Which of the following is NOT a common type of ship engine?

• A. Diesel
• B. Gas turbine
• C. Nuclear reactor
• D. Steam turbine

Answer: (C)

In ship propulsion, you typically see engines like diesel engines, gas turbines, and steam turbines because they are practical, widely supported, and can be operated on fuels and in ports around the world. A diesel engine is the workhorse for most commercial and many naval vessels due to efficiency and reliability. Gas turbines provide quick, high-power output for fast ships and modern warships, while steam turbines have powered many large ships in the past and still appear in certain situations.

A nuclear reactor, while extremely capable in terms of endurance and power, is not a common ship engine because it requires highly specialized technology, strict safety and regulatory frameworks, extensive shielding, trained personnel, and limited suitable ships. Only a small number of military vessels—like certain submarines and aircraft carriers—use nuclear propulsion, and civilian or general-merchant ships do not. That combination of complexity, cost, and regulatory hurdles makes nuclear propulsion not a common option for ships overall.