustion chamber at high pressure for ignition.8. What is scavenging in a diesel engine?The process of removing exhaust gases from the cylinder and filling it with fresh air.9. Name different types of pumps used in the engine room.Centrifugal pump, gear pump, screw pump, reciprocating pump.10. What is the function of a bilge pump?To remove bilge water from the engine room and other compartments.11. What is the purpose of the sea water pump?To supply cooling seawater to engine systems.12. What is the function of the main engine?To generate propulsion power to move the ship.13. What is the purpose of an air compressor onboard?To provide compressed air for engine starting and control systems.14. How does a purifier work?By centrifugal force, it separates water and sludge from fuel oil or lube oil.15. What is the function of a fresh water generator?To produce fresh water from seawater using heat.16. What is the function of a turbocharger?To increase the air pressure supplied to the engine, improving efficiency.17. What is crankcase explosion and how is it prevented?An explosion inside the crankcase due to oil mist ignition. Prevented by regular maintenance and oil mist detectors.18. What is the role of the camshaft in an engine?To operate the intake and exhaust valves at proper timing.19. Name different types of coolers used on board ships.Lube oil cooler, air cooler, jacket water cooler.20. What is the function of a heat exchanger?To transfer heat between two fluids without mixing them.21. What is the function of an oil mist detector?To detect oil mist in crankcase to prevent explosion.22. Why are relief valves used in pumps?To prevent overpressure which may damage the system.23. What is the function of a starting air system?To provide compressed air to start the main engine.24. What is a governor and what does it do?It controls engine speed by regulating fuel supply.25. What is the function of a thrust bearing?To absorb axial thrust from the propeller shaft.26. What is the function of a stern tube?It supports and seals the propeller shaft where it exits the hull.27. How is fuel oil treated onboard?By heating, purifying and filtering to remove impurities.28. Name types of valves used in the engine room.Gate valve, globe valve, check valve, relief valve.29. What is the purpose of a bilge separator?To separate oil from bilge water before discharging overboard.30. What is the function of a pressure gauge?To measure and display fluid or air pressure in systems.31. How do you read a Vernier caliper?By aligning the main scale and Vernier scale for precise measurements.32. How do you read a micrometer?By reading the sleeve and thimble scales to measure small dimensions.33. What is a feeler gauge and what is it used for?It measures gap widths between two components.34. What is the function of a filter in a fuel oil line?To remove dirt and impurities from the fuel.35. What is overhauling of an engine?Complete inspection, cleaning, and replacement of worn parts.36. What is the function of the indicator diagram in an engine?It helps to analyze engine performance and diagnose faults.37. What are the causes of high exhaust temperature in a diesel engine?Overloading, late fuel injection, poor scavenging, dirty exhaust passages.38. What is the function of the expansion tank?To accommodate expansion of coolant and maintain system pressure.39. What is the difference between open and closed cooling systems?Open system uses seawater directly; closed uses freshwater in a closed loop.40. How do you maintain proper alignment of a shaft?Using dial gauges and proper alignment procedures during installation.41. What are the types of maintenance carried out on board?Preventive, corrective, predictive, and breakdown maintenance.42. What is meant by preventive maintenance?Scheduled maintenance to prevent failure and ensure smooth operation.43. What is the use of the workbench and vice?For holding and working on parts during repair or maintenance.44. What tools are used for tightening or loosening bolts?Spanners, torque wrench, pipe wrench.45. Name different types of spanners and their uses.Open-ended, ring, adjustable, box type – used for turning nuts and bolts.46. What is a hacksaw and what is it used for?It is a hand tool used for cutting metal pipes or bars.47. What is the function of a grinder?Used for grinding, cutting, and polishing metal surfaces.48. How is a lathe machine used onboard?For shaping metal parts by rotating them against cutting tools.49. What is the difference between a centrifugal and a reciprocating pump?Centrifugal uses impeller; reciprocating uses piston for fluid movement.50. What is the function of the lube oil system?To lubricate engine components and reduce wear and friction.51. What are common defects found in pumps?Leakage, cavitation, wear of impeller or seals.52. What is the procedure to clean strainers?Isolate the line, remove and clean the strainer mesh, and refit.53. What is backflushing?Reversing flow through a filter to remove blockage.54. How do you detect leaks in the engine