STCW Marine Engineering 2

Question 1

What is the purpose of a jacket water cooling system on a marine diesel engine?

Accepted Answer

To maintain cylinder and head temperatures within safe operating limits

Answer

The jacket water cooling system circulates fresh water around cylinders and heads to prevent overheating and maintain safe metal temperatures.

Question 2

Which type of pump is most commonly used as the main bilge pump on a vessel?

Accepted Answer

Self-priming reciprocating or diaphragm pump

Answer

Self-priming reciprocating or diaphragm pumps are preferred for bilge service because they can handle air and debris without losing prime.

Question 3

In a four-stroke diesel engine, during which stroke does combustion occur?

Accepted Answer

Power (expansion) stroke

Answer

Combustion begins near TDC at the end of the compression stroke and the expanding gases drive the piston down during the power stroke.

Question 4

What does the term 'scavenging' refer to in a two-stroke diesel engine?

Accepted Answer

Clearing exhaust gases and filling the cylinder with fresh air

Answer

Scavenging is the process of expelling exhaust gases from the cylinder and replacing them with fresh charge air before the next compression stroke.

Question 5

What is the function of a turbocharger on a marine diesel engine?

Accepted Answer

To compress air supplied to the engine to increase power output

Answer

A turbocharger uses exhaust gas energy to drive a compressor that increases air density into the cylinders, enabling more fuel to be burned and raising power output.

(STCW) Standards Certification and Watchkeeping for Seafarers Practice Test

(STCW) Standards Certification and Watchkeeping for Seafarers Practice Test

STCW Marine Engineering 2