A useful log proves what happened and shows change over time. Use one record for each engine, drive and generator.
| Field | Record |
|---|---|
| Equipment | Make, model, serial, rated power and rpm |
| Event | Date, engine hours and location |
| Work | Exact task and person or business completing it |
| Parts | Manufacturer and part number |
| Fluids | Product, grade, quantity and batch if relevant |
| Findings | Leaks, debris, wear, colour, measurements and photos |
| Test | Cranking volts, charging, temperature, pressure, rpm and load |
| Next due | Date and engine-hour limit |
Attach invoices, oil reports, coolant tests, fault-code printouts, alignment readings and commissioning sheets. Note whether an impeller came out complete, whether a filter contained water and how much an anode had wasted.
For saildrives, retain dated evidence of diaphragm replacement, pressure tests, coating system and anode type. For shaft drives, retain seal, bearing, alignment and propeller records. For generators, record electrical load during testing, not merely running hours.
When selling, organised records reduce uncertainty. When troubleshooting, they reveal exactly which filter, coolant or wiring change preceded the problem.