this series. We have covered topics like Steam, Liner, Control air, Sea Water
Line, Expansion tank, Sump, Spanners, O- Rings, Mechanical Seal and Crankshaft
Deflections. Questions given here might be useful for you if you are sailing on
ship or giving your officers exam.
second article in this series here:
What Fittings are there on
fitting that you find on a steam line:
Reducing Valve for low pressure applications
Blow Down Valve
Pressure and Temperature Gauge
What are the indications that
your liner is cracked?
indications if your engine liner is cracked:
You will see pressure changes in the cooling
water system of jacket water. Mostly during compression, and expansion.
You will see that water is coming from the
At the expansion tank, you will see foaming taking
Higher exhaust temperature and also the jacket
cooling water temperature.
Smoke will be little white in color.
What are the fittings on the
control air line from the main air bottle?
Pressure reducing valve
Strainer on the line
Drain Valve for moisture
Air Dryer to remove moisture
Five ways to stop leakage in the sea water
can stop the leakage,
With a wooden dart inserted in to the hole.
By welding plate or normal brazing.
Using rubber pad and circle clip.
Cement box is also one method.
Using material like davcon.
Making threads in the pipe and putting a stud or
bolt in it.
Auxiliary Engine sump going up
in your watch, what can be the reasons?
Valve for filling oil is not holding.
Valve arrangement from the purifier has been set
Jacket water is leaking in to the sump.
Fuel oil is leaking in to the sump.
Too much blow by leading to the combustion
products to find their way to the sump.
Expansion Tank Purpose and what
it is called otherwise?
so all the water vapors generated in the cooling system, will be related here.
Also, compensation for any type of water will be made here. Chemical to the
system are made from here. The other name of this tank is De-Aerator.
Why spanner length increases
of the torque. Since Torque is defined as the product of the force and the
perpendicular distance. So, more the distance, lesser the force that you have
to apply while opening or tightening. This is the reason why, spanner length is
increased as the size increases.
How to make o-ring if you don’t
o-ring material. Cut a piece for it. Now cut the end, at a 45 degree angle, so
that maximum contact can be there when you will join the two ends together. Use
locatite or whatever joining adhesive you have onboard to join the ends. Keep
it for half hour, and you are ready with your O-Ring.
Mechanical Seal leaking, you
don’t have spare, how to repair?
carefully. Take the seal (mostly carbon made), clean with soft rag. Now put
some clean lube oil on the chart paper or glass. Smoother surfaces are always
welcomed. Now put the seal over it, and lap it. Generally it is advisable not
to use any lapping paste, even the fine ones.
Reason for taking crank shaft
about the condition of main bearing. Consider a situation when a rod is placed
over two supports. These two supports are equal in height. So, if you apply
force and turn the rod, there will be no deflections.
in unequal height (consider two adjacent main bearings), the rod will hog or
sag depending on the difference of height. Same goes with the engine crankshaft.
When you take deflection, the crank web will either hog or sag, depending on
the main bearing clearances.