Transmissions

Question 1

The Function of the main gearbox is….?

Answer 1

Change direction

Change speed

Question 2

Describe the profile of Gear teeth-

Straight cut/ spur

Answer 2

Most common type

Cut so leading edge is parallel to the shaft

Noisy

Question 3

Describe the profile of Gear teeth-

Helical

Answer 3

Cut at and angle,to allow smoother meshing of gears

quieter

Question 4

Describe the profile of Gear teeth-

Double Helical

Answer 4

Same as helical but doesn’t need thrust bearings

Question 5

Describe the profile of Gear teeth-

Worm and Wheel

Answer 5

Where shafts are 90degrees to each other.

Worm is always the driver

Question 6

Explain how gearwheels change direction & speed

Answer 6

• Direction can be changed by adding a second gear to the first
• Speed can be changed by adding different size wheels

Question 7

The driving gear/input gear is called?

Answer 7

Primary pinion

Question 8

The Driven gear is called?

Answer 8

Primary wheel

Question 9

What is the purpose of the Shaft Brake?

Answer 9

To stop and hold the propeller shaft

Question 10

What is the thrust block?

Answer 10

it absorbs the force of the propeller so the ship moves ahead/astern

Question 11

What is Turning gear used for?

Answer 11

Used to slowly rotate the shaft and propeller in a controlled manner for docking & maintenance

Question 12

What is the Forced lubrication system?

Answer 12

It provides lub to the gearbox

Question 13

What is the Serckstat?

Answer 13

It directs Hot lub oil through the cooler & allows cool oil bypass the cooler

Question 14

Name the Hazards associated with Gearboxes

Answer 14

1. Noise
2. Heat/Fire
3. Rotating parts
4. (Overalls to be worn & man below tally procedure to be followed)

Question 15

Plummer blocks are…?

Answer 15

Used to support the weight of the shaft, without absorbing any thrust.

And keeps shaft aligned

Question 16

What is the purpose of bulkhead glands (Hogging & Sacking)

Answer 16

To maintain watertight integrity as the shaft passes through compartments

Question 17

what does the Stern Seal do?

Answer 17

Maintains a water tight seal as the shaft passes through the ships hull

Question 18

Main & Intermediate A Brackets…

Answer 18

Support the weight of the propeller shaft

Question 19

SKF coupling…

Answer 19

A hydraulic coupling designed so the tail shaft can be split from the intermediate shaft with out leaving a flange

Question 20

Describe propellers

Answer 20

1. Fixed blade
2. Blade angle/pitch cannot be changed
3. Efficient at full power
4. less efficient at low powers & when moving astern

Question 21

What is single gear reductions

Answer 21

High speed input gets reduced

Question 22

What is double gear reductions?

Answer 22

Reduces speed further

Question 23

What are the 3 Brake APPLICATION checks?

Answer 23

1. No fire risks
2. All brake are applied
3. Shaft is stationary

Question 24

What are the 3 Brake RELEASE checks?

Answer 24

1. All Pads are clear
2. No fire risks
3. Shaft is turning