Aux 1 Unit 12 Q4

1 / 10

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

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

A) To reduce noise levels

C) To increase the flexibility of the shaft

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

2 / 10

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

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

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

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

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

3 / 10

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

D) To reduce the propeller thrust

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

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

C) To increase the weight of the thrust block

4 / 10

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

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

C) Reduced thrust transmission

D) Increased vibration transmission to the hull

A) Increased efficiency

5 / 10

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

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

C) To increase the flexibility of the thrust block

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

A) To rotate the thrust block

6 / 10

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

A) Through the engine directly

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

C) Through the propeller shaft bearings only

D) By the gearbox alone

7 / 10

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

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

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

C) To increase the load on the thrust block

8 / 10

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

B) The thrust collar on the propeller shaft

C) The gearbox casing

D) The rudder

A) The main engine

9 / 10

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

D) The shaft will move more freely

A) The thrust block will operate more efficiently

C) The thrust block will produce more noise

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

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

A) The bedplate must be made of wood

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

D) The thrust block should be mounted without bolts

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

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