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Kazakhstan Maritime Engine Officer study materials
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Kazakhstan Maritime Engine Officer practice questions

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Question 1Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a four-stroke marine diesel engine, at which point in the cycle does the fuel injection normally begin?

  1. Immediately after the exhaust valve closes at the start of the intake stroke
  2. Shortly before top dead centre at the end of the compression stroke Correct answer.
  3. At mid-stroke during the power stroke
  4. At bottom dead centre at the start of the compression stroke

Explanation

Fuel is injected near the end of compression, slightly before top dead centre, so that ignition delay and combustion phasing produce peak pressure just after TDC. Injecting earlier or later shifts the pressure curve and reduces efficiency or raises thermal load.

Question 2Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the primary function of the scavenge air receiver on a large two-stroke marine diesel engine?

  1. To cool the exhaust gas before it enters the turbocharger
  2. To separate water from the fuel oil supply
  3. To damp torsional vibration in the crankshaft
  4. To store a volume of pressurised charge air for delivery to the cylinder liner ports Correct answer.

Explanation

The scavenge air receiver acts as a pressure reservoir that smooths pulsations from the turbocharger and supplies a steady flow of charge air to the scavenge ports. Uniform pressure there is essential for effective scavenging and cylinder filling.

Question 3Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A marine auxiliary boiler shows a falling water level in the gauge glass while steam demand and feed pump running are normal. Which immediate action is most appropriate?

  1. Check the feed water control valve and feed pump discharge pressure for a fault Correct answer.
  2. Open the main steam stop valve further to reduce drum pressure
  3. Blow down the boiler to lower the water level
  4. Increase the boiler firing rate to raise steam output

Explanation

A falling level with normal demand points to a feed supply problem, so the feed control valve position and pump discharge pressure should be verified first. Raising firing or blowing down would worsen a low-water condition and risk overheating the tubes.

Question 4Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Which parameter is most commonly used to detect a leaking fuel injector on a large diesel engine?

  1. Exhaust gas temperature of the affected cylinder compared with the others Correct answer.
  2. Scavenge air receiver pressure
  3. Lubricating oil viscosity in the sump
  4. Jacket cooling water pH value

Explanation

A leaking or dribbling injector usually produces abnormal combustion, which shows as a deviating exhaust gas temperature for that cylinder. Comparing individual cylinder temperatures against the average is the standard diagnostic.

Question 5Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the main purpose of the air cooler (charge air cooler) fitted after the turbocharger compressor?

  1. To preheat the fuel oil before injection
  2. To increase the density of the charge air before it enters the cylinders Correct answer.
  3. To remove water vapour from the exhaust gas
  4. To reduce the turbocharger shaft speed

Explanation

Cooling the compressed air increases its density, so a greater mass of air is trapped in the cylinder for the same swept volume, raising the available oxygen for combustion. It also lowers the thermal load on the engine.

Question 6Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a marine diesel engine, what does the term 'torsional vibration damper' primarily protect?

  1. The cylinder liners from abrasive wear
  2. The sea water cooling system from water hammer
  3. The crankshaft and shafting from excessive torsional oscillation Correct answer.
  4. The fuel injection pumps from pressure surges

Explanation

Torsional dampers absorb or detune torsional oscillations that build up in the crankshaft and shafting, keeping stress within safe limits. Without effective damping, fatigue cracking of the shaft can occur.

Question 7Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A centrifugal purifier is used to clean heavy fuel oil. What is the effect of raising the bowl speed above its design value?

  1. The purifier automatically switches to clarifier mode
  2. The sludge discharge interval becomes shorter
  3. Separation efficiency falls because the oil becomes too viscous
  4. Separation efficiency improves but mechanical stress on the bowl increases and may exceed safe limits Correct answer.

Explanation

Higher bowl speed increases the centrifugal force and improves separation, but the bowl is designed for a maximum speed and exceeding it raises stress on the bowl material, risking catastrophic failure. Speed must stay within the manufacturer's limit.

Question 8Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the function of the air vessel (air chamber) fitted on the discharge side of a reciprocating bilge pump?

