Le test comprend 80 questions aléatoires.
Total de questions sur ce sujet : 95
Marine steam boilers are protected with a number of safety features which are designed to prevent damage to the boiler due to overheating or overpressure. How is this protection achieved when a very low water level condition (often referred to as low low level) develops during operation?
All burners are automatically and immediately shut off.
The main and auxiliary feed control valves open fully while all burners continue to operate.
All but one of the burners is shut off with the remaining burner being reduced to minimum firing.
All burners are automatically set at minimum firing rate.
What will you do if you have a flash-back during gas welding?
Use your portable fire extinguisher.
Close the valves oxygen first.
Cool the bottles down with water.
What may be the cause of black smoke from the funnel?
The fuel oil has not been adequately heated.
Incomplete combustion owing to wrong mixture of air and oil.
The fuel oil is of inferior quality.
An electrically operated turning machine is used during repairs while the engine is running.
What is the main reason for sometimes having a separate forced lubrication system for the camshaft on large cross head engines?
To prevent any fuel leakage from the high pressure fuel pumps contaminating the oil in the main lubrication system.
Because the camshaft system uses a different grade oil from that used in the main lubrication system.
Because the camshaft lubrication system has a lower pressure than the main lubrication system.
During inspection of a high pressure fuel pump for a medium speed diesel engine it is observed that the upper leading edge and the lower helical edge of the pump plunger have suffered from erosion damage. Select the correct action to take to remedy this from the options given.
Renew the plunger and barrel insert as a pair.
Replace the complete pump with a new or reconditioned spare.
Smooth away the damaged area with a grinder and polishing stone and refit it.
Renew only the plunger if the barrel appears undamaged.
At what interval should boiler water testing usually take place?
The main engine is running steady with exhaust gas temperature approximately 350 °C. What is the normal slow down temperature for exhaust gas deviation from average?
What is meant by the term “two stage air compressor”?
A compressor in which the compressed air from the first stage is further compressed in the second stage before being delivered to the air receiver.
A compressor in which the air is delivered to two separate air receivers each at different pressures.
A set of two compressors. The first compressor delivers low pressure air to an air receiver. The second further compresses the air for delivery to the working range.
A two cylinder compressor in which half of the air is compressed in one cylinder and half in the other.
The main engine is running steady. What is the normal slow down temperature for the main bearing metal “Oil outlet temperature”?
What is the reason for fitting “Rotocaps” to the cylinder head valves of some 4-stroke diesel engines?
To extend the service life of valves by giving even heat and wear distribution.
To help clear the cylinder of exhaust gas by spinning the exhaust valve during opening.
Rotate the inlet valve during operation to improve air turbulence in the cylinder.
If you are going to enter the engines crankcase (go inside), how will you secure the engine after you have closed the main starting air valve?
Engage the turning gear on the engine.
Close the instrument air supply.
Keep a man posted in the control room to watch that nobody tries to start the engine.
Close absolutely all valves on the starting air bottle.
What is the purpose of refractory linings in an oil fired steam boiler furnace?
To prevent excessive furnace heat losses and protect tubes and other fittings from overheating.
To ignite the burner during automatic operation.
To support the steam drum.
To give added strength to the furnace.
What characterizes a 2 stroke diesel engine?
A 2 stroke engine has an ignition every time the piston reaches its top position.
A 2 stroke engine always has 2 or more turbochargers.
The piston always has a short skirt.
A 2 stroke engine has an air inlet valve in the cylinder cover.
A power card taken from a diesel engine cylinder using a mechanical indicator has a flat top. Which of the possible actions given in the options is most likely to correct this irregularity on the power card?
Shorten the cord for the indicator drum drive.
Change the indicator spring for one with a higher rating.
Lubricate the indicator piston and cylinder.
Lengthen the cord for the indicator drum drive.
When referring to onboard oil treatments using a centrifuge, what is meant by the term purification?
Separation of two insoluble liquids with different densities, and the removal of solids in the same process.
Separation of one insoluble liquid from another.
It is a general term applied to a process for cleaning oil using a centrifuge.
Separation of solid contaminants from a liquid during the process.
What would be a typical separating temperature range for purifying mineral oil based lubricating oil in a centrifuge?
During inspection of a high pressure fuel pump for a medium speed diesel engine it is observed that the upper leading edge and the lower helical edge of the pump plunger have suffered from erosion damage. Select the correct action to take to remedy this from the options given.
