300 top questions and answers for Marine Engineers Interview Part-2

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Marine Engineers Q and A Part 2- The best Interview Tips

The questions and answers for a marine engineer interview are essential for several reasons:

  1. Assessment of Technical Knowledge: The interviewer can assess the technical knowledge and expertise of the candidate in marine engineering through these questions.
  2. Understanding of Industry Standards: The answers to these questions can give the interviewer an understanding of the candidate’s awareness of industry standards and best practices in marine engineering.
  3. Problem-Solving Skills: Some questions may test the candidate’s problem-solving skills and ability to apply their knowledge to real-world scenarios.
  4. Communication Skills: The answers to these questions can also demonstrate the candidate’s communication skills and ability to articulate technical information effectively.
  5. Career Aspirations: The questions may also give the interviewer insight into the candidate’s career aspirations, motivations, and goals in the marine engineering field.

Overall, the questions and answers for a marine engineer interview play a crucial role in evaluating a candidate’s suitability for a marine engineering role.

Read the related post:- 300 top questions and answers for Marine Engineers Interview Part-1

300 top questions and answers for Marine Engineers

Q 1- Which standards govern the specifications for supply of Residual Marine Fuels and Distillate Marine Fuels onboard merchant ships?

Ans- The specifications for the supply of The type of coating typically provided on the valve stem of exhaust valves in modern marine diesel engines is Stellite. Stellite is a type of cobalt-based alloy that provides excellent resistance to wear, erosion, and high temperature corrosion, making it ideal for use in high-stress, high-temperature environments like those found in marine diesel engines. and Distillate Marine Fuels onboard merchant ships are governed by the International Maritime Organization’s (IMO) International Convention for the Prevention of Pollution from Ships (MARPOL) and the International Standard for Bunker Delivery Note (ISBN 9785291534119). Additionally, the ISO 8217 standard provides specifications for the quality of marine fuels.

Q 2- What will be indicated by Crank web deflection readings ?


Ans- Crank web deflection readings indicate the amount of bending or flexing of the crankshaft at the web, which is the part connecting the main journal to the crank throw. High readings can indicate excessive stress or loading on the crankshaft, potentially due to improper engine assembly, unreasonable engine load, or other issues. These high readings can be a warning sign of potential damage or failure if not addressed.

Q 3- What is the advantage of tie rods over the Marine engine?

Ans- The advantages of tie rods over tie rodless engines are:
The engine is very easy to align after misalignment occurs between the various components of the engine. The engine uses tie rods to transmit thrust to the hull, eliminating the need for thrust pads.

Q 4- What is The purpose of an air cooler in a supercharging system?

Ans- Incorporating an air cooler in a turbocharger system reduces the compressed air temperature before it enters the engine. Reducing the charge air temperature is done to increase the air density and improve engine efficiency. The reason being cold air is denser and contains more oxygen. Air coolers help avoid pre-ignition and detonation that can occur when compressed air overheats and its temperature exceeds the ignition temperature of the fuel. Air coolers cool the air, allowing the engine to produce more power with the same amount of fuel.

Q 5- Why is it essential to renew turbocharger bearings after a preset number of hours of running even if the bearings are in seemingly perfect condition?

Ans- Renewing turbocharger bearings after several hours is considered a preventive maintenance measure. However, the bearings may appear in good condition Because they are subject to cyclic loading and prone to failure due to metal fatigue. Renewing the bearings before this happens can help ensure the longevity and reliability of the turbocharger and the overall engine system. Additionally, renewing the bearings allows one to inspect the turbocharger for other potential issues and make any necessary repairs.

Q 6- Which type of compressor is used in Modern marine turbochargers ?

Ans- Modern marine turbochargers typically use a radial compressor.

turbo compressor wheel min

Q 7- Which type of lube oil pump used in a diesel engine ?

Ans– In diesel engines, a gear type lube oil pump is commonly used.

Q 8- What type of coating is provided on the valve stem of exhaust valves of modern marine diesel engines ?

Ans-The type of coating typically provided on the valve stem of exhaust valves in modern marine diesel engines is Stellite. Stellite is a type of cobalt-based alloy that provides excellent resistance to wear, erosion, and high temperature corrosion, making it ideal for use in high-stress, high-temperature environments like those found in marine diesel engines.

Q 9- What is the function of Top and lower O ring on Cylinder liner of 2 stroke engine?

Ans- The top and lower O-rings on a cylinder liner of a 2-stroke engine serve as seals. The top O-ring seals the combustion chamber, preventing the mixture of fuel and air from leaking out. The lower O-ring seals the crankcase, preventing the lubricating oil from entering the combustion chamber. These seals are important for maintaining proper compression and lubrication in the engine.

