Rating Examination Practice Questions

Coast Guard Qualified Member of the Engine Department (QMED) – Any Rating Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which of the following is the primary function of a marine boiler?
• Provide potable water
• Produce steam for propulsion or auxiliary purposes
• Store fuel
• Generate electricity

Rationale: The main purpose of a marine boiler is to produce steam,

which can be used for propulsion or auxiliary machinery. 1 / 4

• What type of valve is commonly used to prevent backflow in a pump

discharge line?

• Globe valve
• Gate valve
• Check valve
• Butterfly valve

Rationale: Check valves allow flow in only one direction, preventing

backflow in pump discharge systems.

• What is the purpose of a bilge alarm?
• Measure fuel consumption
• Alert crew of high water levels in the bilge
• Monitor engine temperature
• Control pump operation

Rationale: Bilge alarms detect excessive water accumulation and

alert personnel to prevent flooding.

• Which of the following is considered a hazard of lubricating oil mist in

an engine room?

• Freezing
• Fire and explosion
• Corrosion
• Electrical interference

Rationale: Oil mist in confined spaces is highly flammable and poses

a serious fire or explosion hazard. 2 / 4

• What is the main purpose of a gland sealing system on a propeller

shaft?

• Lubricate bearings
• Prevent seawater from entering the ship
• Reduce vibration
• Increase propulsion efficiency

Rationale: Gland seals maintain a watertight seal around the shaft

where it passes through the hull.

• Which of the following is a characteristic of a centrifugal pump?
• Constant flow regardless of head
• Positive displacement
• Flow rate varies with head
• Uses reciprocating motion

Rationale: Centrifugal pumps are dynamic pumps where flow varies

with pressure (head). They are not positive displacement pumps.

• Which of the following is an indication of cavitation in a pump?
• Decreased temperature
• Noise and vibration
• Increased pressure
• Lubrication failure

Rationale: Cavitation causes bubbles that collapse violently,

producing noise, vibration, and potential damage to pump components. 3 / 4

• The main advantage of a diesel engine over a gasoline engine in

marine applications is:

• Higher speed
• Lighter weight
• Better fuel efficiency and reliability
• Easier starting

Rationale: Diesel engines are preferred on ships due to superior

efficiency, torque, and reliability for heavy-duty operation.

• In a typical marine diesel engine, what is the function of the governor?
• Lubricate the engine
• Regulate engine speed
• Cool the engine
• Inject fuel

Rationale: The governor maintains engine speed by adjusting fuel

injection based on load conditions.

• What is the purpose of a sea chest on a ship?
• Fuel storage
• Intake of seawater for cooling and firefighting systems
• Waste collection
• Crew access to the hull

Rationale: Sea chests serve as protected intakes for seawater used in

cooling, firefighting, and ballast systems.

• / 4