Oceans Examination Practice Questions

Coast Guard Chief Engineer (Limited Oceans) Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a main engine jacket water system?
• Lubricate cylinder walls
• Reduce combustion temperatures
• Cool engine components **
• Prevent air contamination

Correct Answer: C

Rationale: The jacket water system removes excess heat from engine

components, maintaining proper operating temperature.

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• Which device is used to remove entrained air from a hydronic cooling

system?

• Centrifugal purifier
• Air separator
• Check valve
• Priming pump

Correct Answer: B

Rationale: Air separators collect and vent trapped air to maintain efficient

heat transfer and flow.

• In a lube oil system, what is the purpose of a duplex strainer?
• Heat the oil
• Control pressure
• Allow cleaning one strainer while the other remains online
• Remove water

Correct Answer: C

Rationale: Duplex strainers ensure continuous filtration without shutting

down equipment.

• A bilge high-level alarm must activate when the bilge reaches which

condition? 2 / 4

• Bilge is dry
• Bilge pump is running
• Water rises to a preset unsafe level
• Vessel is underway

Correct Answer: C

Rationale: High-level alarms protect against flooding and ensure timely

pumping.

• Which refrigeration component changes refrigerant vapor to liquid?
• Compressor
• Evaporator
• Receiver
• Condenser

Correct Answer: D

Rationale: The condenser rejects heat and condenses high-pressure vapor

into a liquid.

• What is the major advantage of a four-stroke diesel engine?
• Twice as many power strokes
• Uses less air
• Cleaner combustion and better efficiency
• Heavier construction 3 / 4

Correct Answer: C

Rationale: Four-stroke engines offer improved fuel efficiency and reduced

emissions.

7. The primary purpose of an aftercooler on a diesel engine is to:

• Lubricate pistons
• Reduce charge-air temperature
• Increase exhaust temperature
• Cool lube oil

Correct Answer: B

Rationale: Cooling air increases density and improves combustion

efficiency.

• Which pump type is MOST commonly used for bilge pumping?
• Reciprocating pump
• Axial flow pump
• Centrifugal pump
• Gear pump

Correct Answer: C

Rationale: Centrifugal pumps handle high-volume, low-viscosity liquids like

bilge water.

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