Le test comprend 80 questions aléatoires.
Total de questions sur ce sujet : 147
Modern slow speed, two stroke diesel engines often have locating pins or pegs to keep the piston rings in a fixed position. Why is this arrangement used?
The piston ring gaps can be kept in line to control the gas pressure on each of the rings.
The piston rings are more difficult to lubricate because of the slow operating speeds and will wear more quickly if they are allowed to rotate.
It avoids the risk of the ends of the piston rings being forced out by the gas pressure and catching on the scavenge ports.
It ensures the rings cannot be mixed up and that they are fitted in the correct order on the piston.
What do you understand by: “Let go the port anchor?”
Let go the port anchor means: slacken the port anchor cable.
Let go the port anchor means: put the port windlass brake in gear.
Let go the port anchor means: put the port windlass brake in gear and lower the anchor.
Let go the port anchor means: open the port windlass brake.
Which of the following is not a principle of heat transfer utilised in an oil fired steam boiler?
A piston rod retaining nut needs to be tightened during maintenance on the main engine. Which of the given methods should be used to ensure it does not come loose in service?
Tighten it as tight as possible using a flogging spanner and a hammer.
Tighten it 10 % more than the manufacturer’s recommendation using a torque wrench.
Tighten it to the manufacturer’s recommendations using a torque wrench.
Tighten it as tight as possible using a spanner and extension pipe.
What could be the cause of a refrigeration compressor running continuously even though normal temperatures for the cold rooms have been reached?
Solenoid valve before the expansion valve stuck in closed position.
High-pressure cut-out is stuck in open position.
The differential pressure switch for the lubricating oil pressure cut-out is stuck in the closed position.
Low-pressure cut-out is stuck in closed position.
The packed gland on a centrifugal pump is leaking even though the gland has been “nipped up”. What is the correct action to take to stop the leakage?
Tighten up the gland as much as possible until the leakage stops.
Ensure the bilge well to which the leakage is draining is regularly pumped out.
Re-pack the stuffing box loosely with the correct size packing at the earliest opportunity.
Fit an extra ring of oversize packing to the stuffing box at the earliest opportunity.
What is the correct name of the tool shown in the illustration?
A ship moving through heavy seas is affected by the water presure at the bows causing an effect known as “Panting”. What structure in the forward region of the ship combats the effects of Panting?
Double bottom tanks and floors.
Panting beams and stringers.
Collision bulkhead and deck.
Which of the following instruments is normally part of a control-loop?
What is the correct name of the part highlighted in the illustration?
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 hard and may score the pump shaft.
The spring and bellows for the seal can be easily damaged.
The seal rings are brittle and can be easily chipped or damaged.
The rubber O rings for the seal can be easily damaged.
Modern slow speed, two stroke diesel engines often have locating pins or pegs to keep the piston rings in a fixed position. Why is this arrangement used?
The piston ring gaps can be kept in line to control the gas pressure on each of the rings.
The piston rings are more difficult to lubricate because of the slow operating speeds and will wear more quickly if they are allowed to rotate.
It avoids the risk of the ends of the piston rings being forced out by the gas pressure and catching on the scavenge ports.
It ensures the rings cannot be mixed up and that they are fitted in the correct order on the piston.
The responsibility for safety and security rests with everybody on board the vessel. General house-keeping rules should be followed. Which of the listed rules is the most important?
Do not carry lighters or matches when working outdoors.
Always use gloves when using grinding machines.
Keep tools within easy reach during work.
Keep your working area clean and tidy.
Is it necessary to cool the samples taken from a diesel engine cooling water system before carrying out tests to determine the concentration of treatment chemicals?
No, the test should be carried out at system temperature.
Yes, the samples should be cooled to approximately 25 °C.
Yes, the samples should be cooled to approximately 50 °C.
No, the samples should be heated to approximately 95 °C.
What will be the probable outcome if the amplification is set too high on a controller?
The process will oscillate and get out of control.
The set-point will change.
The process response will be very slow.
If a refrigeration system contains air, how would you remove it from the system?
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.
Stop the compressor and vent the air from the crankcase.
