Watchkeeping is the core of an operational-level engineer's job and, not coincidentally, the source of a large proportion of oral examination questions. A surveyor asking how you take over a watch is asking whether you understand the job, not whether you have memorised a procedure.

Taking over the watch

You do not take over until you are satisfied. That is the principle, and it is examinable. In practice:

• Standing orders and the chief engineer's night orders, read and understood
• The log — what has changed since the last entry, and any work in progress
• Machinery in use and on standby, and any equipment out of service
• Any alarms that have operated, and whether any are inhibited or overridden
• Bilge and tank levels, and any transfer under way
• A round of the space before accepting, not after

If the relieving engineer is not fit to take the watch — fatigue, illness, or under the influence — the watch is not handed over. This comes up in orals and the expected answer is unambiguous.

The round

Instruments tell you what is being measured. A round tells you what is not. What you are looking for:

• Leaks — oil, fuel, water, steam, air. Fresh leakage against old staining.
• Sound — a change in note from a pump, a knock, a new whine from a turbocharger.
• Smell — hot oil, burning insulation, exhaust in the space.
• Temperature by hand where it is safe — bearings, casings, pipework against its neighbours.
• Vibration — anything that was not vibrating yesterday.
• Levels and drains — sump, header tanks, air receiver drains, scavenge drains.

A frequently asked question is what you would find on a round that no instrument would tell you. The answer is most of the above — a small fuel leak onto a hot surface has no sensor and is how engine room fires start.

Alarms, and why you do not rely on them

An alarm tells you a parameter has crossed a threshold. It does not tell you the plant is healthy below that threshold, and a developing fault spends most of its life below it. Trending is what catches the deterioration; the alarm catches what the trending missed.

Three specific arrangements come up constantly:

• Oil mist detection — the response, the cooling period, and why the crankcase is not opened
• Scavenge space temperature — the warning of an incipient scavenge fire
• The dead man alarm — its purpose during unattended operation and how it escalates

Unattended machinery space operation

UMS does not mean the space looks after itself. It means the alarm and monitoring system substitutes for a watchkeeper, and that substitution is only valid if the system has been proved. Before an unattended period, the checklist covers standby machinery, alarm testing, bilge levels, fire detection and the engineer's call system.

Signing that checklist without performing it is the failure mode that precedes most serious UMS incidents — a point worth making explicitly if asked, because it demonstrates you understand what the checklist is for.

Handing over

The reverse of taking over, and the part most often done badly. State what changed, what is in progress, what you are watching and why, and what you would want to be called for. A handover that consists of "all normal" transfers no information at all.

Why this is examined so heavily

Because it is the job. An engineer who can describe a round in specific sensory terms, explain what they would do about what they found, and articulate what they would not take over — has demonstrated more than any amount of recited theory.