USCG General Engineering 5

Question 1

What is the purpose of a 'coffin plate' in a marine boiler?

Accepted Answer

A reinforcing plate used at the junction of the furnace and boiler shell

Answer

A coffin plate (also called a gusset stay) reinforces the structural junction between the furnace and the boiler shell to resist pressure-induced stress.

Question 2

Which condition would cause a centrifugal pump to cavitate?

Accepted Answer

Suction pressure falling below the vapor pressure of the liquid

Answer

Cavitation occurs when suction pressure drops below the liquid's vapor pressure, causing vapor bubbles to form and then collapse violently, damaging the pump impeller.

Question 3

What is the correct action if the 15 ppm bilge alarm activates while overboard discharge is underway?

Accepted Answer

Immediately stop the overboard discharge and divert to a holding tank

Answer

MARPOL requires immediate cessation of discharge when oil content exceeds 15 ppm; the oily water must be diverted to a slop or holding tank.

Question 4

What is the purpose of a 'stuffing box' (packing gland) on a centrifugal pump?

Accepted Answer

To prevent leakage along the pump shaft where it exits the casing

Answer

A stuffing box contains packing material compressed around the pump shaft to minimize fluid leakage where the rotating shaft passes through the stationary pump casing.

Question 5

In marine electrical systems, what does a 'dead front' switchboard mean?

Accepted Answer

A switchboard where all live parts are enclosed and inaccessible from the front

Answer

A dead front switchboard has all energized conductors and bus bars enclosed behind the front panel, reducing the risk of accidental contact by personnel.

USCG - United States Coast Guard Practice Test

USCG - United States Coast Guard Practice Test

USCG General Engineering 5