Aux 1 Unit 12 Q4

1 / 10

Why is it important to maintain the correct clearance between the thrust block pads and the collar?

A) To allow the thrust block to rotate with the shaft

D) To allow the thrust block to move freely within the hull

B) To ensure that the thrust is evenly distributed across the thrust block, preventing localized wear and potential failure

C) To increase the load on the thrust block

2 / 10

What component of the propulsion system directly transmits the propeller thrust to the thrust block?

A) The main engine

B) The thrust collar on the propeller shaft

C) The gearbox casing

D) The rudder

3 / 10

What is the role of the bedplate in the mounting arrangement of a thrust block?

D) To reduce the friction between the shaft and the hull

B) To provide a stable and secure base for the thrust block, ensuring that the thrust is effectively transmitted to the hull

A) To rotate the thrust block

C) To increase the flexibility of the thrust block

4 / 10

What is a common mounting arrangement for a thrust block to the hull?

B) The thrust block is mounted on a bedplate that is bolted to the hull and often includes flexible mounts or shock absorbers to reduce vibrations

D) The thrust block is mounted on the propeller shaft without connection to the hull

C) The thrust block is suspended in mid-air using wires

A) The thrust block is directly bolted to the hull structure without any cushioning

5 / 10

Why is it important for the thrust block to be securely mounted to the hull?

B) To ensure that the thrust from the propeller is effectively transmitted to the hull, enabling the vessel to move forward

D) To allow the thrust block to move with the shaft

C) To increase the flexibility of the shaft

A) To reduce noise levels

6 / 10

What additional consideration must be made when mounting a thrust block on a bedplate in a ship's hull?

D) The thrust block should be mounted without bolts

A) The bedplate must be made of wood

C) The bedplate should be flexible enough to move with the hull

B) The alignment of the thrust block with the propeller shaft must be precisely maintained to avoid misalignment issues

7 / 10

What could happen if the clearance between the thrust block pads and the collar is too tight?

A) Increased efficiency

B) Excessive friction, leading to overheating and potential damage to the thrust block and collar

D) Increased vibration transmission to the hull

C) Reduced thrust transmission

8 / 10

Why are flexible mounts or shock absorbers used in the thrust block mounting arrangement?

C) To increase the weight of the thrust block

B) To reduce the transmission of vibrations and shocks from the propeller shaft to the hull

D) To reduce the propeller thrust

A) To allow the thrust block to move with the shaft

9 / 10

What is the potential consequence of having too much clearance between the thrust block pads and the collar?

C) The thrust block will produce more noise

A) The thrust block will operate more efficiently

D) The shaft will move more freely

B) The thrust may not be fully transmitted, leading to slippage and uneven wear, which can reduce the efficiency and effectiveness of the propulsion system

10 / 10

How is the thrust generated by a propeller transmitted to a vessel's hull?

C) Through the propeller shaft bearings only

B) Via the thrust block, which transfers the thrust from the propeller shaft to the vessel’s hull

D) By the gearbox alone

A) Through the engine directly

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