Aux 1 Unit 11 Q5

1 / 10

What feature in a plain bearing system allows for longitudinal movement of the shaft?

A) Fixed bearing housings

B) Thrust collars that restrict shaft movement

D) Rigid coupling systems

C) The use of axial clearances or a floating bearing design that permits the shaft to slide within the bearing

2 / 10

What is a key reason why other intermediate bearings may only have the bush in the lower half?

B) Because the weight of the shaft provides sufficient downward force, reducing the need for full circumferential support in intermediate positions

D) To allow for easier removal of the shaft

A) To reduce the cost of the bearings

C) To increase the speed of the vessel

3 / 10

What could happen if the propulsion shaft is not allowed to move longitudinally?

A) The shaft would operate more efficiently.

D) The shaft would become lighter.

B) Excessive stress could build up, leading to bearing failure or shaft damage.

C) The bearings would last longer.

4 / 10

Why might thermal expansion of the shaft be a concern in a marine propulsion system?

B) It causes the shaft to lengthen, potentially leading to misalignment or excessive stress if not accommodated.

A) It increases the speed of the vessel.

D) It increases the vessel's draft.

C) It reduces the need for lubrication.

5 / 10

How does the design of the aftmost bearing help to prevent shaft misalignment as the shaft exits the vessel?

D) By increasing lubrication flow

A) By allowing the shaft to move freely

B) By providing continuous support around the entire shaft circumference, ensuring that the shaft remains centered and aligned

C) By reducing the diameter of the shaft

6 / 10

What would be the consequence of not having a complete bush in the aftmost bearing?

D) Enhanced vessel speed

B) Increased risk of shaft misalignment, leading to potential damage or failure as the shaft exits the vessel

A) Improved bearing performance

C) Reduced friction and wear

7 / 10

How do plain bearings accommodate changes in alignment due to varying vessel conditions, such as loading or flexing of the hull?

B) By incorporating a flexible support or pivot system that allows the bearing to adjust to minor alignment changes

D) By increasing the shaft diameter

A) By using fixed, rigid bearings

C) By reducing the size of the bearings

8 / 10

What type of bearing design feature helps accommodate alignment changes in a vessel?

A) Rigid bearing housings

D) Non-lubricated bearings

B) Spherical or self-aligning bearings

C) Fixed bushings

9 / 10

Why is it important for the propulsion shaft to be able to move longitudinally within its bearings?

D) To reduce the need for lubrication

B) To accommodate thermal expansion and contraction of the shaft, preventing excessive stress on the bearings and the shaft

A) To increase the vessel's speed

C) To decrease the weight of the shaft

10 / 10

Why does the aftmost bearing in a propulsion shaft system require a complete bush?

B) To provide full circumferential support to the shaft, preventing any lateral movement and maintaining alignment as the shaft exits the vessel

C) To reduce the weight of the shaft

A) To decrease lubrication needs

D) To increase shaft flexibility

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