  1. To store spare compressed air for starting the engine
  2. To remove oil from the bilge water
  3. To smooth the pulsating discharge flow and reduce pressure surges Correct answer.
  4. To increase the pump suction lift

Explanation

Because a reciprocating pump delivers flow in pulses, an air vessel on the discharge acts as a cushion that evens out the flow and reduces surge pressures in the piping. It does not affect suction lift or water quality.

Question 9Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

During a routine watch, the main engine cylinder cooling water outlet temperature for one unit rises while all others remain steady. Which cause is most likely?

  1. A low level in the fuel oil settling tank
  2. A partially blocked cooling water passage or a sticking outlet valve on that unit Correct answer.
  3. An increase in the ship's speed through the water
  4. A general failure of the sea water pump

Explanation

A single-cylinder temperature rise while others are normal indicates a local restriction, such as fouled passages or a sticking valve, reducing flow through that unit only. System-wide faults would affect all cylinders together.

Question 10Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Which statement correctly describes the action of a diesel engine's fuel injection pump plunger with a helical groove?

  1. The helix controls the injection timing only and not the quantity
  2. The helix regulates the cooling water flow to the injector
  3. The helix controls the effective stroke and therefore the quantity of fuel delivered Correct answer.
  4. The helix sets the exhaust valve opening point

Explanation

On a helix-type injection pump, rotating the plunger changes where the spill port is uncovered, altering the effective stroke and thus the delivered fuel quantity. Timing is set separately by the camshaft and pump position.

Question 11Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Why is it important to maintain the correct concentration of corrosion inhibitor in the jacket cooling water of a marine diesel engine?

  1. To improve the heat transfer coefficient of the water
  2. To increase the boiling point of the cooling water
  3. To protect ferrous and non-ferrous components from corrosion and cavitation damage Correct answer.
  4. To reduce the viscosity of the lubricating oil

Explanation

Inhibitors form protective films that prevent corrosion and cavitation erosion of liners, heads and pumps. Too low a concentration allows corrosion; too high can cause deposits and reduced heat transfer.

Question 12Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A ship's steering gear is of the electro-hydraulic ram type. What is the purpose of the variable displacement pump in this system?

  1. To vary the oil flow to the rams and thus control rudder speed and direction Correct answer.
  2. To cool the hydraulic oil during operation
  3. To provide emergency manual steering
  4. To filter the hydraulic oil continuously

Explanation

By changing pump displacement, the oil flow to the rams is varied, which controls rudder angular velocity and direction. Centring the pump stops the rams and holds the rudder.

Question 13Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the main reason for fitting a relief valve on the discharge line of a positive displacement pump?

  1. To regulate the pump speed automatically
  2. To prime the pump before starting
  3. To protect the pump and piping from overpressure if the discharge is blocked Correct answer.
  4. To measure the flow rate of the pump

Explanation

A positive displacement pump will build pressure until something fails if its discharge is closed. A relief valve opens at a set pressure to bypass the flow and protect the pump and piping.

Question 14Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

During manoeuvring, the main engine must be reversed. What does the manoeuvring system normally do first?

  1. Disengage the propeller shaft brake before stopping the engine
  2. Open the indicator cocks and increase fuel rack setting
  3. Immediately admit starting air while fuel is still being injected
  4. Reduce engine speed and stop fuel injection before reversing the camshaft or air-starting in reverse Correct answer.

Explanation

Safe reversal requires the engine to slow and combustion to stop before the reversing mechanism or reverse starting air is applied. Applying starting air while fuel is injected can cause severe mechanical damage.

Question 15Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Which of the following best describes the function of the lubricating oil purifier in the main engine system?

  1. To raise the viscosity of the oil to the required grade
  2. To remove water and solid contaminants from the circulating lubricating oil Correct answer.
  3. To add anti-wear additives to the oil
  4. To cool the oil before it returns to the sump

Explanation

The purifier uses centrifugal force to separate water and solid impurities from the lubricating oil, helping maintain oil quality and protect bearings. It does not change viscosity grade or add additives.

Question 16Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A marine diesel generator engine shows black smoke at part load with normal exhaust temperature. Which cause should be investigated first?

  1. Incorrect air-fuel ratio due to a dirty air filter or turbocharger fault Correct answer.
  2. Low lubricating oil pressure
  3. Worn crankshaft bearings
  4. Excessive cooling water temperature

Explanation

Black smoke indicates incomplete combustion from too much fuel relative to available air, typically caused by restricted combustion air or poor turbocharger performance. Cooling water and oil pressure faults usually produce different symptoms.

