Marine Engineering Interview Questions and Answers
Question - 21 : - With Reference To Bridge Control Of A Large Man B&w Slow Speed Propulsion Engine Explain How Starting And Reversal Are Achieved ?
Answer - 21 : -
For large propulsion engines the Bridge Control is achieved by using the telegraph to select the desired speed and direction. When the bridge telegraph is placed in Stop, the fuel is prevented from injecting as the fuel pump puncture valves are energised. When the bridge telegraph is moved to an ahead command, the air start and fuel cams are placed in the required direction, and the start command is given. This will admit starting air to the engine. Once the engine is turning above the starting speed, the air is closed and fuel is admitted.
The quantity of fuel admitted will depend on the position of the telegraph handle, i.e. slow ahead, full ahead, etc. When the bridge telegraph is moved to an astern direction, the air start and fuel cams are reversed. Once the air start is reversed, the engine will start as detailed for the ahead start.
Question - 22 : - Describe The Investigation And Remedial Action Required If The Engine Fails To Turn On Air ?
Answer - 22 : -
If the engine fails to start on air the following points would be investigated, and remedial action taken.
- No air pressure at engine manifold. The valves from the air receiver would be checked, and opened if found shut.
- Low air pressure at engine manifold. This could indicate that the air compressors are either not working or excess air is being used. All air compressors would be started, and air usage restricted to engine manoeuvring only.
- Turning gear engaged. The turning gear position and the interlock switch would be visually checked. The gear would be removed if found engaged.
Question - 23 : - Describe The Investigation And Remedial Action Required If The Engine Turns On Air But Fails To Fire On Fuel ?
Answer - 23 : -
If the engine fails to fire on fuel the following points would be investigated, and remedial action taken.
- Check for any shut-downs still active. The shut down panel would be examined, and if a trip is active the cause would be investigated and system made operational. Following this the trip reset button would be pressed.
- Low fuel pressure at the engine manifold. The fuel system would be investigated, and all valves checked to be opened, and all booster and supply pumps checked for running.
- Sticking fuel linkage. The action of the fuel linkage would be checked during the start sequence. The fuel linkage should admit a “starting level” of fuel after the engine start sequence has been completed. The physical movement of the fuel linkage would be checked, and any mechanical friction reduced by lubrication.
Question - 24 : - Describe The Investigation And Remedial Action Required If The Engine Fails To Reverse ?
Answer - 24 : -
If the engine fails to reverse the following points would be investigated, and remedial action taken.
- Air start distributor not reversing. The engine controls would be moved ahead and astern whilst observing the movement of the air start distributor. If the distributor is not moving, then the air servo cylinder would be checked to ensure that it is free to move, and that air is being admitted and vented as required to achieve the movement required.
- Air start valve not opening. It is possible that the air distributor does reverse as expected, but that the required air start valve would not open to rotate the engine in the new direction. This would be investigated by turning the engine in the ahead direction so that it stops in a new position. The engine would again be tested in the astern direction to test if a starting air valve has failed to open. Any valve found faulty would be removed, freed and refitted.
Question - 25 : - Why Self Closing Sounding Pipes Are Used Onboard?
Answer - 25 : -
It may possibly regulatory but I definitely know the US Coastguard pick up on it. It is for the fact a tank may be overfilled. A self closing sounding pipe will prevent overflow.
Question - 26 : - How Ships Are Flooding?
Answer - 26 : -
Ships can be flooded due to rupture of its hull due to several reasons such as collision, grounding, and or poor hull maintenance by which corrosion may eat away the hull. Also for warships it could be of battle related exchange of firing.
Question - 27 : - What Is Specific Fuel Consumption And How Fuel Calculate?
Answer - 27 : -
Generally it refer to the fuel consumtion rate, there are several deferent way to catlculate the specific fuel consuption, such as volumetric method and flow method. but these methods can be taken only in lab. no possible do it on the sea.
Question - 28 : - What Is High Temperature Corrosion And What Is Center Priming?
Answer - 28 : -
When material exposed to high temperature atmospehic situation like high level of oxygen presence, sulfer presence and different type chemical presence cause matrial worsening . This type of material corrosion is known as High temperature corrosion.
Question - 29 : - What Is The Purpose Of O-ring, Wearings In The Centrifugal
Answer - 29 : -
O-ring : to prevent leakage between metal parts while allowing some movement between them.
wear ring : generally a softer material than the parent material , employed to wear out quickly than the parent metal thereby avoiding loss of parent metal.
Question - 30 : - What Is The Different Between Gate Valve And Globe Valve?
Answer - 30 : -
Gate valve is non regulator means full close or full open positions only, while globe valve is regulator.