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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BILGE ANSWERS

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
ţ    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
ţ  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
ţ         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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STEERING ANSWERS

 

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)