Boat maintenance log: what to record and why it matters

What a good entry contains

• Date and, for engines, hour meter reading
• The component or system involved
• A short description of the work performed
• Parts and fluids used, with quantities and specifications
• Who performed the work — owner, crew or a named yard
• Cost, and a link to the invoice or receipt
• Photos of the before and after state

The categories worth tracking separately

Grouping entries makes patterns visible. Over three seasons you will see which system consumes your budget and which one keeps surprising you.

• Engine and drivetrain — oil, filters, impellers, belts, alignment
• Hull and underwater — antifouling, anodes, propeller, seacocks
• Rig and sails — standing rigging, running rigging, sail repairs
• Electrical — batteries, charging, wiring, navigation electronics
• Plumbing and tanks — fresh water, holding tank, bilge pumps
• Safety — liferaft service, flares, extinguishers, EPIRB battery
• Interior and comfort — heater, upholstery, refrigeration

How often should you write in it?

Every time you touch a tool, plus three fixed moments each year: fitting out in spring, a mid-season check, and winterisation. Those three anchor points catch everything the ad-hoc entries miss.

Why it matters beyond tidiness

• Safety: expiry dates and inspection intervals stop being guesswork.
• Cost control: you see the true annual cost of ownership, not a vague feeling.
• Diagnostics: recurring symptoms become obvious when the history is in one list.
• Insurance: documented maintenance supports a claim rather than weakening it.
• Resale: a buyer pays more for a boat whose history is provable.

Paper, spreadsheet or app?

Paper is pleasant and fragile. A spreadsheet is better, but it does not remind you, does not hold photos well, and lives on one computer. A dedicated digital service book adds the three things that actually change behaviour: it is in your pocket at the boat, it reminds you before the deadline, and it survives the boat changing owners.