Oceans Examination Practice Questions

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

• Which device is used to automatically maintain a set steam pressure in a

boiler?

• Steam trap
• Feedwater regulator
• Pressure control valve
• Stop-check valve

Rationale: Pressure control valves modulate flow to maintain constant

steam pressure automatically.

• Fuel atomization in a diesel engine is primarily affected by: 1 / 4

• Jacket water temperature
• Injection pressure
• Air receiver pressure
• Crankcase pressure

Rationale: Higher injection pressure produces finer fuel atomization for

efficient combustion.

3. The primary purpose of a lube oil cooler is to:

• Heat the oil before filtration
• Maintain oil viscosity within operating range
• Remove fuel dilution
• Remove water contamination

Rationale: Proper cooling maintains viscosity required for lubrication and

protection.

4. A thrust bearing on a propulsion shaft primarily absorbs:

• Radial loads
• Axial loads
• Rotational vibration
• Lateral movement

Rationale: Thrust bearings absorb axial (forward–aft) loads produced by

the propeller.

• Which type of pump is typically used for bilge service? 2 / 4

• Reciprocating pump
• Screw pump
• Centrifugal pump
• Rotary gear pump

Rationale: Centrifugal pumps handle large volumes of relatively clean bilge

water effectively.

6. A purifier operating in “clarifier mode” removes:

• Oil and water
• Insoluble solids only
• Water only
• Fuel additives

Rationale: Clarifiers remove solids when the water outlet is sealed.

7. The purpose of a jacket water expansion tank is to:

• Collect lube oil leakage
• Allow thermal expansion and maintain system pressure
• Remove dissolved gases
• Improve heat transfer

Rationale: Expansion tanks prevent overpressure and ensure a positive

head to the cooling system.

8. Lube oil contamination with water is most easily detected by:

• Sounding tubes
• Viscometer 3 / 4

• Oil mist detector
• Crackle test

Rationale: The crackle test reveals water by popping when heated.

9. The main advantage of a controllable-pitch propeller is:

• Reduced maintenance
• Ability to change thrust without changing engine speed
• Lower fuel consumption
• Improved cooling

Rationale: CPP systems vary blade angle independently of engine RPM.

10. In a shell-and-tube heat exchanger, heat transfer is improved by:

• Increasing tube thickness
• Reducing coolant flow
• Increasing flow turbulence
• Using fewer tubes

Rationale: Turbulent flow increases heat transfer efficiency.

11. Generator voltage is controlled by adjusting the:

• Engine speed
• Field excitation
• Alternator size
• Load factor

Rationale: Excitation current directly regulates generator output voltage.

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