OOW Questions Help

[kingzola]

I am preparing for my OOW Examinations and the following questions has been giving me tough time, Please I would love the following questions to be answered
Thanks

Question 1
Explain how the cause of the following bilge pump faults are identified, traced and rectified
(a) unable to empty bilge
(b) Unable to empty one bilge
(c) Only possible to empty one bilge slowly

Question 2
What are the probable cause if:
(a) Pump does not deliver the rated capacity
(b) Pump Discharge pressure is low
(c) Stuffing box overheat
(d) Pump loses prime after starting
(d) pump fails to deliver liquid

Question 3
Write brief comment on how the following can affect centrifugal pump performance
(a) Wear Rings
(b) Impeller erosion
(c) Gland sealing
(d) Shaft Wear
(e) Speed

Question 4
State the different energies stored in a liquid in motion

Question 5
Explain how a ship can be steered in the following circumstances
(a) Destruction by fire of primary supply cables
(b) Destruction by fire of telemotor line
(c) Bearing failure of running pump

[Anish]

(a) unable to empty bilge

The Strum Box from the Bilge may be Fouled.
Bilge Pump Suction Strainer may be blocked.
A Valve may be left open from an Empty Bilge.
There could be a hole in the System on the Suction Side of the Pump.
Depending on type of Bilge Pump, the Pump Suction or Discharge Valves may need overhauling.

(b) Unable to empty one bilge


That bilge well suction valve is closed
Clogged strianer
Hole in the suction pipe above bilge level

(c) Only possible to empty one bilge slowly
-Other empty bilge valve is open
bilge well suction valve is closed

[John Pierce]

Re Question 4: A liquid in motion, such as water in a centrifugal pump, has pressure energy and kinetic energy. These energies can be converted from one to the other. For example, the volute casing of a centrifugal pump causes the liquid to slow down due to the increasing cross-sectional area of the volute. The kinetic energy is thus reduced while the pressure energy increases. On the other hand, the nozzle on the end of a fire hose has a decreasing cross sectional area so the pressure energy in the water is converted into kinetic energy of the fast moving stream of water coming out of the nozzle.

[John Pierce]

Re Question 5: This is what SOLAS says about steering gear and should answer your questions: "Unless expressly provided otherwise, every ship shall be provided with a main steering gear and an auxiliary steering gear to the satisfaction of the administration. The main steering gear and the auxiliary steering gear shall be so arranged that the failure of one of them will not render the other one inoperative".