Maritime and Marine Marine Engineering and Propulsion

Question 1

What does the term 'cavitation' mean in marine propulsion?

Accepted Answer

Formation and collapse of vapor bubbles on the propeller blades causing erosion and loss of thrust

Answer

Vibration caused by propeller blade imbalance during high-speed operation

Answer

Air entrainment in the fuel system causing engine performance loss

Answer

Overheating of the propeller shaft bearing during extended operation

Question 2

What is the function of a heat exchanger on a marine engine?

Accepted Answer

To cool the engine's freshwater coolant using raw seawater without mixing the two circuits

Answer

To heat fuel before injection for better combustion in cold weather

Answer

To transfer heat from the exhaust to the air intake system

Answer

To warm seawater before it enters the engine cooling jackets

Question 3

What is the purpose of zinc anodes (sacrificial anodes) on a vessel's underwater hardware?

Accepted Answer

To protect metal fittings from galvanic corrosion by being sacrificially corroded instead

Answer

To add weight for ballast and improve vessel stability

Answer

To reduce drag by creating a smooth surface on the hull

Answer

To conduct static electricity away from electronic equipment

Question 4

What does a two-stroke outboard engine require that a four-stroke engine does not?

Accepted Answer

Oil premixed with the fuel or injected by a separate oil injection system

Answer

Regular valve adjustments for proper engine timing

Answer

A separate crankcase oil reservoir and oil changes

Answer

A carburetor heat system to prevent icing

Question 5

What is the function of a seacock (sea valve) on a vessel?

Accepted Answer

To shut off a through-hull fitting to prevent flooding if a hose or fitting fails

Answer

To control the flow of cooling water to the engine

Answer

To regulate ballast water intake for stability adjustment

Answer

To drain the bilge overboard when the vessel is at rest

Question 6

What does 'shaft horsepower' (SHP) measure in marine engineering?

Accepted Answer

Power actually delivered to the propeller shaft, after accounting for engine and gear losses

Answer

Gross engine output power before any mechanical losses

Answer

Power required to push a vessel at its maximum hull speed

Answer

The combined output of all engines on a multi-engine vessel