- Which standards govern the specifications for supply of Residual Marine Fuels and Distillate Marine Fuels onboard merchant ships?
- ISO 3012:1999
- ISO 3648:1996
- ISO 8216-1:2010
- ISO 8217:2010
- Crank web deflection readings will give a positive indication of
- worn main bearing journals
- torsional stress deformation
- slack thrust bearings
- bearing shells shim dimensions
- ESD stands for which type of boiler
- External superheater D-type
- Emergency shutdown Boiler
- Extreme Superheat type
- External Superheat De-superheater type
- The advantage of tie rods over an engine without tie rods is that:
- The engine is very easily aligned after any misalignment has taken place between different components of the engine
- The engine doesn’t require thrust pads for transmission of thrust to the ship???s hull as the same is being taken care of by the tie rods
- The engine components are much lighter leading in overall reduction is engine weight with a high power generation with the elimination of fatigue stresses
- There are no advantages of engines with tie rods, because tie rods require regular maintenance and replacement like connecting rods and overall engine becomes more expensive to operate
- Which of the following is an example of a solid bearing?
- Piston pin bushing
- Turbo-generator turbine bearing
- Spring bearing
- Thrust bearing
- In order for microbiological growths to thrive in a fuel tank it is necessary for
- high temperatures to exist
- low temperatures to exist
- small amounts of water to be present
- large amounts of water to be present
- Marine boilers burning H.F.O. face a problem of cold corrosion due to high sulphur content. The minimum flue gas temperature within any boiler part is kept above due point of H2SO4. The actual dew point of H2SO4 in flue gases depends on the:
- Boiler furnace temperature
- Ambient air temperature
- Boiler operating pressure
- HFO sulphur content and moisture in combustion air
- The purpose of an air cooler in a supercharging system is to:
- Reduce temperature of supercharged air in order to condense and remove maximum possible moisture from the air prior entry to the engine
- Reduce the temperature of the supercharged air in order to increase the density & also to cool down below dew point to remove moisture from air prior entry to the engine
- Cool supercharged air to increase its density such that the dew point is not reached to avoid entry of moisture into the engine
- Cool supercharged air to increase its density and also to keep the peak temperature and exhaust gas temperature within limits
- Use of Halon as fire extinguishing medium has been discontinued because
- It is highly toxic
- It is expensive
- It has high Ozone depleting potential
- It leads to acid rains
- In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low-alloy steels because
- the beveled edges of the intake valves provide for self-centering during seating
- intake valves utilize stellite-coated valve seat inserts which reduce wear
- the volume of air passing through intake valves is less than the volume of air passing through exhaust valves
- intake valves are less affected to the corrosive action of exhaust gases
- Why is it essential to renew turbocharger bearings after a preset number of hours of running even if the bearings are in seemingly perfect condition?
- Because they are prone to failure due to prolonged exposure to high temperature conditions.
- Because they are subject to cyclic loading and are prone to failure due to metal fatigue
- It is not essential to renew if condition monitoring suggests perfect condition.
- Lube oil contamination is bound to occur and affect the condition of the bearings
- Which of the following statements is true?
- The rotary vane type steering gear generally operates at higher oil pressures than the ram type.
- The ram type steering gear generally operates at higher oil pressures than the rotary vane type.
- Both ram type and rotary vane type steering gears generally operate at similar oil pressures
- None of the above
- Modern marine turbochargers use a ___________ type of compressor
- Radial flow
- Axial flow
- Mixed flow
- Turbulent flow
- Which of the following is a disadvantage of water as cooling medium for pistons, when compared to oil?
- Chemical treatment is required
- Higher thermal stresses in piston
- Piston of more complicated design
- All of the above
- How is the concentration of dissolved oxygen in the feed water of an auxiliary boiler maintained at acceptable limits?
- Feed water is cycled through a DC heater.
- Feed water is treated with phosphates.
- Oxygen is liberated in the three-stages of feed water preheating.
- Oxygen is liberated by maintaining the highest practical feed water temperature
- In a 2-stroke marine diesel engine if the o-ring for Jacket cooling water sealing is leaking then
- The water will leak directly into the crankcase
- The water will leak into the under piston space
- The water will come out through tell-tale hole provided between the two o-rings
- The water will come out from the top of cylinder jacket
- The lube oil pump used in a diesel engine is a
- volute pump
- centrifugal pump
- diaphragm pump
- gear pump
- Prior to lighting off a cold automatically fired auxiliary boiler, you should
- check and regulate the water level
- close the air cock once fires are lit
- blow down the gage glass
- crack the steam stop to assure protective steam flow
- Steam temperature control for the ESD-II boiler is achieved by :
- Fitting a de-superheater between 1st & 2nd passes of superheater
- Fitting an attemperator between 1st & 2nd passes of superheater
- Gas dampers in boiler uptake
- Bypassing the superheater
- The coating which is provided on the valve stem of exhaust valves of modern marine diesel engines is of:
- If the combustion control system of an automatically fired auxiliary boiler fails to sustain burner ignition after a normal shutdown, you should check for a/an uscg 56
- faulty photocell detector
- low steam pressure
- high voltage on the ignition electrode
- open air damper
- Which of the following statements is true, about slow speed engines?
- A scavenge fire can lead to a crankcase explosion
- A scavenge fire can lead to deformation of diaphragm plate
- A scavenge fire can lead to damage to tie rods.
- All of the above
- For a two stroke engine two o-rings are provided on the liner. The function of the top o-ring is to ________ and function of the lower o-ring is to _________
- Seal jacket cooling water; act as secondary seal in case 1st o-ring leaks
- Seal jacket cooling water, Seal scavenge air
- Seal scavenge air, Seal Jacket cooling water
- Seal combustion gases, Seal jacket cooling water
- Even if there is an oil mist concentration inside a crankcase, and there is also a hot spot, crankcase explosion will only take place when
- The hot spot provides the ignition temperature for the oil mist concentration
- When the oil mist – air mixture is in the flammable range
- Both A and B
- None of the above
- Which of the following conditions is responsible for the fuel oil to atomize when using a steam atomizer in an auxiliary boiler?
- Expansion of the steam in the furnace.
- Expansion of the steam in the whirling chamber.
- Expansion of the steam in the orifice plate.
- All of the above
- Some 4-stroke engines are fitted with a rotorcap on the cylinder head valves. For what reason?
- Rotate the inlet valve during operation.
- Distribute the exhaust gas or the air inlet better to improve combustion.
- Improve the scaling surface function, increase the service time of the exhaust valve in the engine
- To prevent the valve spindle from sticking
30. Shaft tunnel requires
b) escape trunk
c) water tight door
d) all the above