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MAJ EOOW Engineer Exam practice questions

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Question 1Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During routine operation of a two-stroke slow-speed main engine, the scavenge air receiver pressure gauge reads persistently low while the turbocharger speed remains normal. Which immediate check is most appropriate before any adjustment is made?

  1. Verify the scavenge air pressure gauge against a known reference and check for leaking air cooler or receiver joints Correct answer.
  2. Reduce the cylinder lubricator feed rate to lower scavenge space contamination
  3. Open the starting air supply to the air cooler to boost receiver pressure
  4. Increase the fuel index to compensate for the low scavenge pressure

Explanation

A low scavenge pressure reading with normal turbocharger speed suggests either a genuine air leak downstream of the blower or an instrument error, so the reading must be validated and leakage points inspected before any operational change. Adjusting fuel or lubrication based on a possibly false reading risks overloading or damaging the engine.

Question 2Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which component in a slow-speed two-stroke diesel engine is directly responsible for admitting scavenge air and retaining it until exhaust blowdown begins?

  1. Scavenge ports in the cylinder liner Correct answer.
  2. Exhaust valve
  3. Fuel injection pump
  4. Camshaft-driven starting air valve

Explanation

In uniflow-scavenged two-stroke engines the scavenge air enters through ports in the lower cylinder liner, which are uncovered by the piston near bottom dead centre and closed again as the piston rises. These ports therefore control both admission and retention of the scavenge charge.

Question 3Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A medium-speed auxiliary engine shows a gradual rise in exhaust gas temperature on one cylinder with normal cooling water outlet temperature and normal fuel rack position. Which fault is the most probable cause?

  1. Low starting air receiver pressure
  2. Partially seized or sticking fuel injector needle Correct answer.
  3. Worn main bearing shells
  4. Leaking cylinder head gasket allowing coolant into the cylinder

Explanation

A sticking or partially seized injector needle disturbs atomisation and combustion, raising exhaust temperature on that cylinder while the rack position remains normal. Coolant leakage would typically show other symptoms such as water in the sump or pressure fluctuation, and bearing wear or starting air pressure would not be cylinder-specific.

Question 4Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the primary function of the air cooler (charge air cooler) fitted between the turbocharger compressor and the scavenge air receiver?

  1. To preheat the air so ignition delay is shortened
  2. To increase the density of the charge air by reducing its temperature Correct answer.
  3. To reduce the turbocharger shaft speed at high load
  4. To remove moisture from the fuel oil before injection

Explanation

Compressing air in the turbocharger raises its temperature; cooling it after compression increases its density, so a greater mass of air is trapped in the cylinder for combustion. This raises the achievable scavenge pressure and engine output for a given cylinder volume.

Question 5Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

The main engine fails to start on air although the starting air receiver is at normal pressure and the turning gear is disengaged. Which interlock is the most likely cause?

  1. The fuel oil booster pump is stopped
  2. The cylinder lubricator alarm is active
  3. The overspeed trip has not been reset Correct answer.
  4. The jacket cooling water temperature is low

Explanation

An unreset overspeed trip blocks the starting air supply to the manoeuvring system, so the engine cannot be turned on air even with a full receiver. The trip must be acknowledged and reset before starting is permitted.

Question 6Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During a crash astern manoeuvre, why must the engine be brought to a controlled stop before the reversing sequence is completed on a directly reversible slow-speed engine?

  1. To permit the cylinder lubricators to be refilled
  2. To allow the camshaft to be shifted while the engine is stationary, avoiding damage to reversing gear Correct answer.
  3. To allow the turbocharger to cool before reverse running
  4. To allow the fuel rack to be locked in the full position

Explanation

On directly reversible engines the camshaft or fuel pump timing must be repositioned for the opposite direction of rotation, and this is done with the engine stopped or turning very slowly. Attempting to shift while the engine rotates at speed can damage the reversing mechanism.

Question 7Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A slow-speed main engine has been running for two hours when the piston cooling oil outlet temperature on one unit rises steadily above normal. Which action is the most appropriate first response?

