100+ Free GMA CoC EOOW Practice Questions

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2026 Statistics

Key Facts: GMA CoC EOOW Exam

STCW III/1

Regulation Standard

IMO

50%

Passing Score

GMA Guidelines

12 mos

Minimum Sea Service

With RMU Cadetship

5 years

CoC Validity

STCW Revalidation

Quarterly

Exam Sittings

GMA Schedule

RMU

Training Institution

Accra, Ghana

The GMA Engineer Officer of the Watch (EOOW) Certificate of Competency is Ghana's official certification for marine engineering watchkeeping officers under STCW Regulation III/1. It requires completing approved training (such as upgrading courses at RMU), fulfilling 12 months of approved seagoing service, passing written subject exams (with a 50% pass mark), and passing an oral board exam. This free practice portal offers 100 questions covering diesel engine propulsion, electrical grids, maintenance protocols, and maritime safety regulations.

Sample GMA CoC EOOW Practice Questions

Try these sample questions to test your GMA CoC EOOW exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the primary cause of a scavenge space fire in a large two-stroke crosshead marine diesel engine?

A.Accumulation of unburnt cylinder oil and carbonaceous deposits ignited by blow-by of hot combustion gases.

B.Excessive fuel injection pressure causing cylinder overload.

C.Failure of the piston rod stuffing box gland seals allowing crankcase oil to enter.

D.High exhaust gas backpressure due to a fouled turbocharger nozzle ring.

Explanation: Scavenge fires occur when unburnt lubricating oil, fuel residue, and carbon deposits accumulate in the scavenge space and are ignited. Ignition is typically caused by blow-by, where worn or broken piston rings allow hot combustion gases to blow past the piston into the scavenge trunk. Maintaining piston ring sealing and regularly cleaning scavenge ports are critical preventative measures.

2What is the immediate action to take if a scavenge space fire is detected in a running main propulsion diesel engine?

A.Slow down the engine, cut off fuel to the affected cylinder(s), close the scavenge air drains, and inject extinguishing medium (such as CO2 or steam).

B.Stop the engine immediately and open all crankcase inspection doors to check for overheating.

C.Increase engine speed to blow the carbon deposits out through the exhaust gas receiver.

D.Open the scavenge air drains fully to drain the accumulating lube oil and relieve pressure.

Explanation: The immediate action for a scavenge fire is to reduce engine speed to limit the supply of scavenge air, cut off fuel to the cylinder(s) above the fire, close the scavenge drains to isolate the fire, and inject the designated extinguishing medium (steam, CO2, or water mist). Stopping the engine immediately without reducing thermal stress can cause major damage, and opening crankcase doors is dangerous due to the risk of air ingress causing a crankcase explosion.

3Why must you wait at least 20 to 30 minutes after a main diesel engine has stopped due to suspected hot spot before opening crankcase doors?

A.To allow the hot spot to cool below the ignition temperature of the oil mist, preventing a catastrophic explosion from air ingress.

B.To allow the lube oil pump to scavenge all remaining oil from the crankcase sump.

C.To allow the starting air pressure in the air receivers to bleed down to safe levels.

D.To allow the cylinder liners to cool evenly, preventing thermal cracking of the engine frame.

Explanation: A hot spot in the crankcase (e.g., an overheated bearing or piston skirt) can vaporize lube oil, creating a highly explosive oil mist. If the crankcase doors are opened while the hot spot is still hot, the sudden influx of fresh air provides the necessary oxygen to trigger a violent crankcase explosion. Waiting at least 20-30 minutes allows the hot spot to cool down safely below the ignition threshold.

4What is the function of a crankcase oil mist detector (OMD) on a marine diesel engine?

A.To detect concentration of oil mist in the crankcase and warn of developing hot spots before an explosion can occur.

B.To measure the oil level in the main sump tank automatically.

C.To monitor the viscosity and water content of the lubricating oil during engine operation.

D.To control the rate of cylinder oil injection based on engine load.

Explanation: An oil mist detector continuously samples the crankcase atmosphere of each cylinder unit. If an internal component (like a main bearing) overheats, it vaporizes lube oil into a fine mist, which increases the opacity of the crankcase air sample. The OMD detects this change optically and triggers an alarm/slowdown to prevent a crankcase explosion.

