Shipping Industry

Marine Engineering Practice Question Papers for Class 4B MMD exam- Part 3

1.      A few valves on
the valve chest of a bilge pump, on the suction side, need urgent
repair/renewal. Write a letter to the owner asking for spares, clearly
indicating the type of valve, the components required and the approximate time
for the repair.

2.      Suggest some
means of aligning a pump and its drive motor which are mounted on a common cast
iron base and joined by a flexible coupling.
3.      A boiler water
feed pump, which used to run very smoothly, gradually starts to vibrate and
make noise. Excepting for a small variation in ampere load of the drive motor,
all other parameters like pressure , r.p.m, voltage, etc. are normal. Suggest
some causes for this unusual behavior.
4.      A Fresh water
cooler for the auxiliary engine
is stripped open during overhaul for survey
purposes. State out a list of components; parts or areas, which you would like
to particularly check  yourself before
the survey.
5.      A Lubricating Oil
Purifier
vibrates moderately when just about to stop. Your inspection of the
drive mechanism bowl etc reveals nothing unusual. Suggest some parts you would
inspect that are built in to restrict vibration, keep the shaft aligned in
place and reduce shaft deflection owing to torsion.
6.     
In machine shop practice, a thread gauge is used for
checking ______________.
(a)     
needle and thread
(b)     
screw threads
(c)     
screw thread pitch
(d)    
thread cutting tools
Briefly justify
your answer.
7.     
Which of the fittings listed below should be used
for the jointing of pipes in the pipeline installations for a drinking water
system in the accommodation of a ship?
(a)     
Universal Coupling
(b)     
Pipe jointing Union
(c)     
Instantaneous Coupling
(d)    
Reducing Nipple
Briefly justify
your answer.
8.     
Which of the listed conditions can lead to cavitation
in a centrifugal pump?
(a)     
Vapor pockets formed in the suction flow stream.
(b)     
Rough casing volute surfaces.
(c)     
Worn wearing rings.
(d)    
Heavy fluid in the flow stream.
Briefly justify
your answer.
9.     
The process of removing moisture from air is known
as _____________.
(a)     
humidification
(b)     
dehumidification
(c)     
vaporization
(d)    
evaporation
Briefly justify
your answer.
10.  A centrifugal
bilge pump
requires priming ________________.
(a)     
primarily to lubricate the shaft seals
(b)     
due to the inability of this type of pump to lift
water to cover the suction (eye) of the impeller
(c)     
to initially unload the pump by having its head
pressure equal to discharge pressure
(d)    
in order to overcome the potential energy of water
in the discharge line
Briefly justify
your answer.
 11.      Give instructions
in writing to the support crew suggesting a repair procedure for a large Main
Sea Water pump whose foundation bolts keep breaking very often.
12.      Elaborate on any
two types of welding joints used in joining large diameter pipes in a ships
engine room.
13.      The Lube Oil
cooler of a large two stroke marine diesel engine is showing poor performance.
Suggest some measures you would initiate to rectify the problem and improve the
performance.
14.      Write short notes
on the following:
(A)  Hardness testing
(B)   Magnetic particle
examination
(C)   Noise
measurements
(D)  Strain gauge
technology
15.     
The gasket and the broken studs have been replaced
on a tank manhole cover. Which of the following methods is satisfactory for
testing the repair?
(A)   
Pressurize the tank with 0.8 kg/cm2 air,
soap the repaired area, watch for visible signs of leakage or bubbles.
(B)   
Fill the tank with water via the ballast pump until
the ullage reading corresponds to the maximum depth of the tank.
(C)   
Hose test the repaired area with a minimum of 6
kg/cm2 water pressure.
(D)   
Fill the tank via the ballast pump until water flows
from the vent line opening on deck.
Briefly Justify
your answer
16.     
The static suction lift of a pump is the difference
in elevation between the _____________.
(A)   
centerline of the pump and the level of the liquid
in the suction well when the source of liquid is below the pump
(B)   
centerline of the pump and the suction liquid level
when the source of liquid is above the pump
(C)   
centerline of the pump and the level of the
discharge liquid
(D)   
liquid levels of the suction and discharge
Briefly Justify
your answer
17.     
Piping cross-sections ranging from 3mm to 30cm in
diameter, are sized by ____________.
(A)   
wall strength
(B)   
nominal inside diameter
(C)   
outside diameter
(D)   
threaded diameter
Briefly Justify
your answer
18.     
If a radial piston hydraulic pump fails to deliver
rated fluid volume, the cause can be _______________.
(A)   
contaminated fluid
(B)   
pitted thrust rings
(C)   
worn pintle bearings
(D)   
obstructed suction passage
Briefly Justify
your answer
19.     
Pipe threads are cut with a taper to ____________.
(A)   
prevent overtightening the joint
(B)   
provide a leakproof fit
(C)   
permit easy joint disassembly
(D)   
produce a fine even thread
Briefly Justify
your answer
20.  Which of the
refrigerants listed is considered safe and ideal for most marine applications?
(A)   
R-21
(B)   
Ammonia
(C)   
R-12
(D)   
Sulfur dioxide
Briefly Justify
your answer
READ  Crankshaft Deflection and Bearing Clearance Measurement
Mark Eriscson
Love to write about topics related to maritime sector. Was born in sailor's family, so love to ride on those high seas. In free time i would like to go for a good sunbath and some soothing guitar music. Want to have my own boat one day.

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