  1. Reduce the cylinder lubricator feed rate
  2. Investigate the piston cooling oil flow and temperature for that unit Correct answer.
  3. Stop the turbocharger and inspect the bearings
  4. Increase the engine load to clear the passage

Explanation

A rising piston cooling oil outlet temperature on a single unit indicates reduced cooling oil flow, such as a partially blocked telescopic pipe or passage, or increased heat input from the piston. Investigating that unit's cooling circuit is the correct first step before any load change.

Question 8Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement correctly describes the purpose of the crankcase oil mist detector on a diesel engine?

  1. It measures the viscosity of the lubricating oil in the sump
  2. It controls the fuel rack position during manoeuvring
  3. It monitors the pressure of the starting air supply
  4. It detects a rise in oil mist concentration that indicates an overheating bearing or hot spot Correct answer.

Explanation

A hot spot such as an overheating bearing or piston can vaporise oil and produce a mist in the crankcase, which is an explosion hazard. The oil mist detector senses the increased mist density and alarms or trips the engine to prevent crankcase explosion.

Question 9Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

The main engine governor is set to constant speed but the engine shows hunting at steady load. Which fault is the most likely cause?

  1. Excessive governor droop setting combined with worn linkage Correct answer.
  2. Low starting air pressure
  3. A blocked charge air cooler on one bank
  4. Air trapped in the fuel injection system

Explanation

Hunting at steady load usually stems from excessive proportional or droop action, worn or loose governor-to-fuel-rack linkage, or air in the hydraulic governor system. The combination of excessive droop and worn linkage produces the cyclic over-correction seen as hunting.

Question 10Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the main reason for maintaining a minimum jacket cooling water outlet temperature on a running diesel engine?

  1. To reduce the scavenge air pressure
  2. To keep the lubricating oil viscosity low
  3. To increase the specific fuel consumption
  4. To prevent condensation and corrosive attack on cylinder liners and to limit thermal stress Correct answer.

Explanation

If jacket water temperature is too low, cylinder liner surfaces fall below the dew point of the combustion products, allowing acid condensation and cold corrosion. Maintaining the correct outlet temperature also limits thermal stress across the liner and head.

Question 11Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During a sea passage the fuel oil viscosity at the engine inlet falls below the manufacturer's minimum. Which consequence is most likely if the engine continues at full load?

  1. Improved atomisation with no adverse effect
  2. Excessive injection pump leakage and poor combustion due to low viscosity Correct answer.
  3. Turbocharger overspeed due to higher exhaust energy
  4. Increased cylinder liner corrosion from acid condensation

Explanation

Heavy fuel oil must be heated to a viscosity range that gives correct atomisation and lubrication of the injection pump plungers. If viscosity is too low, internal leakage past the plungers increases, injection timing and quantity become erratic, and combustion quality deteriorates.

Question 12Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which operational check confirms that the fuel injection timing on a slow-speed engine is correct after a fuel pump overhaul?

  1. Verifying the starting air pressure at the manoeuvring valve
  2. Recording the exhaust gas temperature at the turbocharger inlet
  3. Measuring the fuel pump index at full load
  4. Checking the pump timing mark against the camshaft position and observing the injection point on the indicator diagram Correct answer.

Explanation

Injection timing is verified by aligning the pump timing marks with the camshaft datum and confirming the actual start of injection, often using a pressure indicator or timing device. The indicator diagram also shows whether combustion begins at the intended point.

Question 13Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A four-stroke auxiliary engine shows blue-white smoke from the exhaust at normal load. Which cause is most consistent with this symptom?

  1. Correct combustion with high excess air
  2. Too high a fuel injection pressure
  3. Overcooled charge air
  4. Excessive cylinder lubricating oil passing the piston rings Correct answer.

Explanation

Blue-white smoke at normal load typically indicates lubricating oil entering the combustion space, for example from worn rings, valve guides or turbocharger seals. The oil burns incompletely and produces the characteristic haze.

Question 14Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the function of the cylinder relief valve fitted to each cylinder head of a large diesel engine?