5In a diesel engine indicator diagram, what does a low compression pressure coupled with a low maximum combustion pressure generally indicate?

A.Leaking piston rings, worn cylinder liners, or leaking exhaust valves.

B.Late fuel injection timing or fouled fuel injectors.

C.Excessive fuel injection pump delivery or high fuel index.

D.Early fuel injection timing causing pre-ignition.

Explanation: Compression pressure depends on the mechanical seal of the combustion chamber. If piston rings are leaking (blow-by), cylinder liners are severely worn, or exhaust valves are not sealing properly, air escapes during the compression stroke. This results in low compression pressure, which consequently leads to low peak combustion pressure since there is less air mass and pressure at the start of ignition.

6What is the primary indicator of late fuel injection timing when analyzing a diesel engine's performance?

A.High exhaust gas temperatures, black smoke, and low peak combustion pressure on the indicator card.

B.Unusually high peak combustion pressure (Pmax) and low exhaust gas temperatures.

C.Sudden engine overspeed and rapid cooling of the jacket water system.

D.Low exhaust gas temperatures and high fuel economy.

Explanation: If fuel injection is timed too late, combustion continues during the expansion stroke rather than finishing near Top Dead Center (TDC). This results in lower peak combustion pressure (since the cylinder volume is already increasing) and causes high exhaust temperatures because the fuel is still burning as the exhaust valve opens, often accompanied by black smoke due to incomplete combustion.

7What damage can occur if a diesel engine starting air valve leaks during normal engine operation?

A.Hot combustion gases can blow back into the starting air line, potentially igniting oil deposits and causing a starting air line explosion.

B.The cylinder will suffer from high oil pressure and blown cylinder head gaskets.

C.The turbocharger will surge and blow black smoke through the air intake filters.

D.The starting air receivers will drain completely through the engine exhaust system.

Explanation: A leaking cylinder starting air valve allows high-temperature combustion gases to enter the starting air manifold. If there are lubricating oil deposits inside the starting air lines (from air compressor carryover), the hot gases can ignite these deposits. This can trigger a starting air line explosion, which is why safety non-return valves, relief valves, and bursting discs are fitted to starting air manifolds.

8What is the purpose of the indicator valve fitted to each cylinder cover of a marine diesel engine?

A.To connect an indicator instrument for pressure measurements, and to blow out moisture or soot before starting the engine.

B.To relieve excess pressure in the cylinder during normal operation like a safety valve.

C.To inject starting air directly into the combustion chamber to roll the crankshaft.

D.To sample fuel oil directly from the injection nozzle during timing checks.

Explanation: The indicator valve provides access to the combustion chamber. It is used to connect indicator instruments (like mechanical indicators or electronic sensors) to draw power cards. Additionally, before starting an engine, the indicator valves are opened, and the engine is turned with starting air or on turning gear to blow out any accumulated water, fuel, or oil, preventing hydraulic lock.

9What is the main design difference between a trunk-type and a crosshead-type diesel engine?

A.In trunk-type engines, the gudgeon pin connects the piston directly to the connecting rod; in crosshead engines, a piston rod connects to a crosshead guide which joins the connecting rod.

B.Trunk-type engines are exclusively two-stroke, while crosshead engines are exclusively four-stroke.

C.Trunk-type engines utilize starting air, whereas crosshead engines are started exclusively by an electric motor.

D.Trunk-type engines use heavy fuel oil, whereas crosshead engines can only burn high-grade marine gas oil.

Explanation: In trunk-type engines (typically medium/high-speed), the piston skirt absorbs the side thrust from the angled connecting rod. In crosshead engines (typically large, slow-speed two-stroke), the piston rod moves in a purely vertical linear motion, and the lateral thrust is absorbed by the crosshead guides and slippers, allowing the crankcase to be sealed off from the cylinder space by a diaphragm and stuffing box.

10What is the function of the piston rod stuffing box in a crosshead-type marine diesel engine?

A.To prevent combustion products and cylinder oil from entering the crankcase, and to scrape crankcase oil from the piston rod.

B.To guide the vertical motion of the crosshead slipper in the engine frame.