Q 10- What is the purpose or rotocap in cylinder head valves ?

Valve Rotator min

Ans- A rotocap in the cylinder head valve protects the valve stem and provides a better seal. A rotocap is a round metal cap that fits over the top of the valve stem and is held in place by a spring. The cap rotates as the valve opens and closes, reducing friction and wear on the stem. Additionally, the roto cap helps to keep dirt and debris out of the valve train, preventing contamination that can cause valve damage or poor performance. By providing a better seal, roto caps also improve engine performance and efficiency by reducing the amount of oil escapes past the valve stem.

Q 11-What do you mean by surge limit of a turbocharger?

Turbocharger surging 1

Ans- The surge limit of a turbocharger refers to the maximum air flow rate that the turbocharger can handle without experiencing a surge, which is an unstable and loud knocking sound caused by the airflow reversing direction within the compressor. It occurs when the airflow demand suddenly drops, causing the compressor to stall and the air to reverse direction. To prevent this, turbochargers are designed with a surge limit, which sets the maximum air flow rate that the compressor can safely handle to avoid surges.

Q 12- Which type ot turbochargers need exhaust grouping ?

Ans- Exhaust Grouping is required in case of pulse pressure turbocharging to prevent interference with the scavenging of other cylinders

Q 13- What would be the rtesult of jerk type fuel pumps wear on the top edge of plunger and edges of spill ports and helix due to erosion by high pressure fuel as it spills ?

Ans- Wearing the top edge of the plunger and edges of spill ports and helix due to erosion by high-pressure fuel as it spills can cause a late start and early end of injection.

Q 14- What is the function of Labyrinth seal fitted on the back surface of a compressor wheel of a turbocharger ?

Ans- The labyrinth seal on a turbocharger’s back surface of a compressor wheel helps to prevent oil and hot gases from leaking from the high-pressure side of the turbocharger into the low-pressure side. It creates a labyrinthine path of ridges and grooves that slows the flow of air and gases and prevents them from escaping. This helps maintain the turbocharger’s efficiency and performance and protects the bearings and other components from damage caused by oil and hot gases.

Q 15- Which of the fuel oil impurities can cause maximum abrasive damage?

Ans- Catalytic fines can cause the maximum abrasive damage in Engine.

Q 16- Which of the statements correctly describes the phenomenon of surging in a 2- stroke crosshead type engine?

Ans- Surging in a 2-stroke crosshead type engine is a phenomenon where, Due to a sudden decrease in engine load the turbocharger pressure ratio drops. This causes high pressure downstream of T/C in scavenge trunk causing flow reversal of scavenge airThis can lead to vibration, increased fuel consumption, and reduced engine efficiency.

Q 17- Which instrument would you use to check the setting of the over-speed trip on a diesel-powered generator?

Ans- You would typically use a tachometer to check the setting of the over-speed trip on a diesel-powered generator.

Q 18- Which of the specifications/qualities of cylinder oils counter corrosive wear?

Ans- Cylinder oils with high TBN Value, anti-wear properties, high film strength, and high detergency effectively counter corrosive wear. These properties help to form a protective film on metal surfaces, reducing friction and protecting against corrosion caused by acidic and corrosive combustion by-products. Additionally, cylinder oils with good rust and oxidation resistance help prevent corrosion.

Q 19- What is meant by elastohydrodynamic lubrication?

Ans- Elastohydrodynamic lubrication (EHL) refers to the lubrication regime in which high pressure is generated between two surfaces in relative motion, and the surfaces deform elastically to form a thin liquid lubricant film. This lubrication is essential in many engineering applications, particularly gears, rolling element bearings, and journal bearings.

Q 20- How to to reduce the cold corrosion of Main Engine cylinder liners using high sulphur fuel oil?

Ans- The use of high TBN (Total Base Number) cylinder oil can help reduce cold corrosion of Main Engine cylinder liners caused by high sulfur fuel oil. TBN is a measure of the reserve alkalinity of the oil, which helps neutralize acidic compounds formed during the combustion of high-sulfur fuel. By maintaining a high TBN level, cylinder oil helps prevent corrosion in the cylinder liners. Ensuring proper fuel injection, combustion conditions, and effective scrubbing of combustion gases can also help reduce cold corrosion.

Q 21- When main engine is running in emergency condition which of the alarms can’t be bypassed?