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 undo a pipe coupling at the highest point in the system to vent off the air.
B Class divisions in ships are constructed so that they are capable of preventing the passage of flame to the end of a standard fire test held for:
A seawater pump requires overhaul but there are no spare wear rings for the casing and impeller. It is decided that new wear rings will be fabricated onboard using the ship’s lathe. What would be the most suitable material to use to fabricate the rings onboard?
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 several recommendations are made. Answer the question: “To whom should training in personal survival techniques be given?”
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 small and/or the flow rate is too high.
The throughput is too low.
The gravity is too large.
What is the correct method to use for fitting a rolling contact bearing, such as a ball bearing, onto a parallel shaft?
Use a hammer and a pipe with the same diameter as the inner bearing ring and knock the bearing onto the shaft.
Use emery cloth on the bearing surface on the shaft.
Use emery cloth on the inner ring (contact surface) of the bearing.
Gently heat the bearing in an oil bath and use a bearing puller to draw it onto the shaft.
What is the main effect on lubricating oil of operating for long periods at excessively high temperature?
It will cause the oil to oxiside, increasing the viscosity.
It will cause the oil to oxidise, reducing the viscosity.
It will cause the oil to evaporate, increasing consumption.
It will change the flashpoint of the oil.
What is the main reason for keeping engine lubricating oil viscosity within recommended limits?
To reduce system pressure losses.
To ensure the strength of the oil film is sufficient to keep lubricated surfaces apart.
To neutralise any acids that may form.
An electrical power emergency source in a ship is required because:
It satisfies the SOLAS requirements for ship safety.
The main diesel generator(s) can be taken out of service for overhaul or repair.
It satisfies the need to be environmentally “friendly”.
The ships total load can be shared between main and emergency generators.
During maintenance of a pneumatically operated, diaphragm actuated control valve the diaphragm is found to be split. Select, from the options given, a suitable material to use to make a temporary replacement if there is no spare diaphragm available.
Natural rubber sheet of approximately the same thickness and elasticity as the original diaphragm material.
Cotton reinforced rubber insertion sheet of smaller thickness but similar strength as the original diaphragm material.
Natural rubber sheet of greater thickness and lower elasticity as the original diaphragm material.
Cotton reinforced rubber insertion sheet of approximately the same thickness but less elasticity than the original diaphragm material.
What is the correct name of the part highlighted in the illustration?
Which part of the crankshaft of a modern large two stroke diesel engine is most likely to be the origin point for crack initiation during service and therefore needs the greatest attention during maintenance inspection?
The dowel pins and dowel holes.
What does the term “Dead Ship” mean?
“Dead Ship” means that the ship cannot make way through the water.
“Dead Ship” means that the ship is aground.
“Dead Ship” means that the machinery and boilers are inoperational due to lack of electrical power.
“Dead Ship” means that auxiliary machinery is not operational.
What is one of the main features of the cylinder lubricating oil used in large 2 stroke marine diesel engines which normally operate on heavy fuel oil?
It is neutral with a pH value of 7.
It is a pure mineral oil without any special additives.
During an unmanned period on a UMS vessel the “low water level” alarm for the jacket cooling water system expansion tank activates. What action would you take as duty engineer?
Answer the alarm then block the alarm and change to manned engine room condition.
Answer the alarm then block the alarm function for later action and resume unmanned operation.
Answer the alarm and adjust the alarm set point for the water level in the expansion tank before resuming unmanned operation.
Answer the alarm, top up the tank and check the system for leakage before resuming unmanned operation.
What is likely to be the cause of black smoke from a diesel engine exhaust seen at the funnel?
Engine is burning some lubricating oil.
Incomplete combustion of the fuel.
What function is this operational amplifier circuit performing?
The two instruments necessary for generator synchonising are:
kW meter and frequency meter.
Voltmeter and synchroscope.
Synchroscope and kVar-meter.
Amp-meter and volt-meter.
What is the expansion ratio of the foam produced by the fixed low-expansion foam fire-extinguishing system of an engine room?
Greater than 20 to 1 but less than 50 to 1.
