Shaft line

Question 1

What is the purpose of the Thrust block?

Answer 1

To absorb the forces by the action of the propeller and transmit them to the ships hull

Question 2

What is the purpose of the plummer block?

Answer 2

Used to support the weight of the shaft without absorbing thrust. The bearing lubricates it’s self using michelle’s principle.

Question 3

What is the purpose of bulkhead glands?

Answer 3

To maintain watertight integrity as the shaft passes through compartments without absorbing thrust

Question 4

What is the purpose of a stern seal?

Answer 4

Maintains watertight integrity as the shaft passes through the ships hull and acts as a mechanical seal

Question 5

What is the purpose of main A and intermediate A brackets

Answer 5

They support the weight of the propeller shaft and prevent whipping. The brackets do not take thrust

Question 6

What is the purpose of the SKF coupling?

Answer 6

It connects the intermediate shaft to the tail shaft, the SKF coupling can separate the two shafts for maintenance purposes. It is connected back together via the use of HP hydraulic oil.

Question 7

Purpose of the propeller?

Answer 7

The action of the blades turning in the water converts rotary motion to axial thrust.

Question 8

What are the two types of propellor?

Answer 8

Controlled pitch propellor - allows the pitch of the blades to change angle, oil is pumped down the shaft to move the blades, no reverse gearbox required.

Fixed blade - uses the generic propellor principles of converting rotary force to axial thrust, highly efficient but demands high power, loss of efficiency at low powers and astern