  1. To supply starting air to the cylinder
  2. To drain condensate from the scavenge space
  3. To limit peak cylinder pressure by venting to atmosphere if it exceeds a set value Correct answer.
  4. To release excess fuel back to the service tank

Explanation

The cylinder relief valve protects the engine structure from dangerously high peak pressures, for example from liquid slugging or over-fuelling, by lifting and venting combustion gases to atmosphere. It is set above normal firing pressure.

Question 15Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

The turning gear interlock on a main engine is designed to prevent which unsafe condition?

  1. Operating the fuel booster pump without fuel
  2. Starting the engine while the turning gear is still engaged Correct answer.
  3. Opening the scavenge space during running
  4. Running the engine above rated speed

Explanation

If the engine were started on air while the turning gear remained engaged, the gear and flywheel teeth could be severely damaged and personnel could be injured. The interlock blocks starting air until the turning gear is disengaged.

Question 16Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During a blackout recovery on a vessel with a medium-speed main engine, the engine must be restarted from cold. Which sequence is correct for a safe restart?

  1. Pre-lubricate, preheat and turn the engine on air before admitting fuel at low load Correct answer.
  2. Disable the overspeed trip to allow rapid acceleration
  3. Start the engine at full load immediately to restore electrical power
  4. Open the indicator cocks and admit fuel immediately

Explanation

A cold engine should be pre-lubricated to establish oil pressure, preheated where possible, and turned on air to confirm free rotation before fuel is admitted. The engine is then loaded gradually to avoid thermal shock and excessive wear.

Question 17Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which parameter is the most direct indicator of the mechanical condition of a turbocharger bearing during routine operation?

  1. Turbocharger vibration level and bearing oil outlet temperature Correct answer.
  2. Charge air cooler outlet temperature
  3. Jacket cooling water outlet temperature
  4. Scavenge air receiver pressure alone

Explanation

Bearing degradation shows up as increased vibration and a rise in the bearing lubricating oil outlet temperature. Monitoring these trends allows the bearing condition to be assessed before catastrophic failure occurs.

Question 18Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

On a slow-speed engine, the exhaust valve is observed to close late and the valve spindle shows overheating. Which cause is most probable?

  1. Low cylinder lubricator feed rate
  2. Blocked scavenge space drains
  3. Worn air spring sealing rings or a weak air spring supply Correct answer.
  4. Excessively high fuel injection pressure

Explanation

Exhaust valves on large engines are often closed by an air spring, and worn sealing rings or low air spring pressure allow the valve to close late or bounce. Late closing exposes the valve to hot gases and causes overheating and burning.

Question 19Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A main engine indicator diagram shows a reduced maximum firing pressure and a delayed pressure rise on one unit, with normal scavenge pressure. Which fault best explains this?

  1. A leaking exhaust valve
  2. High starting air pressure
  3. A worn fuel injection pump plunger or delayed injection timing Correct answer.
  4. Low jacket cooling water temperature

Explanation

A worn pump plunger or retarded injection timing reduces the quantity and advances the timing of fuel delivered, lowering peak pressure and delaying combustion. Scavenge pressure remains normal because the air supply is unaffected.

Question 20Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the purpose of the scavenge space drain valves on a slow-speed two-stroke engine?

  1. To release combustion gases to the funnel
  2. To drain accumulated oil and water from the scavenge air receiver and prevent carry-over into the cylinders Correct answer.
  3. To drain fuel from the injection pumps
  4. To supply additional scavenge air during starting

Explanation

Oil and water can collect in the scavenge space from piston cooling oil leaks, condensate and cylinder lubrication. Regular draining through the drain valves prevents this liquid from being carried into the cylinders, where it could cause hydraulic locking or smoky combustion.

Question 21Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During manoeuvring, the engine repeatedly fails to fire on starting air although it turns freely. Which cause is most likely?

  1. Turning gear is disengaged
  2. Fuel rack is at zero or the fuel booster pump is not running Correct answer.
  3. Governor is set to constant speed
  4. Starting air pressure is too high

Explanation

If the engine turns but does not fire, air is reaching the cylinders but fuel is not being injected in sufficient quantity. This points to the fuel rack remaining at zero or the fuel supply system, such as the booster pump, not being available.

Question 22Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement best explains why slow-speed two-stroke engines use uniflow scavenging?

