Boat Maintenance Log: A Template, Example Entries and How to Keep It Up

Do you legally need a maintenance log?

For most privately used pleasure boats, no law requires a maintenance log. Commercially operated vessels are a different matter: charter boats, passenger boats and workboats usually come under inspection and record-keeping rules set by the flag authority, depending on the vessel's category and use, so check with your flag state or maritime authority. Two practical reasons make a log close to essential anyway. Engine warranties come first: many engine makers' warranty terms expect proof that servicing followed their schedule, so read the terms for your own engines. Surveys and sales come second: a surveyor or buyer judges upkeep on evidence, not on your word. A maintenance log is also not the ship's log. The ship's log records passages: dates, routes, weather, crew and incidents. The maintenance log records what was done to the boat. Keep them separate.

The boat maintenance log template: sections by system

Organize the log by system, not just by date. When a surveyor asks for the engine history, you should find it without reading three years of hull entries. Start with an identity page, then open one section per system. Every entry in every section follows the same format, shown at the end of this list.

• Boat identity: name, registration, hull identification number (HIN/CIN), builder, model, year, length; for each engine and generator: make, model, serial number, position and date in service.
• Engines and drivetrain: oil and filters (oil, fuel, air), raw-water impeller, belts, cooling circuit, engine anodes, gearbox or leg oil, saildrive diaphragm, exhaust elbow.
• Hull and underwater: lift-out (haul-out) and antifouling, anodes, through-hulls and seacocks, propeller, shaft and stern gland or shaft seal, rudder.
• Electrical: batteries (fitting date, test results), charger, alternator, switch panel, connections, galvanic isolation.
• Safety gear: extinguishers, life raft, EPIRB and its hydrostatic release, flares, lifejackets and re-arming kits, first-aid kit, each with its expiry or service date.
• Electronics and rig (sailing boats): instruments, VHF (and MMSI), autopilot; standing rigging, bottle screws (turnbuckles), sails, date of the last mast inspection.
• Format for every entry: date, engine hours, work done, who did it, parts (part numbers and quantities), cost, receipt or photo.

Three example entries (fictional)

These entries are invented for illustration, on an 11 m sailing yacht with an inboard diesel and a saildrive. They show the level of detail that makes a log useful: each one records the hour meter, what was fitted and where the proof is kept.

• 12 Mar 2026, 1,184 h, engine: oil and oil filter changed, primary and secondary fuel filters replaced, belt checked. Done by the yard (technician named on the invoice). Parts: oil to the required spec, three filters (part numbers noted). Cost: see invoice 318. Photo of the old primary filter.
• 4 Apr 2026, 1,186 h, hull: lift-out, hull cleaned, two coats of antifouling, saildrive and propeller anodes replaced, seacocks exercised. Done by the yard. Before and after photos of the hull, invoice attached.
• 20 May 2026, 1,201 h, safety: saloon extinguisher replaced (out of date), new set of flares (expiry date noted), first-aid kit restocked. Done by the owner. Receipts attached.

How often to update the log

One entry per job, on the day, by the person who did the work or had it done. Two clocks run side by side. Some jobs follow the calendar: antifouling, the annual service, safety-gear dates. Most engine work follows running hours, which is why every entry carries the hour-meter reading. When a manufacturer gives both an hours figure and a time limit, whichever comes first triggers the service. The intervals themselves come from the engine maker's manual and the equipment manuals, not from a generic table found online: they vary with the model and with how hard the boat is used.

• Every job: a dated entry with engine hours.
• Every trip, or weekly in season: note the hour meter even when nothing was done, so you can see services coming.
• Start of season: check safety-gear dates and the recommendations left on the last service reports.
• End of season: review everything before laying up and list what will be due.

Gear that expires: keep a separate calendar

Some equipment has a deadline that has nothing to do with engine hours, and it is the one people forget because it never makes a noise. What you must carry depends on the boat, its use and where it sails, and the dates come from each manufacturer. Keep them all in one place and note when you need to act, not just the expiry date: a life raft has to go to an approved service station, and that needs booking ahead.

• Flares: expiry date printed on each one.
• Fire extinguishers: service or replacement date.
• Life raft: next service date.
• EPIRB: battery and hydrostatic release dates.
• Auto-inflating lifejackets: gas cylinder and firing mechanism.
• First-aid kit: medicines and consumables.
• Certificates and inspections: for example a Boat Safety Scheme certificate if you cruise UK inland waterways.

Paper, spreadsheet or app?

The best format is the one you will keep current. For one boat and one careful owner, a spreadsheet is often enough. Once several people work on several boats, a shared tool stops the gaps from opening up in the history.

• Paper logbook: no kit needed, always aboard. Weak points: it gets wet, it gets lost, it can't be searched, and the receipts live somewhere else.
• Spreadsheet: free, easy to sort by system or by date. Weak points: no reminder when something is due, photos and receipts outside the file, rows overwritten by mistake.
• App: reminders before things fall due, photos and invoices attached to each entry, one history shared by owner, skipper and yard. Weak points: a subscription, some learning, and an export you should test so you are never locked in.

What a buyer, surveyor or insurer looks for

When a boat is sold, a careful buyer and their surveyor check three things: that log entries match invoices, that the hour meter is consistent with the history, and that the big wear items were dealt with on time. A log that answers those questions quickly shortens the conversation; a patchy one opens the negotiation. On the insurance side, some insurers ask for a condition and valuation survey on older or higher-value boats, and every policy has its own conditions. A documented history makes that survey smoother and supports a claim. Read your policy to see what it expects.

• Invoices filed in the same order as the log.
• Hour-meter readings that add up from one entry to the next, with a note if the meter was ever replaced.
• Dates for major work: repower, engine overhaul, new saildrive or rig, life-raft replacement.
• The latest survey report, and what was done about its findings.

Keeping the log on an owner's behalf

When a boat is looked after by a management company or a yard, the people doing the work keep the log, and the owner should be able to read it without asking. In Captain Crews, marine management software, every completed work order feeds the boat's maintenance tab, filed by category (engine, generator, electrical, hull, safety and so on), with time-stamped photos, parts fitted and invoices read by OCR. Each engine flags its next service as the hours approach, the safety register tracks expiry dates, and owners see jobs and invoices in their portal, on the web or in the iOS and Android apps. An existing spreadsheet log can be imported, and the history exported back to Excel.