Question 17Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the purpose of the starting air distributor on a large marine diesel engine?

  1. To distribute fuel to each injection pump
  2. To distribute lubricating oil to the main bearings
  3. To distribute cooling water to each cylinder jacket
  4. To direct starting air to the correct cylinder in the firing order during starting Correct answer.

Explanation

The starting air distributor is timed with the crankshaft to admit starting air to each cylinder in the correct sequence, producing rotation. It is part of the air starting system only.

Question 18Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A ship is fitted with an exhaust gas economiser producing steam. Why must the circulating water flow through the economiser be maintained when the main engine is running at low load?

  1. To prevent local overheating and evaporation of stagnant water in the tubes Correct answer.
  2. To increase the main engine exhaust back pressure
  3. To lower the boiler steam pressure
  4. To reduce the turbocharger speed

Explanation

Even at low engine load the exhaust gas still heats the economiser tubes; without adequate water flow, stagnant water can evaporate and cause local overheating or tube failure. Flow must be maintained whenever hot gas passes.

Question 19Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Which property of a hydraulic oil is most important for the correct operation of a steering gear system?

  1. Low specific gravity
  2. High water content
  3. Suitable viscosity index and anti-wear characteristics Correct answer.
  4. High flash point only

Explanation

Hydraulic oil must maintain adequate viscosity across the operating temperature range and provide anti-wear protection for pumps and rams. Flash point matters for safety but is not the primary performance property.

Question 20Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

During a crankcase inspection, oil mist is detected in the crankcase of a large diesel engine. What does this most likely indicate?

  1. An overfilled fuel tank
  2. Normal operation at high load
  3. A hot spot or incipient bearing failure causing oil to vaporise Correct answer.
  4. A low cooling water temperature

Explanation

Oil mist arises when lubricating oil is heated to vaporisation, often from a hot spot such as a failing bearing or piston. It is a serious warning sign and the engine should be investigated promptly.

Question 21Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the function of the sea water cooling system's central cooler in a diesel engine installation?

  1. To transfer heat from the fresh water cooling circuit to the sea water Correct answer.
  2. To heat the fuel oil before injection
  3. To provide water for the boiler feed system
  4. To supply cooling water directly to the cylinder jackets

Explanation

The central cooler is a heat exchanger that removes heat from the closed fresh water circuit and rejects it to the sea water. This keeps the jacket water within its treated, controlled circuit.

Question 22Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A main engine turbocharger begins to surge at high load. Which condition is a likely cause?

  1. Too low a lubricating oil temperature
  2. A high sea water temperature
  3. Excessive fuel rack setting at low load
  4. A fouled compressor or turbine causing a mismatch between engine air demand and turbocharger delivery Correct answer.

Explanation

Surge occurs when the compressor cannot deliver against the system pressure, often because fouling upsets the matching between turbocharger and engine. Cleaning or overhaul restores the balance.

Question 23Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Why is a compressor unloader fitted to a reciprocating air compressor used for starting air?

  1. To cool the compressed air
  2. To remove oil from the compressed air
  3. To increase the final delivery pressure
  4. To allow the compressor to start against a reduced load by relieving cylinder pressure Correct answer.

Explanation

An unloader holds the suction valve open or bypasses the cylinder during starting so the motor does not have to overcome full compression load. It also helps controlled stopping and restarting.

Question 24Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

What is the main consequence of excessive cylinder liner wear in a two-stroke marine diesel engine?

  1. Increased blow-by and loss of scavenge air, reducing combustion efficiency Correct answer.
  2. Improved sealing between piston rings and liner
  3. Lower lubricating oil consumption
  4. Higher scavenge air pressure in the receiver

Explanation

As the liner wears, the piston rings cannot seal effectively, so combustion gas and scavenge air leak past, reducing efficiency and raising contamination. Oil consumption typically rises rather than falls.

Question 25Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

Which action is required before opening up a fuel injection pump for maintenance on a running ship?