C.To lubricate the piston rings with high-pressure cylinder oil.

D.To seal starting air within the piston cooling spaces during engine starting.

Explanation: The piston rod stuffing box is mounted in the diaphragm plate separating the under-piston space from the crankcase. It contains scraper rings that scrape lubricating oil off the piston rod back into the crankcase, and sealing rings that prevent dirty cylinder oil and combustion soot from draining down and contaminating the crankcase lube oil system.

About the GMA CoC EOOW Exam

The Ghana Maritime Authority (GMA) Certificate of Competency (CoC) for Engineer Officer of the Watch (EOOW) is the official credential for watchkeeping marine engineering officers in Ghana. Aligned with STCW Regulation III/1, this certification qualifies candidates to take charge of an engineering watch in a manned engine room or act as the designated duty engineer in a periodically unmanned engine room on ships powered by main propulsion machinery of 750 kW propulsion power or more.

Assessment

Multiple subject-specific written examinations covering engineering, electrical systems, maintenance, and safety, followed by a professional oral exam conducted by a GMA examiner.

Time Limit

Varies by subject paper (typically 2-3 hours each)

Passing Score

50% per subject area

Exam Fee

Varies (Refer to GMA Schedule of Fees) (Ghana Maritime Authority (GMA))

GMA CoC EOOW Exam Content Outline

40%

Marine Engineering

Diesel propulsion, marine boilers, auxiliary machinery, steering systems, and piping.

20%

Electrical, Electronic and Control Engineering

Alternators, distribution systems, instrumentation, automation, and control loops.

20%

Maintenance and Repair

Safe maintenance practices, machine tool operations, troubleshooting, and component overhauls.

20%

Controlling Ship Operations and Safety

STCW watchkeeping duties, MARPOL, ship construction/stability, SOLAS, firefighting, and lifesaving.

How to Pass the GMA CoC EOOW Exam

What You Need to Know

Passing score: 50% per subject area
Assessment: Multiple subject-specific written examinations covering engineering, electrical systems, maintenance, and safety, followed by a professional oral exam conducted by a GMA examiner.
Time limit: Varies by subject paper (typically 2-3 hours each)
Exam fee: Varies (Refer to GMA Schedule of Fees)

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

GMA CoC EOOW Study Tips from Top Performers

1Master main engine watchkeeping procedures, including emergency response to scavenge fires, crankcase explosions, and boiler water loss.

2Understand the principles of electrical synchronization, alternator protection devices, and emergency switchboard operations.

3Focus on the practical operation and troubleshooting of auxiliary systems such as centrifugal purifiers, oily water separators, and steering gear.

4Practice drawing block diagrams of fuel oil, lube oil, cooling water, and bilge piping systems.

5Memorize MARPOL Annex regulations, particularly Annex I (oil pollution) and discharge limits (e.g., 15 ppm threshold).

Frequently Asked Questions

What is the Ghana Maritime Authority EOOW CoC?

The Engineer Officer of the Watch (EOOW) Certificate of Competency (CoC) is a professional qualification issued by the Ghana Maritime Authority (GMA) under STCW Regulation III/1. It certifies that a seafarer is competent to serve as a watchkeeping engineer officer in a ship's engine room.

Where do candidates train for the GMA EOOW exam?

Approved maritime training is typically completed at the Regional Maritime University (RMU) in Accra, Ghana, which is the primary approved Maritime Education and Training Institution (METI) in the country.

What is the passing score for the GMA EOOW written exams?

The written examinations administered under the Ghana Maritime Authority and RMU guidelines generally require a minimum score of 50% in each subject area to pass, in addition to passing the oral exam conducted by a GMA examiner.

What topics are covered in the GMA EOOW CoC examination?

The syllabus aligns with STCW Table A-III/1 and is divided into four main functions: Marine Engineering (40%), Electrical, Electronic & Control Engineering (20%), Maintenance & Repair (20%), and Controlling Ship Operations & Safety (20%).

How do I apply for the GMA EOOW exam and certification?

Candidates must verify their sea-going service and training eligibility, book an appointment through the Ghana Maritime Authority Appointment Portal, pay the required fees, and submit their application in person at the GMA office.