room?Through inspection, leak detectors, and pressure drops.55. What is the use of a manometer?To measure fluid pressure, often in ventilation systems.56. Why is ventilation important in the engine room?To remove heat, fumes, and provide fresh air for personnel and machinery.57. What is the purpose of the jacket cooling system?To cool the engine cylinder and prevent overheating.58. What is the function of a thermometer and where is it used?To measure temperature in cooling water, oil, and exhaust gases.59. What is the procedure for sounding a tank?Lower a sounding tape or rod into the tank to measure liquid level.60. How do you take rounds in the engine room?Check machinery readings, leakage, unusual sounds, and record in log book.61. What is the function of a boiler?To generate steam for heating, cooking, and other machinery.62. What are the safety devices on a boiler?Safety valve, water level gauge, pressure gauge, fusible plug.63. What is blowdown in boiler operation?Removing water from boiler to control concentration of impurities.64. What is the difference between steam and hot water system?Steam is high temperature/pressure vapor; hot water is lower temperature liquid.65. What are the types of heat exchangers used on ships?Shell and tube, plate type, finned tube.66. What is the function of the bilge well?It collects unwanted water in the engine room for pumping out.67. What is the use of emergency bilge suction?To remove water quickly during flooding when normal pumps fail.68. What is the function of the engine control room?To monitor and control all engine room operations.69. What is the emergency shutdown procedure for an engine?Stop fuel supply, shut air system, inform bridge, and cool down systems.70. What checks are done before starting the engine?Oil levels, water levels, leaks, turning gear disengaged, alarms tested.71. What are the precautions before entering the engine room?Wear PPE, inform officer, ensure ventilation, avoid oil spillage areas.72. What is the function of a bilge alarm?To alert the crew when bilge water reaches a high level.73. What is meant by engine decarbonization?Cleaning carbon deposits from combustion areas of the engine.74. What is the function of a piston ring?Seals combustion gases, transfers heat, controls oil consumption.75. What are the symptoms of worn-out piston rings?Loss of compression, blue smoke, increased oil consumption.76. What is the difference between a liner and a cylinder?Liner is the replaceable sleeve; cylinder is the actual body.77. What is a starting air valve and how does it work?It opens to admit compressed air to start the engine.78. How does a mechanical seal work in a pump?It seals rotating parts using flat faces with tight contact.79. What is the function of a gland packing?To seal rotating shafts and prevent fluid leakage.80. What are the different methods of coupling two shafts?Flange, flexible, gear, and Oldham coupling.81. What is a foundation bolt?A bolt used to fix machinery to the ship's structure.82. What is the purpose of welding in ship repair?To join or repair metal parts permanently.83. What is the difference between MIG and Arc welding?MIG uses a wire and shielding gas; Arc uses electrode and no gas.84. What are the causes of abnormal engine noise?Loose parts, poor combustion, worn bearings.85. What is the function of a vibration damper?To reduce torsional vibrations in the crankshaft.86. What is a thrust block and where is it fitted?It absorbs propeller thrust and is fitted near the gearbox.87. What are the common materials used for marine engine parts?Cast iron, steel, bronze, and aluminum alloys.88. What is the function of an alternator?To convert mechanical energy into electrical energy.89. What is an emergency generator and when does it operate?Provides power when main generator fails, starts automatically.90. What is a hydraulic system used for on ships?For steering gear, hatch covers, winches.91. What is the purpose of a fuel oil booster pump?To increase fuel pressure before injection.92. What is a scavenging air manifold?A duct that distributes scavenging air to cylinders.93. What is a blow-by in a diesel engine?Combustion gases leaking past piston rings into crankcase.94. How is the crankcase inspected safely?Shut down engine, ventilate, check for gases, open carefully.95. What is the use of indicator cock?To attach indicator diagram equipment or release pressure manually.96. What is a crosshead and what is its function?Connects piston rod to connecting rod, converts reciprocating to rotating motion.97. What are common engine room emergencies?Fire, flooding, lube oil leakage, machinery failure.98. What actions are taken in case of lube oil leakage?Stop engine, isolate leak, report, clean spillage, repair.99. What are the reasons for engine overheating?Cooling water failure, overload, poor lubrication, dirty heat exchanger.100. What routine checks are done on marine diesel engines?Oil level, coolant level, leaks, noise, vibration, exhaust color.

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