  1. Drain the lubricating oil from the sump
  2. Isolate the fuel supply, relieve pressure and ensure the engine cannot be started Correct answer.
  3. Open the indicator cocks and run the engine slowly
  4. Increase the fuel rack setting to clear the line

Explanation

Fuel systems are isolated, depressurised and locked out before maintenance to prevent injection injury and accidental starting. Running the engine or increasing rack during the work would be extremely dangerous.

Question 26Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a large two-stroke marine diesel engine, what is the primary function of the scavenge air receiver?

  1. It provides a volume of air at slightly above atmospheric pressure to scavenge the cylinder and support combustion. Correct answer.
  2. It separates water and oil from the crankcase blow-by gases.
  3. It acts as a silencer for the exhaust gas pulses from the turbocharger.
  4. It stores compressed air to supply the starting air system.

Explanation

The scavenge air receiver is a large chamber that collects air from the turbocharger compressor and delivers it to the scavenge ports at a pressure slightly above atmospheric, typically 0.5–1.0 bar. This air sweeps out exhaust gases and provides fresh air for combustion. It does not store starting air, silence exhaust, or separate crankcase gases.

Question 27Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A main engine fuel injection pump is fitted with a suction valve that is held closed during the pumping stroke. What is the purpose of this valve?

  1. To allow fuel to bypass the pump element during the pumping stroke for load control.
  2. To release excess pressure from the high-pressure line after injection.
  3. To prevent fuel from flowing back to the low-pressure supply during injection.
  4. To admit fuel into the pump barrel during the suction stroke and seal during injection. Correct answer.

Explanation

The suction valve opens during the suction stroke to admit fuel into the pump barrel and closes tightly during the pumping stroke to allow pressure to build for injection. It is not used for load control, which is achieved by spill valves or helical grooves. It does not release pressure after injection; that is the function of the delivery valve or a separate pressure relief valve.

Question 28Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a marine diesel engine, what is the main consequence of a leaking cylinder liner O-ring seal at the lower part of the liner?

  1. Fuel oil contaminates the cooling water, leading to a risk of explosion.
  2. Exhaust gas leaks into the cooling water system, causing air locks.
  3. Lubricating oil from the crankcase mixes with cooling water, forming an emulsion. Correct answer.
  4. Cooling water enters the scavenge air space, causing water carry-over and possible scavenge fire.

Explanation

The lower O-ring seals separate the cooling water space from the crankcase. If they leak, cooling water enters the crankcase and mixes with lubricating oil, forming an emulsion that degrades lubrication. Water in the scavenge air space would come from a leaking upper seal or cracked liner, not the lower O-ring.

Question 29Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A ship is equipped with a tubular type exhaust gas economiser. Why must a circulating water pump be kept running through the economiser even when the main engine is stopped?

  1. To prevent the economiser from freezing in cold weather.
  2. To keep the steam drum at operating pressure for auxiliary services.
  3. To maintain water quality by continuous filtration.
  4. To avoid overheating and tube damage from residual heat in the economiser. Correct answer.

Explanation

After the main engine stops, the economiser tubes remain hot and can overheat if water circulation stops, leading to thermal stress, tube distortion, or failure. The circulating pump dissipates residual heat and prevents steam pockets from forming. Freezing is not a concern in a hot economiser, and water quality is maintained by chemical treatment, not circulation alone.

Question 30Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A marine diesel engine is fitted with a hydraulic valve actuation system. During operation, the exhaust valve for one unit begins to close slowly. Which fault is the most likely cause?

  1. Worn rocker arm clearance.
  2. A broken valve spring.
  3. A leaking hydraulic pump relief valve.
  4. Air trapped in the hydraulic actuator cylinder. Correct answer.

Explanation

Air in the hydraulic actuator creates a compressible cushion that delays the build-up of pressure, causing slow or incomplete valve movement. A broken valve spring would typically cause the valve to close too quickly or not open fully. Worn rocker arm clearance applies to mechanical actuation, and a leaking relief valve would affect the whole system, not one unit.

Question 31Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a marine diesel engine, what is the function of the fuel injection pump's delivery valve unloading groove?

  1. To provide a calibrated leak for fuel return to the suction side.
  2. To increase the fuel delivery quantity at high load.
  3. To dampen pressure pulsations in the high-pressure line during injection.
  4. To allow a small amount of fuel to bypass the delivery valve after injection, reducing residual line pressure. Correct answer.

