Who gives hotwork permit on drydock
The water from discharge side of the a centrifugal pump is supplied as sealing water to the stuffing box for the pump shaft at:
Which of the following statements about pipe repairs is true?
Why are large centrifugal pumps started with their discharge valves closed?
What does it signifies if during your watch you hear a sound of an oil mist detector alarm?
Resistance to corrosion of Aluminium alloys is due to:
The ballast valve of the fore peak tank is located in the duct keel and cannot be opened or shut by remote operation. The valves of other tanks can be operated remotely without any trouble. Which of the following will be the best practice?
Process of enrichment of surface of steel and steel alloys by zinc using Electroplating is known as
It is given that engine room bilge pump has suction manifold on which 3 valves are located. One valve for the 3 engine room bilge wells suction, another one for Bilge tank suction and the third one will be for ______________.
The difference between the discharges of a centrifugal pump n reciprocating pump the discharge of centrifugal pump is ----------while that if reciprocating is ---------
has been reported that Engine room bilge pump was unable to take suction from Fwd. (P) bilge well while it taking suction efficiently from Fwd. (S) & aft bilge wells. What could be the most probable cause?
A ball valve is found leaking in service and needs to be overhauled. What type of repairs can be carried out?
Ballast pump injection filter was cleaned and the pump was lined up it was found that there was some leakage in the suction filter suction. The pump started and the leakage started. During de blasting it was found that the pump could not take suction from one of the double bottoms. The cause could be
Vacuum priming pumps which work on the principle of fixed vane pumps require ___________ for___________ clearance between vane tips and casing
The gland packing on centrifugal pump shaft should:
Why should only approved toilet cleaning chemicals be used in
Hot corrosion in exhaust valves and fire side of boiler mainly when:
A ballast pump is being used to de ballast a fore peak tank which is full. It is seen that suction pressure is positive and discharge pressure is very low compared to rated discharge head. It indicates that:
In shell and plate type coolers, due to improper flow design or partial blockage of tubes may lead to high turbulence locally. This condition may lead to (choose the best alternatives):
If the direction of rotation of a gear pump is reversed due to change in-phase sequence, what happens when the pump is started?
While stopping purifier abnormally vibrating, reason:
After O'Hauling pumps, pumps cannot be turned freely by hand, the possible cause could be
The centrifugal pumps are normally
Screw pump generally are ________pump
OWS is observed to be operating in flushing water when you took watch and it suddenly stopped with an alarm when you tried to close bypass valve what will be your action
It is a known fact that centrifugal pumps require priming for pumping liquids, as they cannot handle air and will lose suction due to air entry. But on the other hand T/Cs use centrifugal compressors for supercharging. Which of the following do you think makes a centrifugal compressors to pump air and behave differently than the centrifugal pumps?
When pressure inside a system falls below that of the vapour pressure of the liquid cavities are formed, cavities travelling to high pressure region collapses releasing considerable energy damage the metal surface which is known as
For the S.W. side of a M/E L.O. cooler it is noticed that rise in S.W. temperature through the cooler has decreased from 12 deg. C to 7 deg. C over a period of time, while the drop in temperature of L.O. across the cooler has also decreased. All other coolers have been reported to be working normal & M/E is also running at a constant load in calm weather. What is the inference drawn by decrease in the temperature difference?
When one of the M/E.F.O. heater is not in use then
Resistance testing should be ideally done on electrical equipment when the equipment is:
A ballast pump is being used to de-ballast a fore peak tank which is full. It is seen that suction pressure is positive and discharge pressure is very low compared to rated discharge head. It indicates that:
Which of the following option gives you the correct sequence of the metals in increasing order of nobility in galvanic series
After over hauling reciprocal pump the motor connections were wrongly given. Determine outcome when pump is started?
Which valve is not quarter turn valve? (Globe valve also)
During flooding of dry dock following items must be verified?
The delivery rate of an axial piston hydraulic pump is controlled by varying the position of the __.
The temperature of the refrigerant is highest just before it enters the __________.
Butterfly vv stuck in half open position. How to repair
WHICH PROCESS IS NOT DONE ON MILD STEEL?
Centrifugal pumps cannot handle air and require priming. But you are aware that centrifugal which on the same principal can handle air very well. Which two properties of air are responsible because of which the centrifugal pumps cannot handle air:-
U R responsible for daily transfers of engine room bilges. You follow the sequences aft –fwd (P)-fwd(s) bilge well and you have never experienced a problem but 5/E started the transfer n first transferred forward (s) bilge well and without any problem and you join him later you find that bilge pump is not taking suction from fwd (p) and aft bilge well and then you have checked everything is normal. What is the cause.
Which of the following V/V cannot be overhauled in place without removing piping?
The corrosion protection for Cooling Fresh Water systems of Marine Diesel Engines is normally provided by:
You have a two stage centrifugal pump, with both stages in parallel configuration. After dismantling the pump you realize that you forgot to the marking and both impellers are identical. Both the impellers are single entry type and the eye of both the impellers will come in opposite direction What are you going to do?
High pressure cut out in ref. system, activated when
It is given that engine room bilge pump has suction manifold on which 3 valves are located. One valve for the 3 engine room bilge wells suction, another one for Bilge tank suction and the third one is for sea water suction. It is found that the Bilge pump is unable to take suction from any of the bilge wells, but is able to take suction efficiently from Bilge tank. What is the most probable cause?
You have to dismantle a F.O. heater for cleaning. You have closed both inlet n outlet valves of the heater, both for F.O. and steam side. What will U do before u start opening the heater?
Sludge pump suction pressure is going full vacuum when u start the pump a taking water of double bottom tank suction you have checked the suction filter and found in clean condition. Taking suction from fuel oil sludge tank does not happen. Causes of the problem.
Pump driven clutch type attached vacuum pumps are commonly used for priming ballast pumps and emergency fire pumps. What is the factor which clutches the vacuum pump clutch to the pump clutch during start of the pump?
Super chlorinating of fresh water tanks in dry dock is done by: