MEO CLASS IV exam is conducted by DG SHIPPING govt. of India. Below is the list of questions most frequently asked in meo class 4 MEP ( Marine engineering practice ) exam.

Precaution is taken to give all correct answers at the same time author is not responsible for any mistakes whatsoever.

These class 4 MEP questions and answers can be considered as a reference guide for your class 4 written exam.


Which of the following V/V cannot be overhauled in place without removing piping?

A. Ball Valve
B. Diaphragm valve
C. Globe valve
D. Butterfly valve *

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

A) Cavitation *
B) Erosion
C) Impingement Corrosion
D) Cavitation Erosion

Why should only approved toilet cleaning chemicals be used in

A. Unapproved chemicals can lead to corrosion in the system
B. unapproved chemicals can lead to toxic conditions in the system leading
C. To destruction of protective coatings
D. Unapproved chemicals can kill aerobic bacteria making the plant ineffective Gases produced by use of unapproved chemicals can pose threat to the operators *

After over hauling reciprocal pump the motor connections were wrongly given. Determine outcome when pump is started?

A) The direction of flow will remain unaffected *
B) the direction of flow will be reversed
C) The pump will get damaged because the suction valve will block the reverse flow causing overpressure leading to pump breakdown.
D) The pump will lose suction N there will be no flow.

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?

A. The cooling S.W. inlet temperature has reduced
B. The efficiency of the cooler has increased over a period of time
C. The cooler has become dirty on the S.W. side or L.O. side
D. S.W. side of the cooler may be partially blocked with mud and sea shells *

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:-

A. Fluidity only
B. Density only
C. Both fluidity and density *

D. Compressibility

Vacuum priming pumps which work on the principle of fixed vane pumps require for clearance between vane tips and casing.

A. Lube oil, lubricating
B. Lube oil, sealing
C. Water, sealing *

D. Gland packing, sealing

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?

A. Low suction pressure acting against the spring loaded clutching piston
B. High suction pressure acting against the spring loaded clutching piston
C. Low discharge pressure acting against the spring loaded clutching piston *

D. High discharge pressure acting against the spring loaded clutching piston

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?

A. Pump suction filter cover gasket leaking
B. Suction filter cover gasket of one of the Bilge wells is leaking
C. Bilge well suction pipeline leaking between individual bilge well valves and suction manifold valve *

D. Bilge pump suction pipeline leaking between the manifold and the pump


A. hot plating,
B. electrolysis,
C. explosion bonding, *

D. metal spraying

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?

A. Valve should be checked locally for troubleshooting without which it is difficult to find the exact problem *
B. The actuator must be defective and should be replaced with a new one
C. The control circuit is defective and the PCB should be replaced
D. Shore assistance will be required in such cases

It 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. There is leakage in the bilge suction pipeline somewhere between the bilge wells and bilge pump
B. The Fwd. (P) bilge well suction valve might be leaking
C. The Fwd. (P) bilge well suction filter cover gasket might be leaking *
D. The pump needs to be overhauled

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.

A) 5th engineer made a mistake by 1st transferring the fwd (s) bilge wel, normal sequence of operation for engine room machinaries should not b disturbed.
B) fwd (s) Bilge wel suction valve is leaking *

C) Bilge pump suction filter cover gasket is leaking.
D) Fwd (s) Bilgewel suction filter cover gasket is leaking.

The centrifugal pumps are normally

A) Positive displacement type
B) Rotodynamic *
C) Screw type
D) Gear type

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.

A) Pump is not working efficiently n reqd. overhauling
B) F>O> sludge tank suction valve is leaking
C) W.O. tank D.B. tank suction pipeline has a blockage. *

D) Can’t say what is the problem but definitely the pump needs to be opened up for overhaul

The difference between the discharges of a centrifugal pump n reciprocating pump the discharge of centrifugal pump is ———-while that if reciprocating is ———

A) Turbulent, Laminar
B) Intermittent continuous
C) Continuous pulsating *

D) Pulsating continuous


Which of the following is a true statement

A) Aluminum will be subject to preferential corrosion when in electrical continuity with stainless steel in presence of an electrolyte. *
b) Stainless steel will be subject to preferential corrosion when in electrical continuity with mild steel in presence of an electrolyte.
C) Copper will be subject to preferential corrosion when in electrical continuity with stainless steel in presence of an electrolyte
d) Aluminum will b subject to preferential corrosion when in electrical continuity with zinc in presence of an electrolyte.

