Marine Engine Operation and Watchkeeping
What the exam tests
This domain tests whether you can run a local vessel's engine safely through a full watch: pre-start checks, monitoring, fault response, handover and records. Questions often use a short scenario rather than a component diagram, so link each action to a measurable parameter and a consequence.
Core routines
- Before start: check fuel and lube-oil levels, coolant, raw-water strainer, battery isolation, sea suction, gearbox oil, belts and guards. Confirm that no one is working on the engine and that the fuel shut-off and emergency stop are accessible.
- During watch: compare readings with normal values, not only alarm limits. Typical items are lube-oil pressure, coolant temperature, exhaust temperature, raw-water flow, fuel pressure, charging voltage and unusual noise or vibration.
- Every log entry should be timed and signed; record changes, not only steady values.
- Handover: give current status, defects, ongoing work, fuel state and any isolation. Do not hand over a running engine with an unresolved alarm without telling the relief and the person in charge.
Worked example
A sea-water-cooled engine runs and the coolant temperature climbs slowly from 82°C to 95°C while lube-oil pressure stays normal. The raw-water overboard flow is weak and the strainer differential is high. Reasoning: normal oil pressure and a high strainer differential point to raw-water starvation, not bearing failure. Reduce load, stop the engine if temperature continues to rise, close the sea suction, clean the strainer, verify flow, then restart and watch. Log the action and report the defect.
Traps
- Resetting an alarm without finding the cause.
- Assuming low lube-oil pressure is a gauge fault; stop and investigate.
- Running with a known raw-water leak or blocked strainer because 'it was fine yesterday'.
- Handing over orally only, with no log entry.
- Loading a cold engine before oil pressure is established.