Explanation

The unloading groove on the delivery valve retracts a small volume of fuel after the valve closes, rapidly reducing residual pressure in the high-pressure line. This prevents secondary injection and dribbling at the nozzle. It does not increase delivery quantity, provide a calibrated leak, or primarily dampen pulsations during injection.

Question 32Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A ship's main engine is fitted with a central cooling system. What is the purpose of the temperature control valve (three-way valve) in the fresh water circuit?

  1. To isolate the fresh water circuit during maintenance.
  2. To regulate the sea water flow through the central cooler.
  3. To prevent excessive pressure in the fresh water system.
  4. To maintain the fresh water outlet temperature from the engine at the set point by bypassing some water around the cooler. Correct answer.

Explanation

The temperature control valve senses the fresh water outlet temperature and adjusts the flow either through or bypassing the cooler to maintain the set point. It does not isolate the circuit, regulate sea water flow (which is often controlled separately), or act as a pressure relief valve.

Question 33Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a marine diesel engine, what is the main reason for fitting a crankcase relief valve?

  1. To allow fresh air to enter the crankcase during cooling.
  2. To permit inspection of the crankcase interior during operation.
  3. To relieve excessive pressure in the crankcase caused by a blow-by or oil mist explosion, preventing crankcase rupture. Correct answer.
  4. To provide a means of draining excess lubricating oil.

Explanation

Crankcase relief valves are designed to open rapidly if pressure rises due to a crankcase explosion or excessive blow-by, preventing catastrophic rupture of the crankcase. They are not for ventilation, oil drainage, or inspection. They are a critical safety device.

Question 34Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A main engine turbocharger is fitted with a water washing system for the compressor. What is the primary purpose of water washing the compressor side?

  1. To remove salt deposits from the compressor blades.
  2. To remove dirt and carbon deposits from the compressor blades and diffuser. Correct answer.
  3. To lubricate the compressor bearings.
  4. To cool the compressor wheel during high-load operation.

Explanation

Water washing of the compressor removes dirt, carbon, and oil deposits that accumulate on the blades and diffuser, restoring efficiency and preventing imbalance. It is not for cooling, salt removal (which would require fresh water and is done on the compressor if salt is present, but the primary purpose is deposit removal), or lubrication.

Question 35Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

In a marine diesel engine, what is the effect of excessive valve lash (clearance) on the exhaust valve?

  1. The valve opens later and closes earlier, reducing effective opening duration. Correct answer.
  2. The valve opens earlier and closes later, increasing overlap.
  3. The valve opens later and closes later, maintaining duration.
  4. The valve opens earlier and closes earlier, increasing duration.

Explanation

Excessive valve lash delays the opening and advances the closing of the valve, reducing the effective opening period. This can lead to incomplete exhaust gas removal and reduced engine efficiency. The other options incorrectly describe the timing changes.

Question 36Marine Engineering Knowledge: Main Propulsion and Auxiliary Machinery

A ship is operating in cold weather, and the main engine starting air system has a drain trap that is not automatically draining. What is the most likely consequence?

  1. The air dryer will become ineffective, causing oil carry-over.
  2. The air compressor will run continuously, leading to overheating.
  3. The starting air pressure will increase excessively, risking receiver rupture.
  4. Water accumulation in the air receiver can lead to corrosion and carry-over of water into the starting air valves, causing malfunction. Correct answer.

Explanation

If the drain trap fails, condensate accumulates in the starting air receiver and lines. This can cause corrosion and, more critically, water carry-over into the starting air valves, leading to sticking or failure during manoeuvring. It does not cause pressure increase, continuous compressor running, or air dryer ineffectiveness.

Question 37Marine Electrical, Electronic and Control Engineering

On a Kazakhstan-flagged vessel, the emergency generator is required to start automatically and supply the emergency switchboard within what maximum time after the main power fails, under SOLAS II-1 requirements for ships built after 1 January 1998?

  1. 15 minutes
  2. 45 seconds Correct answer.
  3. 3 minutes
  4. 10 seconds

Explanation

SOLAS II-1 Reg. 43 requires the transitional emergency source to carry the emergency load within 45 seconds of loss of main power, with automatic starting. This 45-second window is the standard acceptance criterion during survey testing of emergency generator blackout start performance.