Ans- In emergency conditions, specific alarms cannot be bypassed for safety reasons. The LO low pressure, jacket water high temperature, and piston cooling water high-temperature alarms indicate potential issues with the main engine, and bypassing them could damage the engine or other equipment or compromise the safety of the crew and ship. It is best to follow standard operating procedures to address the alarms and resolve the underlying issues before continuing to operate the engine.

Q 22- Which steps should be taken to reduce sulfur corrosion of main engine parts?

Ans- Reducing sulfur corrosion in main engine parts can be achieved by taking a combination of the following steps:
A. Decreasing the sulfur content of the fuel oil by using fuels with lower sulfur content or treating the fuel with a desulfurization process.

B. Increasing the F.O. purifier feed rate to reduce the fuel oil’s sulfur content to a level lower than the engine’s tolerance.

C. Maintaining good fuel injector atomization to ensure that the fuel is burned completely, reducing the formation of sulfur compounds.

D. Increasing the engine’s ventilation to remove sulfur compounds from the engine room and to prevent their accumulation in the engine’s components.
Additionally, regular maintenance of the engine and its components can help minimize the effects of sulfur corrosion, including cleaning, inspecting, and repairing damaged parts, as well as applying anti-corrosion coatings to exposed surfaces.

Q 23-  What is necessary to avoid the engine running too long on critical speed during start up?

Ans- Starting an engine at speeds just below critical speed and quickly moving across it helps prevent the engine from running too long at critical speed during start-up, which can cause damage to the engine. This practice is common in the operation of many rotating machinery systems.

Q 24- What happens when you supercharge an existing medium-speed naturally aspirated engine?

Ans- Supercharging an existing engine can increase its power output, but it may also increase fuel consumption, depending on the design and tuning of the system. Supercharging compresses the air entering the engine, allowing it to burn more fuel and produce more power. However, the extra energy required to run the supercharger must also be considered, which can offset the gains in fuel efficiency. The net effect on fuel consumption will depend on the specific design and tuning of the system.

Q 25- What should be the ideal TBN when using low sulfur fuel oil in Emission Control Areas (ECAs)?

Ans- The TBN (Total Base Number) of cylinder oil used in ships using low sulfur fuel oil in Emission Control Areas (ECA’s) should be lower than normal.

Q 26- Which of the functions is done by a cam operating an exhaust valve?

Ans- The following functions are done by a cam operating an exhaust valve?
A. It governs the timing of the opening and closing of the valve.
B. It governs the speed at which the valve operates
C. It governs the amount of opening of the valve

Q 27- In the latest variable geometry turbocharger concept, which component angles can be varied to adapt the turbocharger at different engine loads?

Ans- In a Variable Geometry Turbo (VGT) system, the nozzle ring blade angle can be adjusted to optimize turbocharger performance at different engine loads. Change of nozzle ring blade angle allows for better control over the boost pressure generated by the turbocharger, leading to improved engine efficiency and responsiveness.

Q 28- Why does a chain stretch in service?

Ans- A chain stretch in service Due to wear on rollers and bushes

Q 29-  How the muffling of exhaust gas noise in 4 stroke auxiliary engines in achieved?

Ans- The muffling of exhaust gas noise in 4-stroke auxiliary engines is achieved by allowing the gas to expand and change the direction of its flow.

Q 30- What are the reasons for the sudden stoppage of diesel engines?

Ans- A sudden stop of the diesel engine will happen due to the following reasons
A. air in the system
B. water in the system
C. air filter chocked

Q 31-When A/E stand by F.O. heater to be used for main engine ?

Ans- F.O. inlet valve causes pressure drop M/E F.O. pressure standby water is not pressurized may causesudden change in engine /per load/rpm

Q 32- Which of the types of damages are metal seatings of a valve subject to?

Ans- Following types of damages are metal seatings of a valve subject to . Corrosion, Erosion, Abrasion, Deformation.

Blog Conclusion

In conclusion, Marine Engineering is a complex and challenging field that requires a high level of technical expertise, critical thinking, and interpersonal skills. As such, the interview process for marine engineers can be quite competitive, and it is essential to be well-prepared. In this blog’s second part, we covered some of the most common questions that you might encounter in a marine engineering interview and provided tips for how to answer them effectively.

To recap, it is crucial to demonstrate your knowledge of industry standards, your ability to work as part of a team, and your passion for the field. Finally, make sure to practice your answers and to come prepared with questions of your own to show your interest and enthusiasm for the position. Good luck!

Hi, I’m Sham, Founder of marinediesel.co.in. A web site that provides authentic information regarding Marine Diesel Engines, and learn marine Engineering free with us

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