Maintenance and Repair
What this domain tests
Planned maintenance, condition monitoring, defect reporting, spares control, dry-docking and repair specification, and the chief engineer's role as the person who signs off work. Expect questions on why a planned maintenance system beats breakdown maintenance, how to write a repair specification, and what is reviewed before a surveyor at dry dock.
Core rules and concepts
- PMS and ISM. The ISM Code requires maintenance procedures and records; the PMS schedules tasks by running hours and calendar, records completion, and feeds defects into a work-order system. Non-conformities and their close-out are examined.
- Condition monitoring. Vibration analysis, oil analysis (spectrometry, water, TAN/TBN, insolubles), thermography, cylinder liner wear measurement, and trend analysis. Trend matters more than a single reading.
- Defect and risk management. Critical spares list, minimum stock, lead times, and the risk assessment before running a degraded machine. Running to the next port with a defect requires documented risk assessment and the company's acceptance.
- Dry-docking. Repair specification, tender to yards, work scope, class survey items, thickness measurement, tank cleaning and gas-free certification, hot work permits, chain and anchor inspection, sea valves, and the final acceptance with running trials and class documentation.
- Workshop practice interface. Tolerances, alignment, bolting torque, fits and clearances, machining marks, and the sign-off of dimensions against the maker's manual.
- Records. Maintenance records, engine room log, oil record book, and the technical file for any modification requiring class approval.
Worked example
A main engine exhaust valve is found cracked at the seat during overhaul, 2,000 hours before the scheduled replacement. Reasoning: this is a condition-based replacement, not a schedule change; the spare must be fitted with correct clearances and the remaining units inspected. Action: replace the valve, inspect the other units, record the finding, raise a defect, review the running hours to see whether the maker's recommendation should change, and adjust spares stock. The scoring answer distinguishes correcting the defect from changing the maintenance policy without the maker's agreement.
Traps that cost marks
- Treating PMS as paperwork rather than a control system.
- Reporting a defect without a risk assessment when continuing to run.
- Missing the class survey items in a dry-docking answer.
- Changing maintenance intervals without maker/class agreement.
- Forgetting to record and close out the finding.