Propeller, Shafting & Stern Tube Bearing(Set 1) MCQ

1. Which combination of the main shaft segments listed below, that are located furthest from the main engine, are connected by the inboard stern tube shaft coupling?

Line shaft and thrust shaft

Line shaft and stern-tube shaft

Thrust shaft and stern-tube shaft

Stern-tube shaft and tail shaft

2. Which of the following statements describes the purpose of the split inflatable seal installed aft of the primary seal assembly for the propeller shaft?

To serve as a seal when adding packing to the stuffing box.

To allow repair or replacement of the primary seal elements when the ship is waterborne.

To eliminate leakage via the propeller shaft when the shaft is not rotating.

To provide a ready means for the entry of cooling water.

3. The exposed portion of the outboard propeller shaft is protected against seawater corrosion by ________________.

a heavy lubricant

a covering of plastic, rubber, or shrunk-on composition sleeve

a corrosion-resistant paint

a layer of oxidation formed when the metal of the shaft is exposed to seawater

4. Water leaking through the stern tube stuffing box is used to accomplish which of the following actions?

Cooling

Lubrication

Flushing

All of the above

5. One of the determining factors regulating the time interval for drawing a vessel's tailshaft depends upon the design to reduce stress concentrations in accordance with Class standards. Which construction method meets this design criteria?

Spooned keyway and slotted key

Stress relief grooves at the aft end of the propeller and forward end of the liner

Keyway cut as to give a sharp rise from the bottom of the keyway to the shaft surface

All of the above

6. Some vessels are equipped with a water lubricated stern tube. When at sea, operating under normal conditions, the water service valve from the ship's saltwater system to the bearing should be ________________.

closed, and no leakage permitted across the shaft packing

closed, and only slight leakage permitted across the shaft packing

open, and only slight leakage permitted across the shaft packing

open, and no leakage permitted across the shaft packing

7. An excessive amount of water is prevented from entering a vessel using a water lubricated stern tube bearing by the use of the ________________.

propeller hub

lignum vitae

shaft packing

labyrinth seal

8. The device used to retain the packing, that keeps water from entering the ship through the opening where the propeller shaft passes through the hull, is called a ________________.

packing nut

hawsepipe

stuffing box

seal cage

9. If water were a semisolid, the linear distance a propeller would advance in one revolution is the ________________.

blade thickness fraction

mean width ratio

pitch

skew back factor

10. Excessive propeller vibration may occur as a result of ________________.

operating at low speed

high water pressure under the hull

cavitation

operating in deep river channels

Propeller, Shafting & Stern Tube Bearing (Set 1)

Multiple Choice Questions