Aux 1 Unit 11 Q12

1 / 10

How is the aft seal typically arranged in relation to the propeller shaft?

B) The aft seal is placed at the bow of the vessel.

A) The aft seal is mounted directly on the propeller shaft and housed within the stern tube seal assembly.

D) The aft seal is located on the rudder.

C) The aft seal is positioned inside the engine room.

2 / 10

What could be a potential consequence of a failed aft seal in an oil-lubricated stern tube bearing?

A) Increased vessel speed

B) Seawater ingress into the stern tube, leading to contamination of the lubricating oil, and potential damage to the bearings and shaft

D) Improved propulsion efficiency

C) Reduced fuel consumption

3 / 10

What additional component might be included in the aft seal arrangement to protect the seal from damage caused by debris or fishing lines?

B) A rubber washer

D) A plastic cap

A) A metal guard ring or rope guard

C) A wooden cover

4 / 10

Why is it important to monitor the condition of the aft seal in an oil-lubricated stern tube bearing?

B) To detect any signs of wear or damage that could lead to leaks, ensuring the seal continues to protect the stern tube from seawater ingress and oil leakage

D) To increase the weight of the vessel

A) To increase the vessel's speed

C) To reduce the vessel's draft

5 / 10

What type of seal is commonly used for the aft seal in an oil-lubricated stern tube bearing?

B) A lip seal or face seal

A) A rubber O-ring

C) A metallic gasket

D) A cork seal

6 / 10

What maintenance procedure is typically performed to ensure the aft seal remains effective?

A) Heating the seal assembly

C) Painting the seal assembly

B) Regular inspection and replacement of the seals if wear or degradation is observed

D) Tightening the propeller shaft bolts

7 / 10

What material is commonly used for the lip seals in an aft seal arrangement?

B) Metal

A) Plastic

D) Wood

C) Synthetic rubber or a composite material resistant to oil and seawater

8 / 10

What is the purpose of the water cooling system often found in conjunction with the aft seal arrangement?

A) To cool the engine

C) To increase the speed of the vessel

D) To heat the propeller shaft

B) To reduce the temperature of the lubricating oil and prevent overheating of the seal assembly

9 / 10

How is the aft seal assembly typically lubricated?

D) With engine oil

C) With grease applied manually

B) With a dedicated supply of lubricating oil from the stern tube lubrication system

A) With seawater

10 / 10

What is the primary function of the aft seal in an oil-lubricated stern tube bearing?

C) To increase the speed of the vessel

D) To reduce the weight of the propeller shaft

B) To prevent the ingress of seawater into the stern tube and the leakage of lubricating oil into the sea

A) To cool the propeller shaft

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