Question 38Marine Electrical, Electronic and Control Engineering

During insulation resistance testing of a 440 V three-phase distribution circuit with a 500 V DC insulation tester, the minimum acceptable reading for a new installation is normally taken as:

  1. 5 megohm
  2. 0.1 megohm
  3. 100 kilohm
  4. 1 megohm Correct answer.

Explanation

Classification practice for low-voltage marine circuits generally requires at least 1 megohm insulation resistance to earth when measured with a 500 V DC tester on a de-energised circuit. Readings below this indicate moisture, contamination or cable damage requiring investigation before the circuit is re-energised.

Question 39Marine Electrical, Electronic and Control Engineering

A three-phase induction motor driving a sea water pump trips its overload relay shortly after start while running lightly loaded. Which condition is the most likely electrical cause?

  1. Over-lubricated pump bearings
  2. Slightly low supply frequency
  3. Single-phasing caused by a blown fuse in one supply line Correct answer.
  4. Correct phase sequence at the motor terminals

Explanation

With one supply line open, the motor operates on a single-phase supply and the remaining windings carry greatly increased current for the same load, so the overload relay trips even at light mechanical load. Phase sequence and small frequency deviations do not produce this symptom, and bearing lubrication is mechanical rather than electrical.

Question 40Marine Electrical, Electronic and Control Engineering

The automatic voltage regulator of a ship's brushless alternator has failed and the machine is running on residual magnetism only. What output would you expect?

  1. Normal voltage only when the prime mover exceeds rated speed
  2. Rated voltage with reversed phase rotation
  3. A very low voltage, far below rated, that collapses under load Correct answer.
  4. Full rated voltage but unstable frequency

Explanation

Without excitation from the AVR the alternator relies on residual flux in the rotor, which produces only a small percentage of rated voltage that cannot be sustained under load. Frequency is set by the prime mover, so it is unaffected, and phase rotation depends on generator wiring, not excitation level.

Question 41Marine Electrical, Electronic and Control Engineering

Two generators are to be paralleled. Which conditions must be satisfied before the incoming generator breaker is closed?

  1. The incoming generator must be running at a higher frequency and voltage than the bus
  2. Only the voltages must be equal
  3. Voltage, frequency and phase angle must match the bus, with phase sequence correct Correct answer.
  4. Only the frequencies must be equal

Explanation

Synchronising requires matching voltage magnitude, frequency and phase angle between the incoming machine and the live bus, with correct phase sequence established at installation. Closing the breaker outside these conditions produces large circulating currents and mechanical shock to the set.

Question 42Marine Electrical, Electronic and Control Engineering

In a marine preference trip system, what is the purpose of the preferential trip relay when the generator is overloaded?

  1. To increase generator excitation to carry the overload
  2. To trip the main generator breaker immediately to protect the alternator
  3. To transfer the bus to the emergency generator without a blackout
  4. To shed non-essential loads in a defined sequence to prevent the generator breaker tripping Correct answer.

Explanation

Preferential tripping disconnects grouped non-essential consumers in stages so that the remaining load falls within generator capacity, avoiding a total blackout. It acts before the generator breaker trips on overload, and it does not manipulate excitation or transfer the bus.

Question 43Marine Electrical, Electronic and Control Engineering

A PLC input module receives a 24 V DC signal from a float switch, but the input LED flickers when the pump motor starts. The most appropriate first action is to:

  1. Check screening and separation of the signal cable from motor power cables and verify the common return Correct answer.
  2. Change the float switch to a normally closed contact
  3. Replace the PLC processor module
  4. Increase the PLC scan time

Explanation

Flicker synchronous with motor starting indicates electrical interference coupled into the signal wiring, so screening, cable routing and a sound common return should be verified first. Replacing the processor or altering scan time does not address the noise source, and contact configuration does not change susceptibility to interference.

Question 44Marine Electrical, Electronic and Control Engineering

Which statement correctly describes the function of the emergency switchboard on a cargo ship?

  1. It is the main distribution board for cargo winches and bow thrusters
  2. It distributes power only to the accommodation air conditioning system
  3. It is a section of the main switchboard that is isolated during manoeuvring
  4. It is supplied from the emergency generator or emergency battery and feeds essential services such as emergency lighting and steering gear alarms Correct answer.