For two generators running in parallel, their share of additional load (kW) will be determined by the:
Voltage droop setting on each AVR.
Governor droop settings on each prime mover.
The temperature difference between the generator rotors.
The power factor of the additional load.
As part of the regular maintenance for a paramagnetic oxygen analyser used for measuring the oxygen content of exhaust gas it is important to keep the sample line filter as clean as possible. Why is this necessary with this type of instrument?
The filter may rupture due to the high pressures generated by the sample pump.
Pressure variations in the sample chamber can cause errors so restrictions must be kept to a minimum.
The pressure drop across the filter may damage the sampling pump.
A high flow rate is required in order to deflect the sensing element.
What is the best method to use to remove heavy scale and fouling from the plates of a heat exchanger?
Use high-pressure cleaner with abrasive additives.
Soak the plates in recommended cleaning solution and then use a soft brush or pressure cleaner.
Use wire-brush metal scrapers and chipping guns.
Which one of the listed requirements regarding the stowage of a survival craft corresponds to present SOLAS regulations? Each survival craft shall be stowed:
In a secure and sheltered position and protected from damage by fire or explosion.
Wherever space is available.
In a state of readiness so that two crew-members can prepare for embarkation and launching in less than 15 minutes.
On the starboard side of the ship.
In a diesel engine lubrication system the circulating pump normally takes suction from the oil sump tank. Where would the oil normally pass to directly after the pump?
Which component does this graphical symbol illustrate?
Pressure indicator, installed on panel/console.
Pressure indicator, installed locally.
Pressure relief valve, self-contained.
Many large slow speed diesel engines operating on heavy fuel oil have a fuel injection system which features Variable Injection Timing. How does this affect engine operation?
VIT increases engine efficiency by automatically maintaining the maximum cylinder pressure over the entire load range.
VIT allows the ship’s engineers to alter the injection timing for each load setting with a simple single adjustment of the fuel rack.
VIT increases engine efficiency by automatically maintaining the maximum cylinder pressure over part of the load range.
MARPOL – Annex V. Disposal of garbage outside “Special Areas”. After unpacking spares, you are left with a limited amount of packing materials. Is this prohibited, if not, what will be the nearest distance to land for disposal into the sea of these materials?
New MARPOL regulations came into effect from July 93 stating that the previous instantaneous rate of discharge of oil content (60 litters per nautical mile) was changed to:
10 litters per nautical mile.
25 litters per nautical mile.
30 litters per nautical mile.
20 litters per nautical mile.
You are starting to get low on water in the lifeboat. What should you do?
Mix sea water with 50 % fresh water.
The exhaust gas temperatures of all cylinders of a diesel engine are seen to be high. Select, from the options given, the most likely cause of this:
Insufficient cooling of the main bearings.
High wear rate in one of the fuel injection pumps.
One of the fuel cams is worn.
Is it always possible to use the word “ship” instead of the word “boat”?
A large vessel is always called a “ship” and never a “boat”.
Normally a small vessel is called a “boat” rather than a “ship”, otherwise it is not important.
Either can be used anytime.
A boat can only be used for vessels under 50 metres in length.
During a bomb search, which of the following is an important principle to follow?
Throw any suspicious items overboard.
Try to reach behind bulkheads to find a bomb.
Do not touch any suspicious packages.
Know exactly what a bomb looks like.
Many large 2 stroke marine diesel engines are equipped with an auxiliary scavenge air blower. What is the purpose of this equipment?
To provide combustion air at start up, during manoeuvring and low load running when the turbocharger delivery is insufficient.
To allow full load running when the main turbocharger is defective.
To assist the main turbochargers in supplying combustion air when on full load.
To help cool the engine after it has been stopped.
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 5 minutes.
After at least 10 minutes.
When referring to onboard oil treatments using a centrifuge, what is meant by the term purification?
Separation of solid contaminants from a liquid during the process.
Separation of two insoluble liquids with different densities, and the removal of solids in the same process.
It is a general term applied to a process for cleaning oil using a centrifuge.
Separation of one insoluble liquid from another.
