MOTOR
AUXILIARIES EXERCISE: BILGE-QUESTIONS NAME:
1. Bilge pumps in a surveyed vessel must:
¨ be protected by strums,
strainers or mud boxes
¨ be of a type, size and number as specified for the vessel
¨ have a separate power source when more than one pump is specified
¨ all of the above
2.
Describe the main difference between strainers and mud boxes.
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3.
What would happen to the bilge pumping system if a strainer
was leaking around the lid?
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4. The most appropriate (single) valve to use in a bilge suction line would
¨ Gate valve
¨ Butterfly
valve
¨ Screw-down non-return valve
5. A centrifugal pump is full of air due to
maintenance on the strainers and suction pipes. What will happen when the
pump motor is started?
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6. In a flexible impeller pump, water flows to the outlet because:
¨ centrifugal force
flings water to the outside discharge
¨ the impeller lobes are bent by the offset
plate, squeezing the water out
¨ the steel rotor distorts the rubber stator,
forcing the fluid from the pump
¨ one-way flap-valves ensure the water only
goes to the outlet
7. In a bilge system using strainers and
centrifugal pumps, list the maintenance checks which should be regularly carried
out.
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8. “Strums must be mounted in the bottom
of the vessel to protect the end of a suction pipe, but strainers may be mounted
higher where they are easier to reach!” How can pump suction draw bilge through
the strainer without sucking air at the strainer?
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9. Sketch below the basic components of a surveyed 12 metre vessels bilge system.
1. Bilge pumps in a surveyed vessel must:
¨
be protected by strums, strainers or mud-boxes
¨ be of a type, size and number as specified for the vessel
¨ have a separate power source when more than one pump is specified
þ all of the above
2. Describe the main difference between strainers and mud-boxes.
A mud box is similar to a strainer but has a dam
at the base of the strainer plate.
Solids dropping off the strainer plate are retained in the dam, and prevented
from falling back down the suction pipe into the bilge.
3. What would happen to the bilge pumping system if a strainer
was leaking around the lid?
The bilge pump would suck air and may
stop pumping
4. The most appropriate (single)
valve to use in a bilge suction line would be:
¨ Gate
valve
¨ Butterfly valve
þ Screw-down non-return
valve
¨ Sleeve-packed cock
5. A centrifugal pump is full of air due to maintenance on the
strainers and suction pipes. Explain
what will happen when the pump motor is started.
The pump is full of air, and centrifugal
pumps are not self-priming, so it will not pump This may damage pump seals if the pump
is not shut-down and primed.
6. In a flexible impeller pump, water flows
to the outlet because:
¨ centrifugal force flings water to the
outside discharge
þ the impeller lobes are bent by the offset
plate, squeezing the water out
¨ the steel rotor distorts the rubber stator,
forcing the fluid
¨ one-way flap-valves ensure the water only
goes to the outlet
7. In a bilge system using strainers and centrifugal pumps–list
the maintenance which should be regularly carried out.
Strainers should be regularly cleaned
and re-sealed, and pump seals and suction piping checked for leaks.
8. “Strums must be mounted in the bottom
of the vessel to protect the end of a suction pipe, but strainers may be mounted
higher where they are easier to reach!” How can pump suction draw bilge through
the strainer without sucking air at the strainer?
Strainers are sealed, and effectively
form part of the suction piping.
STEERING-QUESTIONS
1. Match the following hydraulic steering systems with their descriptions:
a.
Direct System ....... 1 The movement of the steering wheel serves
only to control the power
hydraulics.
b.
Indirect System ....... 2 The movement of the steering wheel supplies
the hydraulic power to
move the rudder.
2.
“Dual ram steering systems can be used to increase steering force,
and at the same time may be arranged to reduce side thrust on the rudder post!”
TRUE
FALSE
3. Describe two different types of cables
which can be used for cable steering systems.
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4. What is the disadvantage of using flexible
multi-strand steel cable for steering systems?
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5. With direct hydraulic steering, the pressure relief valve closes when large seas hit the rudder.
TRUE FALSE
6.
How can hydraulic components be protected against contaminants in the
hydraulic oil?
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7. Describe two maintenance checks on a steering
system.
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1. Match the following hydraulic steering systems with their descriptions:
a.
Direct System ....... b 1 The movement of the steering wheel serves
only to control the power
hydraulics.
b.
Indirect System ....... a 2 The movement of the steering wheel supplies
the hydraulic power to
move the rudder.
2.
“Dual ram steering systems can be used to increase steering force,
and at the same time may be arranged to reduce side thrust on the rudder post!” TRUE
3.
Describe two different types of cables which can be used for cable
steering systems.
Flexible multi-strand pull
only cable.
Semi-rigid push-pull sheathed cable.
4.
What is the disadvantage of using flexible multi-stand steel cable
for steering systems?
Pulleys and rollers have to be mounted
to run the cable in suitable areas, and to allow the rudder to be pulled in
either direction.
5. With direct hydraulic steering, the pressure relief valve closes when large seas hit the rudder. FALSE
6.
How can hydraulic components be protected against contaminants in the
hydraulic oil?
By the use of appropriate
strainers and filters.
7.
Describe two maintenance checks on a steering system.
Resevoir fluid level……for leaks
Ranger Hope © 2005 (contains reworked material
courtesy of ANTA)