Renew the plunger and barrel insert as a pair.
Replace the complete pump with a new or reconditioned spare.
Smooth away the damaged area with a grinder and polishing stone and refit it.
Renew only the plunger if the barrel appears undamaged.
When planning bunkering operations it is preferable to arrange for the new fuel to be bunkered into empty or nearly empty tanks whenever possible. What is the main reason for this?
To minimise the risk of incompatibility between different fuels.
So that the sulphur content of each fuel is known.
To make it easier to calculate the quantity of fuel taken onboard.
To minimise the risk of microbial contamination of the fuel.
Your vessel has a controllable pitch propeller. The engine can be started when the propeller pitch is:
What refrigerant temperature would you expect to find at the compressor suction of an air conditioning system?
In a purifier assuming the separating temperature is correct, what is the probable cause of the processed oil containing water?
The back pressure at the clean oil outlet is too high.
The gravity disc is too large.
The throughput is too low.
The gravity disc is too small and/or the flow rate is too high.
A compressed air supply system has two automatically controlled air compressors. When demand is high both compressors are needed to meet the delivery requirements. What is the best method for controlling the supply from these compressors to meet a varying, but intermittent demand?
Sequential start initiated by pressure switches set at different switching pressures.
One compressor running continuously with the other on standby.
Start and stop of the compressors controlled by timer switches.
Continuous running of both compressors and the use of unloading devices.
If a refrigeration system contains air, how would you remove it from the system?
Pump the system down to the condenser, continue cooling water flow until the condenser is at the same temperature as the cooling water and vent off the air from the top of the condenser.
Stop the compressor and vent the air from the crankcase.
Pump the system down to the evaporator and keep the fan running until the evaporator is at ambient temperature and vent off the air from the top of the evaporator.
What will you do if the PH-value in the boiler water is under 7?
Increase the dosage of chemicals, and take new test of the water.
Blow the boiler and renew some water.
Decrease the dosage of chemicals, and take new test of the water.
The main engine is running steady. What is the normal slow down/alarm pressure for “Fresh cooling water across engine”?
Which one of the statements given in the options is correct in relation to the maintenance and adjustment of 4-stroke medium speed diesel engines?
Both the top and bottom shells of a bottom end bearing should be inspected as they can wear due to load reversal during the engine operating cycle.
The piston ring groove clearances for the oil control ring are unimportant as this ring does not form part of the gas seal.
Liner wear of up to 3 % of the bore size is generally acceptable for continued service.
Timing of inlet and exhaust valves can be correctly set by varying the tappet clearance.
With reference to non-VIT diesel engine high pressure fuel pumps that have helix control, how is the timing of fuel injection normally adjusted?
By raising or lowering the pump plunger relative to the pump barrel.
By rotating the pump plunger relative to the pump barrel.
By changing the governor output signal.
By changing the opening pressure setting for the fuel injection valves.
In a low pressure auxiliary boiler, if after testing the water you found the P. alkalinity to be 450 ppm CaCo3, what action would you take?
Blow down boiler and reduce dosage.
Why are hypochlorite based treatments used on some sea water cooling systems?
To prevent biological growth in the system.
To reduce sediment build up in the system.
To prevent corrosion of the system.
To increase the heat transfer capacity of the system.
Part of the outer surface of a refrigeration compressor crankcase and the refrigerant return line near the compressor ice up heavily during normal operation. Which of the options given is the most likely cause of this problem?
The superheat control setting for the thermostatic expansion valve is set too low.
The filter drier unit in the liquid line is partly blocked.
The seawater flow control valve for the condenser is faulty allowing insufficient cooling water flow.
The oil separator is not functioning correctly and is allowing lubricating oil to pass into the system.
The main engine is running steady. What is the normal slow down temperature for scavenge air boxes “Fire alarm”?
Tests on the water in a low pressure boiler show the chloride level is 500 ppm. What action should be taken?
Increase feed water temperature.
Decrease dosage of treatment chemicals.
Increase dosage of treatment chemicals.
Blow down boiler and check the condenser for leakage.
The main engine turbocharger speed has increased during the night while operating in UMS mode. From the options given, what is the most likely cause of this?
The engine load has increased due to external factors such as current and wind.
The governor signal has been overridden by the bridge.