Explanation

The emergency switchboard is a separately located board fed by the emergency source, supplying services required for safety such as emergency lighting, navigation lights and alarm circuits. It is not a cargo power board and must remain available after a main power failure.

Question 45Marine Electrical, Electronic and Control Engineering

A bridge navigational watch alarm system (BNWAS) is required on a Kazakhstan sea-going cargo ship. What is its primary function?

  1. To sound the general emergency alarm automatically on detection of fire
  2. To provide automatic steering on a preset track
  3. To monitor bridge activity and alert the master or another officer if the OOW becomes incapacitated Correct answer.
  4. To record the ship's position at fixed intervals for the voyage data recorder

Explanation

BNWAS monitors presence on the bridge through periodic reset actions and raises alarms in stages if the officer of the watch fails to respond, ultimately alerting the master or another qualified officer. It does not perform position logging, fire detection or track steering.

Question 46Marine Electrical, Electronic and Control Engineering

The ship's gyrocompass shows a steady heading error that increases slowly over several hours and does not respond to speed and latitude corrections. Which action is most appropriate?

  1. Recalibrate the autopilot gain
  2. Compare with the magnetic compass and GPS course over ground, then arrange gyro servicing and check the follow-up and settling controls Correct answer.
  3. Immediately switch to hand steering using the magnetic compass and log it as a compass failure
  4. Increase the gyro spin motor voltage

Explanation

A slowly growing heading error with the correction inputs applied suggests a gyro fault such as follow-up or settling drift, so cross-checking against independent references before arranging service is the correct diagnostic path. Autopilot gain and spin motor voltage do not correct heading reference errors.

Question 47Marine Electrical, Electronic and Control Engineering

In a marine fire detection system, what distinguishes a rate-of-rise heat detector from a fixed-temperature detector?

  1. It responds only to smoke density above a set level
  2. It responds to the speed of temperature increase rather than to an absolute threshold temperature Correct answer.
  3. It uses an ionisation chamber to sense combustion products
  4. It operates only when the ambient temperature exceeds 90 degrees Celsius

Explanation

A rate-of-rise detector triggers when temperature rises faster than a set rate, which allows earlier warning in a rapidly developing fire. A fixed-temperature detector operates only when a preset absolute temperature is exceeded, and smoke and ionisation devices respond to combustion products rather than heat.

Question 48Marine Electrical, Electronic and Control Engineering

The steering gear on a vessel must be capable of putting the rudder over from 35 degrees on one side to 35 degrees on the other side within what maximum time, with the ship at maximum ahead service speed?

  1. 60 seconds
  2. 10 seconds
  3. 28 seconds Correct answer.
  4. 90 seconds

Explanation

SOLAS II-1 Reg. 29 requires the main steering gear to move the rudder from 35 degrees one side to 35 degrees the other in not more than 28 seconds at maximum ahead service speed. This performance is verified during sea trials and periodic surveys.

Question 49Marine Electrical, Electronic and Control Engineering

A vessel's main switchboard is of the insulated-neutral type. What is the significance of this for earth fault detection?

  1. The system requires a solid neutral earth connection at the switchboard
  2. Earth faults cannot occur on an insulated system
  3. A single earth fault does not trip the circuit, so an earth fault monitoring system must alarm and the fault must be located and cleared Correct answer.
  4. Any earth fault immediately trips the affected circuit breaker

Explanation

On an insulated-neutral system a single earth fault does not cause large fault current, so protective devices will not operate and a dedicated earth fault monitor must alarm. The fault must be traced and cleared promptly because a second fault on another phase would create a phase-to-phase short through earth.

Question 50Marine Electrical, Electronic and Control Engineering

Which of the following is the correct purpose of the reverse power relay on a generator prime mover?

  1. To limit the generator stator current during a short circuit
  2. To trip the generator breaker if the generator starts motoring and drawing power from the bus Correct answer.
  3. To disconnect non-essential loads during overload
  4. To prevent the generator from exceeding its rated voltage

Explanation

A reverse power relay detects active power flowing into the generator from the bus, indicating the prime mover has lost power and the machine is motoring. Tripping the breaker protects the prime mover from damage. Voltage regulation, short-circuit current limitation and load shedding are functions of other devices.