  1. It removes the requirement for cylinder lubrication
  2. It eliminates the need for a turbocharger
  3. It allows the scavenge air to flow from the ports at the bottom to the exhaust valve at the top, giving efficient displacement of burnt gases Correct answer.
  4. It permits the use of a single fuel injection pump for all cylinders

Explanation

In uniflow scavenging, air enters through liner ports at the lower end and sweeps upward toward the exhaust valve in the head, giving a controlled flow path and efficient removal of residual gases. This improves scavenging efficiency and combustion quality.

Question 23Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A high exhaust gas temperature alarm on one cylinder of a slow-speed engine is accompanied by a high piston cooling oil outlet temperature on the same unit. What is the most probable cause?

  1. Excessive starting air pressure
  2. Low fuel oil viscosity at the engine inlet
  3. A cracked piston crown or seized piston rings Correct answer.
  4. A blocked charge air cooler on the opposite bank

Explanation

Simultaneous high exhaust temperature and high piston cooling oil outlet temperature on the same unit suggest that combustion heat is passing through the crown or that ring seizure is increasing friction and heat transfer. Both faults require the unit to be investigated and load reduced.

Question 24Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the correct action if the crankcase oil mist detector alarms on a running main engine?

  1. Reduce speed gradually and investigate without opening crankcase doors Correct answer.
  2. Ignore the alarm if bearing temperatures are normal
  3. Increase engine load to burn off the mist
  4. Open the crankcase doors immediately to ventilate

Explanation

An oil mist alarm indicates a possible hot spot and explosion risk. The engine should be slowed and stopped under control, and the crankcase must not be opened until it has cooled sufficiently to avoid an inrush of air igniting the mist.

Question 25Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which maintenance action is most important for preserving the correct operation of the main engine fuel injection pumps between overhauls?

  1. Disabling the fuel pump timing marks
  2. Increasing the fuel rack setting to compensate for wear
  3. Regularly checking plunger and barrel clearances and fuel oil viscosity at the pump inlet Correct answer.
  4. Running the engine on low-viscosity fuel at all loads

Explanation

Injection pump performance depends on the fine clearance between plunger and barrel and on fuel viscosity being within range so that leakage and lubrication are controlled. Monitoring these keeps injection quantity and timing within specification.

Question 26Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

On a large slow-speed two-stroke main engine, what is the primary function of the air cooler after the turbocharger compressor?

  1. It removes moisture only and has no effect on density.
  2. It raises the scavenge air pressure before the receiver.
  3. It heats the air to improve ignition at low load.
  4. It cools the charge air to increase its density and reduce thermal load on the cylinder. Correct answer.

Explanation

Cooling the compressed charge air increases its density so that more air mass is trapped for combustion, allowing more fuel to be burned and greater power from a given cylinder volume. It also lowers the temperature at the start of compression, which reduces peak firing temperatures and thermal stress on pistons, liners and exhaust valves. Moisture removal is a side effect of cooling, not the purpose.

Question 27Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During routine watchkeeping you notice the main engine fuel oil supply pressure at the engine inlet is steady but the fuel oil temperature at the same point has gradually dropped below the specified viscosity-control value. Which immediate consequence should you expect?

  1. No change, because viscosity is controlled by the injection pump timing.
  2. Increased fuel viscosity, poorer atomisation and higher risk of incomplete combustion. Correct answer.
  3. Automatic increase in injection pressure sufficient to compensate.
  4. Lower viscosity, better atomisation and reduced specific fuel consumption.

Explanation

Fuel viscosity rises as temperature falls, and viscosity directly governs atomisation quality at the injector nozzle. Too-high viscosity gives coarse spray, poor mixing with air, delayed and prolonged combustion, and increased deposit formation. The fuel temperature controller should be checked and the setpoint restored before combustion quality deteriorates.

Question 28Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A slow-speed main engine cylinder has a piston cooling oil outlet temperature noticeably higher than the other units, while the inlet pressure and flow remain normal. Which interpretation is most reasonable while the engine is still running?