The engine load has reduced due to external factors such as current and wind.
The engine is operating on a different grade of fuel.
Why are crankcase heaters fitted to some refrigeration system compressors?
To prevent refrigerant condensing in the crankcase when the compressor is stopped.
To control viscosity of the lubricating oil.
To prevent ice from forming on the compressor casing.
To boil off any water from condensation in the crankcase.
Part of the outer surface of a refrigeration compressor crankcase and the refrigerant return line near the compressor ice up heavily during normal operation. Which of the options given is the most likely cause of this problem?
The superheat control setting for the thermostatic expansion valve is set too low.
The oil separator is not functioning correctly and is allowing lubricating oil to pass into the system.
The seawater flow control valve for the condenser is faulty allowing insufficient cooling water flow.
The filter drier unit in the liquid line is partly blocked.
In accordance with SOLAS and other international regulations, certain important machinery functions, such as operation and control of the steering gear and propulsion machinery, must be tested at specified times. When should these tests be carried out?
Only at stand by engines.
Only following maintenance.
Prior to arrival and departure from port and following maintenance.
When checking the closed butt gap clearance of new piston rings prior to fitting onto the piston it is normal to try the rings in the liner so that the gap can be measured. From the options given select the best part of the liner to use to carry out these checks.
Near mid-height of the liner.
Near the top of the liner.
Just above the scavenge ports.
Near the bottom of the liner.
How is the effective delivery stroke of a helix type fuel pump for a diesel engine controlled to increase or decrease the quantity of fuel delivered?
Rotation of the plunger by the fuel rack from the governor signal.
The fuel booster pump delivery pressure.
The fuel rail pressure relief valve setting.
The fuel injector setting.
The auxiliary boiler for the supply of low pressure heating steam has an automatic combustion control which operates on a two step control principle. The boiler fails to attempt to start up during a period of normal operation even though the steam pressure has fallen below the set point. What is the most likely cause of this fault?
The pressure switch for low steam pressure is faulty and fails to close.
The electrical supply for the control system is isolated.
The pressure switch for the combustion air supply is faulty and remains open.
The photocell for detecting flame on is dirty.
A piston ring set for a trunk piston engine often includes a slotted ring tensioned by an internal spring. What is the purpose of this type of piston ring?
It is a ring to seal the crankcase from the combustion chamber.
It is an oil control ring.
It is the lowest compression ring.
When checking the closed butt gap clearance of new piston rings prior to fitting onto the piston it is normal to try the rings in the liner so that the gap can be measured. From the options given select the best part of the liner to use to carry out these checks.
Near mid-height of the liner.
Near the top of the liner.
Near the bottom of the liner.
Just above the scavenge ports.
The duty engineer notices that there is full flow through overflow line observation glass to the fuel oil overflow tank. What action should be taken?
Stop all F. O. transfers and other fuel operations immediately and check all fuel tank levels.
Get a crewman to sound the overflow tank at frequent intervals and report to the duty engineer when it is nearly full.
Check the levels in all the fuel oil tanks.
Start the fuel oil transfer pump to pump out the overflow tank.
During the cycle of a four stroke diesel engine there is a load reversal on the bottom end bearing when the load transfers from the upper part of the bearing to the lower part. What is the main cause of this load reversal on a modern, turbocharged, medium speed diesel engine?
The lack of gas load to oppose the inertial forces generated during the exhaust stroke.
The light alloy materials used for the piston skirt.
The inertial forces generated during the upward strokes of the piston (compression and exhaust strokes).
The suction effect on the piston during the air intake (induction) stroke.
How is the condenser in a fresh water evaporator normally cooled?
What is the purpose of a scum valve often fitted to a steam boiler?
To allow removal of any oil or scum which collects on the surface of the water in the boiler steam drum.
To allow removal impurities from the boiler feed-water.
To allow removal of oil from the surface of the feed water tank.
To allow removal of sludge and mud which may collect in the bottom of the boiler water drum.
One cylinder of a diesel engine is operating with a high exhaust gas temperature. From the options given, select the one most likely to cause this condition.
Cylinder lubricating oil supply rate to the engine is excessive.
Water leakage into the cylinder.
Fuel injection valve opening pressure is too low.
The charge air is delivered to the engine at too high a temperature.
When should adjustment to the fuel injection valve spring tension be made?
