STCW Marine Engineering 2 — Questions and Answers
Question 1: What is the purpose of a jacket water cooling system on a marine diesel engine?
- To lubricate cylinder walls
- To maintain cylinder and head temperatures within safe operating limits (Correct answer)
- To cool the fuel oil before injection
- To condense steam from the exhaust
Correct answer: To maintain cylinder and head temperatures within safe operating limits
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?
- Gear pump
- Centrifugal pump
- Self-priming reciprocating or diaphragm pump (Correct answer)
- Axial flow pump
Correct answer: Self-priming reciprocating or diaphragm pump
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?
- Suction stroke
- Compression stroke at TDC
- Power (expansion) stroke (Correct answer)
- Exhaust stroke
Correct answer: Power (expansion) stroke
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?
- Removing carbon deposits from pistons
- Clearing exhaust gases and filling the cylinder with fresh air (Correct answer)
- Circulating lube oil through the engine
- Purging fuel lines of air
Correct answer: Clearing exhaust gases and filling the cylinder with fresh air
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?
- To reduce fuel sulfur content
- To compress air supplied to the engine to increase power output (Correct answer)
- To cool the lubricating oil
- To control engine speed automatically
Correct answer: To compress air supplied to the engine to increase power output
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.
Question 6: Which regulation under STCW requires engineers to hold a valid medical fitness certificate?
- Regulation II/1
- Regulation VI/6
- Regulation I/9 (Correct answer)
- Regulation III/1
Correct answer: Regulation I/9
STCW Regulation I/9 sets the medical fitness standards that all seafarers, including engineers, must meet to serve on seagoing vessels.
Question 7: What is the primary hazard when opening a hot pressurized fuel oil system component?
- Electrical shock
- Hydrocarbon flash fire or scalding from pressurized hot oil spray (Correct answer)
- Carbon monoxide poisoning
- Nitrogen narcosis
Correct answer: Hydrocarbon flash fire or scalding from pressurized hot oil spray
Hot pressurized fuel oil released suddenly can flash into a mist that ignites immediately, or cause severe burns from scalding oil spray.
STCW Marine Engineering 2
What is the purpose of a jacket water cooling system on a marine diesel engine?