Before leaving the machinery spaces of a UMS vessel after routine watchkeeping rounds in the evening, the duty engineer inspects the doors to Fuel Oil Treatment rooms which are covered by a fixed fire fighting installation. For what purpose does he do this?
To tie them open with a rope to prevent the heat from building up inside, and making it uncomfortable to work.
Remove the auto closing device so they remain in whatever position.
Wedge them open with an arrangement which allows them to be closed quickly in the event of a fire.
To make sure that they are properly closed with the self closing device so that any fire is contained and the extinguishing medium can be released without delay.
Which of the following fittings shall be provided to all lifeboats?
A manually controlled lamp fitted on the outside.
A remotely operated steering arrangement.
An electric power starting system for the propulsion engine with one rechargeable energy source.
Permanent boarding arrangements on both sides to enable persons in the water to board the lifeboat.
Why is it important to check the timing of diesel engine cylinder oil lubricators?
To ensure the piston is not covering the lubrication points and blocking the flow of cylinder lubricating oil into the cylinder.
To ensure the correct amount of cylinder lubricating oil is fed into the cylinders.
To ensure cylinder lubricating oil enters the cylinders when the piston is in the required position.
To avoid excess pressure in the cylinder lubrication system.
What is the meaning of “make fast”?
When a fire breaks out in the accommodation, cargo holds or on deck, who is in charge of the fire fighting operations?
The first officer arriving at the scene.
The first person arriving at the scene.
The person who is designated in the muster list.
In a low pressure auxiliary boiler, what would be considered to be the maximum allowable chloride level of the boiler water?
What is the main advantage of having a central cooling system fitted on board ship?
It should require less maintenance than a conventional system using only sea water.
It is a simple system with minimum control requirements.
It does not require any seawater.
Only one heat exchanger is needed for all cooling duties.
Many large slow speed diesel engines operating on heavy fuel oil have a fuel injection system which features Variable Injection Timing. How does this affect engine operation?
VIT increases engine efficiency by automatically maintaining the maximum cylinder pressure over the entire load range.
VIT increases engine efficiency by automatically maintaining the maximum cylinder pressure over part of the load range.
VIT improves engine operation by automatically controlling the start of fuel injection when it detects a poor quality fuel.
VIT allows the ship’s engineers to alter the injection timing for each load setting with a simple single adjustment of the fuel rack.
PT-100 sensors are some times used with 3 or 4 wires. What is the reason for this?
Higher mechanical strength of the cable.
Because of power-consumption.
Higher measuring accuracy.
A flame detector is activated by:
Smoke, gas, sparks and high temperature.
The radiation of heat given off by flames.
The rise of the environment temperature.
The infrared radiation and ultraviolet radiation given off by flames.
The correct time to synchronise is usually taken to be when the synchroscope reaches the “5 to 12” position and is rotating slowly clockwise. This to allow for:
Generator phase difference error.
Circuit breaker operating time.
Synchroscope pointer time lag.
What is the approximate content of oxygen in air?
An air compressor is being refitted in the engine room. The compressor and motor are coupled using a flexible coupling and are mounted on a common “skid” which fixed to the deck with resilient mountings. Which of the statements, from the options given, relating to the alignment of the motor and compressor is true?
Shims should be fitted between the motor and compressor feet and the skid to ensure correct vertical, horizontal and parallel alignment of the coupling halves before it is bolted up.
As long as the two coupling halves are at the same height the flexible coupling will accommodate any horizontal misalingment of difference in the gap between the coupling faces.
The compressor and motor can just be placed directly on the common skid as they will probably be closely aligned anyway.
Machines using flexible couplings and resilient mountings do not need to be aligned. That is why they have flexible and resilient elements fitted.
A vapour compression refrigiration 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?
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.
Close the condenser outlet valve and closely monitor the condenser pressure.
Gradually shut in the condenser cooling water valve or the condenser refrigerant inlet valve while closely monitoring the compressor discharge pressure.
Charge the system with refrigerant until the high pressure cut out operates.
It is common practice to connect a resistor over an alarm contact (see diagram) in many applications. Why is this connection used?