NOTE:- The galvanic series determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while electrically connected, the less noble (base) will experience galvanic corrosion. Galvanic series s as follows – Graphite, Au, Ag, Titanium, Ni, Cu, Tin, Pb, Stainless steel, Cast iron, Mild steel, Al, Zn, Mg(least noble). Aluminum will corrode faster than stainless steel

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

A) Pump was drawing air fr.
B) Pump was drawing air from suction filter *

C) One of the pipe lines on the suction side of the pump might be leaking
D) The filter was not cleaned properly.

The most important control measure to prevent boiler tube failure is

A) Use of proper refractory mtrl.
B) Proper maintenance of fuel burning equipment
C) Proper maintenance of boiler water condition *

D) All of the above

When one of the M/E.F.O. heater is not in use then

A) The F.O. inlet n outlet valve should b kept shut, but steam heating valves should b kept crack open so as to keep the heater warm.
B) F.O. inlet n outlet valve should b kept shut n heating valves also should b completely shut n should b drained of any remaining F.O. *

c) F.O. inlet n outlet valve should b kept crack open so that the F.O. recirculation can take place.
d) F.O. inlet n outlet valve should b kept shut while outlet valve should be left open so that

The gland packing on centrifugal pump shaft should:

A. Not allow any leakage under positive suction pressure
B. Should only allow drop by drop continuous leakage under positive suction pressure *

C. Should only allow drop by drop continual leakage under positive suction pressure
D. Should allow considerable leakage as gland packings are meant to allow considerable leakage

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?

A. Presence of air cooler
B. Presence of Labyrinth seal
C. High speed of rotation , very fine internal clearances and large impeller diameters *

D. Difference in principle of operation

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?

A. Since marking was forgotten, so we need not worry, any impeller can come in any place as they are identical
B. Any impeller can come in any place, but the phase sequence of the electrical motor driving the pump may have to be reversed, if impellers have exchanged places
C. You have to find out the right placement of the right impeller with respect to the direction of rotation or by looking at the volute casing *
D. Hit an trial method will have to used to find out the correct placement method by assembling the pump and trying it out


The delivery rate of an axial piston hydraulic pump is controlled by varying the position of the .

  1. Tilting box *
  2. Slide block
  3. Pintle
  4. Reaction ring

Who gives hotwork permit on drydock

a. C.E.
b. 2.E
c. Superintendent
d. Dock engineers *

High pressure cut out in ref. system, activated when

A. low cooling in condenser *
B. air in the system *
C. over charge *

D. none of the above

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

a. Do nothing
b. Inform chief *
c. It is an indication that your OWS is working normally
d. It is a practice that OWS is discharged with flushing water throttle

The corrosion protection for Cooling Fresh Water systems of Marine Diesel Engines is normally provided by:

A. Sacrificial anodes
C. Protective Metal coatings of system components
D. Addition of corrosion inhibitors to the Cooling Fresh water *


The temperature of the refrigerant is highest just before it enters the
a. frosting region
b. evaporator
c. condenser *
d. gage pressure

What does it signifies if during your watch you hear a sound of an oil mist detector alarm?

A. There is leakage of cooling water to the crankcase
B. There is a dangerous accumulation of gases in the crankcase *
C. It could be a false alarm but needs confirmation *

Hot corrosion in exhaust valves and fire side of boiler mainly when:

A. Fuels containing vanadium content with high sodium content are used *
B. Fuels containing vanadium content with low sodium content are used
C. Fuels containing high vanadium and high sulphur content are used
D.Fuels containing high sulphur content is used and the exhaust temperatures are uncontrolled and exceed 600 deg. C

Why are large centrifugal pumps started with their discharge valves closed?

A. To ensure proper priming
B. To limit sudden rise in discharge rate
C. To limit motor starting current *
D. To minimize starting torque on motor shaft

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:

A. Pump is not operating satisfactorily and pumping capacity is too low
B. Pump is not operating satisfactorily and pumping capacity is higher than rated, throttling of discharge valve is required
C. Pumping capacity is not affected by suction and discharge pressures
D. Pump is operating normally *

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?

A) There is nothing more to b done, if you know the valves are holding u can straight away start opening the heater without wasting time.
B) Drain the heater till pressure gauge reads zero n then start opening the heater.
C) Drain the heater till F.O. stops coming out of the drain n then start opening the heater.
D) First open the vent valve n allow the heater to depressurize. N then open the drain valve to drain the contents of the heater. *

During flooding of dry dock following items must be verified?

A) All sea valves are operational
B) All overboard discharge valves r operational
C) Stern tube seal are operational
D) All above *

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