Only on the fuel injection valve test rig.
During engine operation when cylinder maximum pressures need to be balanced.
During engine operation when cylinder exhaust temperatures need to be balanced.
During engine operation when fuel timing to individual cylinders needs to be adjusted.
What effect would a blocked steam connection to a boiler water level gauge glass have on the visible water level in the glass?
The level in the glass would be higher than the actual level in the boiler.
There would be no or very little water shown in the glass because it would be air locked.
The level in the glass would be less than the level in the boiler due to the water in the glass evaporating into the empty steam space.
What action is required if boiler water tests confirm a pH value of less than 9?
Increase the dosage of alkalinity treatment chemicals until the pH value is back within normal range.
Reduce the dosage of alkalinity treatment chemicals until the pH is back within normal range.
Blowdown the boiler and refill with good feedwater.
A power card from a slow speed diesel engine cylinder is abnormal with a low height and the body of the diagram thicker than normal. What is the most likely cause of this?
Scavenge pressure is too high.
Partially blocked fuel injection valve.
You are in charge of a night bunkering operation. The delivery rate from the supplier is high and you are filling six tanks simultaneously. You lose track of the progress of the operation and feel that you are losing control of the situation. What action should you take?
Stop bunkering, and establish facts, before bunkering is resumed.
Open more tanks to slow down the filling rate of individual tanks.
Prepare yourself and the crew for an overflow.
Request a reduction in the delivery rate to try and gain some time.
What would be a typical setting for the low lubricating pressure trip for a refrigeration compressor?
At what pH-value should the engine cooling water be maintained?
During UMS rounds at night during a sea passage the duty engineer discovers the main engine lube oil pump starter “chattering” loudly. What is the correct action to be taken?
Switch over to the other pump and inform the CE of the noise immediately. Keep engine room manned.
Keep engine room manned so that the starter can be checked regularly to see if it gets worse.
Switch over to the other pump and leave the starter until the next morning. Continue UMS operation.
In a low pressure auxiliary boiler, what would you consider to be the maximum allowable chloride level?
The main engine is running steady. What is the normal slow down temperature for the main engine thrust bearing segment?
The Total Base Number (TBN) is important as a measure of neutralizing ability of a diesel engine lubricating oil against strong acids formed during combustion. What action should be taken if the results from an oil analysis show that the TBN of the lubricating oil has reduced slightly?
Purify the system oil in a centrifuge.
Freshen up the system by draining of some of the oil and adding a quantity of fresh oil.
Take another lub oil sample and send it for analysis.
Pump the oil to a renovating tank and allow any contaminants to settle out and refill the system with new oil.
After water-washing the turbocharger exhaust side, the blower starts to vibrate. What has happened?
The rotor blades are damaged or the blades are not properly cleaned.
Water drain for washing system is clogged.
Inlet filter partly clogged.
Foundation bolts for the blower unit are loose.
A simple level control for a water tank consists of a horizontal lever with a float at one end and a filling valve at the other. The lever is provided with an adjustable pivot positioned between the valve and the float. How will the “offset” in the system be affected under changing demand conditions if the pivot is moved closer to the filling valve?
It will reduce the offset on low demand but increase it during high demand.
It will increase the offset on high demand but reduce it on low demand.
It will reduce the offset throughout the demand range.
It will increase the offset across the demand range.
What is generally considered as the minimum safe time period before opening a crankcase door after the oil mist detector alarm has activated and the engine has been stopped?
After at least 20 minutes.
After at least 10 minutes.
After at least 5 minutes.
What is a system employing a single common freshwater cooler (cooled by means of seawater) called?
High temperature freshwater system.
Low temperature freshwater system.
A mechanical seal, consisting of carbon and ceramic seal rings, is to be fitted to a centrifugal pump shaft. What is the most likely result of not being extremely careful when fitting this type of seal?
The seal rings are brittle and can be easily chipped or damaged.
The rubber O rings for the seal can be easily damaged.
The springs and bellows for the seal can be easily damaged.
The seal rings are hard and may score the pump shaft.
Why use a central cooling system?
It is not a complicated system.
It is more easy to operate.
It requires less maintenance.
What refrigerant temperature would you expect at the freon compressor discharge of a cascade system?
Which symptoms would indicate piston blow-by when operating a 4 stroke trunk piston type engine?
