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.
means of aligning a pump and its drive motor which are mounted on a common cast
iron base and joined by a flexible coupling.
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.
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
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.
In machine shop practice, a thread gauge is used for
needle and thread
screw thread pitch
thread cutting tools
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?
Pipe jointing Union
Which of the listed conditions can lead to cavitation
in a centrifugal pump?
Vapor pockets formed in the suction flow stream.
Rough casing volute surfaces.
Worn wearing rings.
Heavy fluid in the flow stream.
The process of removing moisture from air is known
bilge pump requires priming ________________.
primarily to lubricate the shaft seals
due to the inability of this type of pump to lift
water to cover the suction (eye) of the impeller
to initially unload the pump by having its head
pressure equal to discharge pressure
in order to overcome the potential energy of water
in the discharge line
in writing to the support crew suggesting a repair procedure for a large Main
Sea Water pump whose foundation bolts keep breaking very often.
two types of welding joints used in joining large diameter pipes in a ships
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
on the following:
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?
Pressurize the tank with 0.8 kg/cm2 air,
soap the repaired area, watch for visible signs of leakage or bubbles.
Fill the tank with water via the ballast pump until
the ullage reading corresponds to the maximum depth of the tank.
Hose test the repaired area with a minimum of 6
kg/cm2 water pressure.
Fill the tank via the ballast pump until water flows
from the vent line opening on deck.
The static suction lift of a pump is the difference
in elevation between the _____________.
centerline of the pump and the level of the liquid
in the suction well when the source of liquid is below the pump
centerline of the pump and the suction liquid level
when the source of liquid is above the pump
centerline of the pump and the level of the
liquid levels of the suction and discharge
Piping cross-sections ranging from 3mm to 30cm in
diameter, are sized by ____________.
nominal inside diameter
If a radial piston hydraulic pump fails to deliver
rated fluid volume, the cause can be _______________.
pitted thrust rings
worn pintle bearings
obstructed suction passage
Pipe threads are cut with a taper to ____________.
prevent overtightening the joint
provide a leakproof fit
permit easy joint disassembly
produce a fine even thread
refrigerants listed is considered safe and ideal for most marine applications?