  1. The cylinder load is lower than the others, so less heat is transferred.
  2. The outlet thermometer is faulty because flow and pressure are unchanged.
  3. Heat transfer to that piston has increased, for example from a cracked piston crown or restricted internal cooling passages. Correct answer.
  4. The affected unit is receiving too much cooling oil and is over-cooled.

Explanation

A rise in outlet temperature with unchanged inlet pressure and flow means the oil is absorbing more heat, not that supply has changed. Typical causes are a cracked or burnt piston crown, blocked internal cooling passages, or abnormally high firing load on that unit. The unit should be monitored, load reduced if necessary, and investigated at the first safe opportunity.

Question 29Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement best describes the purpose of the starting air distributor on a large direct-reversing slow-speed diesel engine?

  1. It times and directs starting air to each cylinder in the correct firing sequence and direction of rotation. Correct answer.
  2. It supplies control air to the governor for speed regulation.
  3. It regulates the pressure of air supplied to the fuel injectors.
  4. It stores sufficient air to complete several consecutive starting attempts.

Explanation

The distributor is a camshaft-driven valve block that admits starting air to the appropriate cylinder air-start valve at the correct crank angle for the selected direction of rotation. Reversing the engine requires the distributor to shift its timing so that cylinders receive air on the correct side of top dead centre for the new direction. Stored air is held in the receivers, not in the distributor.

Question 30Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

The crankcase oil mist detector on a main engine has just alarmed at a rising trend during a sea passage. Which action sequence is correct?

  1. Reduce speed to idle, open the crankcase doors to ventilate, then continue.
  2. Slow the engine, inform the bridge and engine room, and investigate the cause before resuming full load. Correct answer.
  3. Ignore the alarm if the crankcase temperature remains normal.
  4. Stop the engine immediately, then restart it to confirm whether the alarm repeats.

Explanation

A rising oil mist trend indicates possible overheating of bearings or other hot spots that could lead to a crankcase explosion. The correct response is to reduce load, notify the bridge and duty engineer, and investigate the cause through inspection of bearing temperatures and the alarmed unit before restoring full power. Opening crankcase doors while hot risks an inrush of air and an explosion.

Question 31Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

On a slow-speed two-stroke engine, which condition is most likely to cause the scavenge air receiver pressure to fall while the engine runs at constant load?

  1. A sticking cylinder relief valve.
  2. A worn fuel injection pump plunger.
  3. A fouled turbocharger turbine or a leaking air cooler. Correct answer.
  4. A high fuel oil viscosity at the engine inlet.

Explanation

Scavenge receiver pressure is produced by the turbocharger and depends on the pressure ratio it can deliver and on the integrity of the air cooler and ducting. Turbine fouling reduces turbocharger speed and delivery, and an air cooler leak or bypass allows charge air to escape or reduces cooling effectiveness. Fuel-side faults affect combustion but do not directly reduce the air delivery pressure.

Question 32Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement correctly explains why a slow-speed two-stroke engine uses a uniflow scavenge arrangement with exhaust valves in the cylinder head?

  1. It produces a loop of air across the cylinder to cool the piston crown.
  2. It permits the engine to run without a turbocharger at all loads.
  3. It gives a straight flow of air from the scavenge ports to the exhaust valve, improving scavenge efficiency and reducing mixing of fresh air with exhaust gas. Correct answer.
  4. It allows the exhaust valve to be dispensed with on some units.

Explanation

In uniflow scavenging, air enters through ports at the lower part of the liner and sweeps upward in one direction to the exhaust valve in the head. This straight path displaces residual gas efficiently, giving good scavenge quality and low specific fuel consumption. The exhaust valve remains essential to the arrangement.

Question 33Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During manoeuvring, the main engine turns freely on starting air but does not fire on any unit, and the fuel lever position is confirmed as correct for starting. Which cause is most likely?

  1. The starting air pressure is too low to turn the engine.
  2. The cylinder relief valves are lifting.
  3. The fuel oil supply to the engine is shut off or the fuel pump index is at zero. Correct answer.
  4. The turning gear is still engaged.

Explanation

If the engine turns freely on air but does not fire, the fault lies on the fuel side or with the combustion conditions rather than the starting air system. A closed fuel supply valve or a fuel pump index at zero would prevent injection on all units, matching the symptom. Air pressure, turning gear interlock and relief valves all affect turning or protection, not firing on all units.