Increased pressure in the crankcase and smoke at the crankcase vent.
Increased pressure in the air inlet manifold.
Smoke and sparks from the scavenge manifold drains.
Increased temperature in the inlet air manifold on the engine.
With reference to engine room operations, what does the term “Stand By” mean?
The engineers should be ready to respond to bridge requirements.
Someone should stand close to the watch-keeping engineer.
One should continue with ones work.
Someone is relieved of his duties.
Which of the following options is the most likely to result in the maximum cylinder pressure for all cylinders on a diesel engine to be lower than normal?
Camshaft timing advanced.
Chemical boiling out is one method that is used for cleaning the waterside of a steam boiler. Select from the given options the likely circumstances under which this procedure would be considered necessary?
Excess chloride levels in the boiler water.
Contamination of the boiler water by oil.
Excessive sludge build up in the water drum.
Oxygen pitting in the steam drum.
What will happen if the charge air pressure drops?
The performance of the engine is nearly the same.
The cylinder cooling water flow becomes too high.
The performance of the engine is reduced noticeably.
The turbochargers cooling water flow becomes to high.
What is the main difference between a stuffing box gland and a mechanical seal on a centrifugal pump?
Packed stuffing box glands must be cooled by liquid, but mechanical seals do not require any cooling.
Packed stuffing box glands are subject to wear but mechanical seals are not.
If packing fails the pump can be kept running by tightening the glands, but if a mechanical seal fails it must be renewed to stop the leakage.
The sealing surface of a mechanical seal is usually parallel to the shaft, but sealing surface of a packed gland is perpendicular to the shaft.
What is the main precaution to be taken prior to engaging the turning gear for a diesel engine?
Isolate the starting air supply.
Open the indicator cocks.
Transfer main engine control from control room to emergency control console.
Open the crankcase doors.
A vapour compression refrigeration system is usually fitted with a number of devices to give protection and control of the system. Which of the methods given in the options should be used to test the high pressure cut out during routine maintenance and checking of the system?
Gradually shut in the condenser cooling water valve or the condenser refrigerant inlet valve while closely monitoring the compressor discharge pressure.
Close the condenser outlet valve and closely monitor the condenser pressure.
Manually close each of the evaporator coils by switching off the electrical supply to the liquid line solenoid shut off valves and monitor the condenser pressure.
Why is it necessary to use the vacuum pump after major overhaul of the reefer system?
To evacuate air and water out of the system in order to prevent problem during operation.
In order to reduce the pressure in the system before start-up.
To make underpressure in the reefer system in order to get the freon liquid easy back to the system.
Which of the following fluids usually has the lowest density at normal ambient temperatures?
During inspection of a medium speed diesel engine main bearing the shell is found to have approximately 15 % of the white metal overlay worn away and some light score marks on the exposed aluminium tin bearing metal. Select the most appropriate action to take from the given options?
Refit the shell as it is, this is an acceptable condition for a thin shell bearing after a period of service.
Use a scraper to remove the score marks from the bearing metal before refitting the shell.
Use a scraper to remove the remaining overlay before refitting the shell.
Discard the damaged shell and polish the journal pin before fitting a new shell.
The exhaust temperature in a 4 stroke diesel engine is:
Decreasing if we lower the temperature of the fuel oil.
Falling when a exhaust valve (outlet) is leaking.
Normally lower than in a 2 stroke engine with equal load.
Increasing with poorer cooling of the air in the air cooler.
Which of the following pumps will be damaged if the discharge valve is closed before the motor is stopped?
Read this text and answer the question. “It is recommended that every prospective seafarer should, before being employed in a sea-going ship, receive proper training in personal survival techniques. In respect of such training general recommendations are made”. To whom should training in personal survival techniques be given?
What is the main problem associated with oil in a steam boiler water system?
It forms an insulating film on heat transfer surfaces with the risk of overheating.
It causes corrosion of steel in the boiler.
It causes the gauge glasses to become dirty preventing the operator from seeing the water level.
It increases scale deposits in the boiler.
Which of the options represents the best action to take when an item of machinery, which normally operates in automatic mode, is operated in “manual” mode?
Change over all other machinery to manual mode of operation.
Keep the Chief Engineer informed of machines performance on an hourly basis.
Monitor the operation of the machinery on a frequent basis.
Have someone permanently permanently stationed at the machine in case of an operational problem.