To monitor the cable/wires for break.
To stabilise power consumption.
To avoid sparks on the contacts when opening and closing.
Enable measuring the total resistance of the circuit.
A detector that is activated by a rise of temperature is:
During maintenance of a piston rod stuffing box on a large, slow speed diesel engine it is usual to measure the butt gaps between the sealing ring and scrapper ring segments. What would be the effect of these gaps being too small?
If the gaps are too small the rings could scope the piston rod.
If the gaps are too small they could close due to the radial wear of the rings before the next scheduled overhaul preventing the rings from contacting the piston rod and sealing it.
If the gaps are too small then the flow of scavenge air through the gland would be reduced and the gland would overheat.
If the gaps were too small then no oil could pass up the piston rod to lubricate the sealing rings.
After main power is restored (following a blackout), a timed sequential restart of motor driven auxiliaries is necessary to avoid:
Generator overload due to many motors starting at simultaneously.
Overvoltage due to current surges.
Overloading creating earth faults.
Over-frequency due to overspeed of generator.
Why may wearing sweat rags slung round your neck when working in the machinery spaces be hazardous?
The rags may cause sweat rash.
The rags may cause you to get too hot and faint.
The rags may be soaked with oil and catch fire.
The rags may be caught by running machinery or power tools.
What effect does an increased oil feed flow rate have on the performance of a centrifuge operating as a purifier?
Separating efficiency is unchanged.
Separating efficiency is increased, more water is removed.
Separating efficiency is increased, more solids are removed.
Separating efficiency is reduced.
What precautions should be taken, in addition to shutting the main air start valve if work is to be carried out inside the main diesel engine crankcase?
Keep a man posted in the control room to stop anyone who tries to start the engine.
Engage the turning gear and put a notice at each engine control position.
Engage the turning gear, stop the starting air compressors and drain the air receivers.
Engage the turning gear and close every valve on the starting air receivers.
Select the option which best describes the primary duty of a watch-keeping engineer:
The primary duty of a watch-keeping engineer is to maintain constant surveillance of the main engine and auxiliary machinery.
The primary duty of a watch-keeping engineer is to maintain the ship’s speed.
The primary duty of a watch-keeping engineer is to ensure that machinery spaces are properly manned.
The primary duty of a watch-keeping engineer is to maintain constant surveillance of the steering gear.
This device can detect a package of drugs inside a large delivery of ship’s stores. What is it?
When you are calibrating an instrument what is the most common second step in the procedure?
Adjustment of Zero-point.
During maintenance work on a compensated mechanical hydraulic governor air is drawn in to the hydraulic circuit after draining and flushing out the unit. Which of the actions given in the options is most likely to assist in the removal of the air from the system?
With the governor in operation open the compensation needle valve to introduce instability and disturb the engine load to make the governor hunt.
Overfill the governor with fresh oil to force all of the air out.
Drain the governor again and slowly refill with fresh oil.
With the governor in operation close the compensation needle valve and disturb the load to make the engine hunt.
A ship has a medium speed engine and a controllable pitch propeller propulsion system. What would the propeller pitch normally have to be at to allow starting of the engine?
What could cause diesel engine lubricating oil to appear cloudy with a slightly “milky” colour?
Fuel contamination of the system.
High temperature of the oil.
Water contamination of the system.
For a Nitrite – Borate based cooling water treatment system, what would be considered to be the normal nitrite concentration limits for a correctly dosed system?
3 000 – 4 500 ppm Nitrite.
1 500 – 3 000 ppm Nitrite.
4 500 – 6 000 ppm Nitrite.
Which diagram is the symbol for a THYRISTOR?
An earth fault exists on the blue line of a 100 A bilge pump circuit. A second earth fault occurs on the yellow line of a 10 A ventilation fan circuit. Both systems are supplied from the ship’s 440 V supply. The likely outcome is that:
A short circuit occurs between earth faults and the ventilation fan fuse blows.
An open circuit occurs between earth fault and both motors trip out.
A short circuit occurs between earth fault and the bilge pump fuse blows.
Both motors trip out on overload.