Question 34Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement best describes the function of the cylinder lubricator on a crosshead-type slow-speed diesel engine?

  1. It lubricates the turbocharger bearings during operation.
  2. It supplies oil to the crankcase for main bearing lubrication.
  3. It meters small quantities of alkaline cylinder oil to the liner at each stroke to neutralise acids and control wear. Correct answer.
  4. It circulates oil through the piston cooling system.

Explanation

In a crosshead engine the cylinder and crankcase are separated, so the liner relies on a dedicated cylinder lubricator. Small, accurately metered quantities of oil are injected through quills to the liner surface to provide boundary lubrication and neutralise the acidic products of heavy fuel combustion. Crankcase and turbocharger lubrication are handled by separate systems.

Question 35Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

A slow-speed main engine has a high exhaust gas temperature on one unit together with a high piston cooling oil outlet temperature on the same unit, while scavenge air pressure and fuel rack position are normal. Which cause best fits this combination?

  1. Low cylinder oil feed rate on that unit.
  2. Overload of that cylinder from excessive fuel injection on that unit. Correct answer.
  3. A leaking exhaust valve passing hot gas into the scavenge space.
  4. A partially blocked air cooler on the common air system.

Explanation

High exhaust temperature and high piston cooling outlet temperature on one unit, with normal air supply, point to excessive heat release in that cylinder. Over-fuelling through an incorrectly set or sticking fuel pump raises firing pressure and heat transfer to the piston and exhaust. A common air-side fault would affect all units, not one.

Question 36Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which operational check best confirms that the fuel injection timing on a slow-speed diesel engine is correct after a fuel pump overhaul?

  1. Confirming the pump timing mark aligns with the camshaft timing mark and that the injector opens at the specified pressure. Correct answer.
  2. Comparing the fuel rack position with the other units.
  3. Observing the colour of the exhaust gas at full load.
  4. Checking the pump barrel temperature after running.

Explanation

Injection timing is set mechanically by the relationship between the fuel cam and the pump, so the timing marks must be verified after reassembly. The injector opening pressure must also be within specification because it affects when injection actually begins. Exhaust colour and rack position are indirect indicators only.

Question 37Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

What is the primary purpose of the scavenge space drain valves on a slow-speed two-stroke engine?

  1. To drain cooling water from the cylinder jackets.
  2. To admit extra air during high-load operation.
  3. To relieve excessive scavenge air pressure to atmosphere.
  4. To drain accumulated oil and water from the scavenge space so it cannot be carried into the cylinders. Correct answer.

Explanation

Oil and water can collect in the scavenge space from piston cooling leaks, cylinder oil, or condensation. If this collects, it can be drawn into the cylinders on the next scavenge period, causing hydraulic loading or fouling. Regular draining and inspection of the drain indicates leakage problems and protects the running gear.

Question 38Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

During a routine inspection you find the main engine crankcase oil level is above the upper mark and the oil is milky. Which combination of causes best explains these findings?

  1. Normal oil consumption being compensated by topping up.
  2. Fuel dilution from a leaking fuel pump plunger only.
  3. Water ingress into the crankcase from a leaking cooler or jacket, combined with overfilling. Correct answer.
  4. Excessive oil mist generation due to high crankcase temperature.

Explanation

Milky oil indicates emulsified water, typically from a leaking cooling water system within the engine or a leaking oil cooler. A level above the upper mark suggests overfilling or additional liquid entering the sump. The oil should be tested, the source of water found, and the charge corrected before bearing damage occurs.

Question 39Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which statement correctly describes the purpose of the crankcase breather arrangement on a large diesel engine?

  1. It allows the crankcase to vent gases and maintain a pressure close to atmospheric to avoid seal leakage and mist carry-over. Correct answer.
  2. It maintains a slight positive pressure in the crankcase to keep out contaminants.
  3. It provides cooling air to the alternator.
  4. It supplies air to the turbocharger inlet.

Explanation

Combustion blow-by and oil vapour raise the pressure inside the crankcase, which can force oil past seals and carry mist into the engine room. The breather vents these gases, often through an oil separator, and keeps the crankcase near atmospheric pressure. It does not supply combustion air or pressurise the case.

Question 40Marine Engineering Knowledge - Propulsion Plant and Machinery Operation

Which maintenance practice is most important for preserving the correct operation and long life of main engine fuel injection pumps on a slow-speed diesel engine?

  1. Regularly changing the pump lubricating oil without checking the fuel condition.
  2. Maintaining fuel oil cleanliness and viscosity, and checking pump timing and plunger/barrel wear at recommended intervals. Correct answer.
  3. Running the engine on heavy fuel at low temperature to protect the plungers.
  4. Periodically increasing the pump delivery pressure beyond the specified value.

Explanation

Injection pumps are precision assemblies with closely matched plungers and barrels; abrasive particles in the fuel cause rapid wear and loss of delivery. Correct viscosity ensures proper lubrication and atomisation, and periodic checks of timing and clearances detect wear before it becomes a failure. These measures address the actual wear mechanisms.

Question 41Engine Room Watchkeeping, Procedures and Record Keeping

During an unmanned machinery space (UMS) period, which alarm classification must be arranged so that it is annunciated to a responsible engineer who can return to the engine room within a reasonable time?

  1. A dead-man alarm
  2. A safety alarm
  3. A machinery alarm Correct answer.
  4. A general emergency alarm

Explanation

In UMS operation, alarms are graded. Machinery alarms indicate a parameter drifting from normal and are extended to a duty engineer who must attend; safety alarms shut down or protect the plant and are also extended, while a dead-man alarm monitors the watchkeeper's own alertness. The distinction determines who is called and how urgently.

Question 42Engine Room Watchkeeping, Procedures and Record Keeping

The engineer on watch notices the main engine fuel oil viscosity at the injection pumps falling below the manufacturer's minimum. What is the immediate correct watchkeeping action?

  1. Stop the fuel booster pump to prevent further heating
  2. Record the reading and check again at the end of the watch
  3. Increase the fuel oil heater outlet temperature setting
  4. Reduce the fuel oil heater output and verify the viscosity controller is responding Correct answer.

Explanation

Low viscosity means the fuel is too hot or too light, which reduces lubricity and can cause injection pump wear and poor combustion. The watchkeeper must correct the heat input and confirm the viscosity controller is actually modulating, then monitor the trend. Simply logging the value defers a developing defect.

Question 43Engine Room Watchkeeping, Procedures and Record Keeping

Under the STCW rest-hour requirements, what is the minimum continuous rest period that a watchkeeping engineer must receive in any 24-hour period?

  1. 4 hours
  2. 8 hours
  3. 10 hours
  4. 6 hours Correct answer.

Explanation

STCW sets minimum rest of 10 hours in any 24-hour period and 77 hours in any 7-day period, but the 10 hours may be divided into no more than two periods, one of which must be at least 6 hours continuous. The 6-hour continuous block is the protection against fragmented rest.

Question 44Engine Room Watchkeeping, Procedures and Record Keeping

The oily water separator is required to be tested and its 15 ppm alarm verified. Which record entry best demonstrates compliance to a port State control inspector?

  1. The oil record book entry for the last transfer of bilge water
  2. The maker's instruction manual page reference for the separator
  3. A note in the engine room logbook that the separator 'works fine'
  4. The date, time, method of test and the signature of the officer who verified the 15 ppm alarm and automatic stopping device Correct answer.

Explanation

MARPOL requires the oily water separator's alarm and automatic stopping arrangement to be verified before discharge and periodically. The defensible record identifies when, how and by whom the function was proven, because that shows the equipment was actually tested rather than merely present. Vague or indirect entries do not evidence a functional test.

Question 45Engine Room Watchkeeping, Procedures and Record Keeping

During a machinery space round, the watchkeeper finds the bilge level in the main engine drip tray rising and the bilge high-level alarm has not operated. What is the correct first action?

  1. Open the sea suction to the bilge system and dilute the tray contents
  2. Investigate the source of the leakage and pump the tray bilge Correct answer.
  3. Wait for the next round to see whether the level stabilises
  4. Disconnect the alarm sensor to prevent a nuisance alarm

Explanation

A rising bilge with a failed high-level alarm indicates both a leakage and an alarm defect, so the watchkeeper must find the source and control the accumulation before it reaches machinery or tank tops. Diluting or disabling protective devices conceals the defect and breaches pollution prevention requirements.

Question 46Engine Room Watchkeeping, Procedures and Record Keeping

Which of the following is the correct sequence when handing over the engine room watch to the relieving engineer?

  1. The outgoing engineer leaves after briefing, and the relieving engineer begins the round afterwards
  2. The relieving engineer signs the logbook before the outgoing engineer completes the round
  3. Both engineers conduct a joint round, review standing orders and outstanding defects, then the relieving engineer formally accepts the watch Correct answer.
  4. The relieving engineer accepts the watch by radio from the accommodation and checks the plant later

Explanation

A proper handover requires a joint inspection of the running plant, a briefing on defects, ongoing work, permits and standing orders, and an explicit acceptance of responsibility. Responsibility passes only at the point of formal acceptance, so the relieving engineer must be satisfied before signing.

Question 47Engine Room Watchkeeping, Procedures and Record Keeping

A permit to work has been issued for entry into a main engine scavenge air receiver. Which condition must be confirmed before the permit is signed as valid?

  1. The engine is running slowly so that the space remains ventilated
  2. A second person is available to hand tools through the entry opening
  3. The receiver has been isolated, depressurised, locked out and proved gas-free with a calibrated instrument Correct answer.
  4. The duty engineer has verbally informed the bridge that entry will take place

Explanation

Enclosed space entry requires positive isolation of all energy and fluid sources, physical lock-out, and verification of a safe atmosphere with a calibrated instrument before the permit is validated. Verbal notification or a running engine does not create a safe, isolated space.

Question 48Engine Room Watchkeeping, Procedures and Record Keeping

The engine room logbook shows that the main engine was run at reduced load for six hours because of a high exhaust gas temperature on one unit. What is the principal reason for recording this in the logbook and the chief engineer's record?

  1. To provide a chronological, defensible record of the plant condition and the action taken for later diagnosis and inspection Correct answer.
  2. To show that the watchkeeper was present in the engine room
  3. To satisfy the charterer's fuel consumption claim
  4. To calculate the overtime payable to the engine room ratings

Explanation

The logbook is a legal and technical record. A dated entry naming the abnormal parameter, the action taken and the outcome allows trends to be diagnosed, supports maintenance planning and protects the crew if the event is later questioned. Its purpose is not commercial or administrative.

Question 49Engine Room Watchkeeping, Procedures and Record Keeping

During manoeuvring, the bridge orders 'dead slow ahead' and then 'stop'. Which engine room action correctly supports this period?

  1. The watchkeeper keeps the engine room manned, stands by the manoeuvring controls and confirms each telegraph order is executed Correct answer.
  2. The watchkeeper leaves the controls to complete the noon logbook entries
  3. The watchkeeper transfers control to the bridge and leaves the engine room
  4. The watchkeeper starts the standby generator and shuts down the main switchboard alarms

Explanation

Standby and manoeuvring are critical periods when the engine room must be manned and the controls attended, with each telegraph order acknowledged and executed promptly. Control must not be left unattended and paperwork waits until the manoeuvre is over.

Question 50Engine Room Watchkeeping, Procedures and Record Keeping

The main engine lubricating oil mist detector alarm activates. What is the correct watchkeeping response?

  1. Reduce load, inform the bridge and chief engineer, and investigate the affected unit before restoring normal operation Correct answer.
  2. Stop the lubricating oil pump to interrupt the mist generation
  3. Increase crankcase ventilation to clear the mist
  4. Reset the alarm and continue at full load

Explanation

Oil mist indicates a hot spot such as a bearing or piston seizure and is a precursor to crankcase explosion. The watchkeeper must reduce load to limit heat generation, inform the bridge and chief engineer, and identify the affected unit before resuming. Resetting or forcing ventilation masks the hazard.