How to Keep a Boat Maintenance Log and Organize Your Receipts

• Paper notebook or binder: cheap, works without signal or battery, and easy to hand to a buyer. Boating Magazine suggests plain lined pages so you are not boxed into preset categories.
• Spreadsheet: easy to sort by date or system, and easy to back up.
• App: many boat, engine-maker and general maintenance apps can store entries, reminders and photos. Check that you can export your records (PDF or spreadsheet) in case the app goes away or you sell the boat.

Many owners keep a small notebook aboard for quick notes and copy them into a spreadsheet or app at home.

On the first page, list:

• Hull identification number (HIN), registration or documentation number, make, model and year.
• Engine make, model and serial numbers (each engine, plus generator and outdrive or gearcase if separate).
• Purchase date and the engine hours at purchase.
• Warranty start and end dates.
• Insurance company and policy number.

You will look these up constantly.

Boating Magazine recommends keeping two or three pages at the back for part numbers and specs you buy again and again:

• Filters, spark plugs, impellers, anodes, belts and O-rings.
• Fuse and breaker types and ratings, and light bulb types.
• The ignition key number.

Tape in or photograph the labels from parts boxes. Copy numbers from your owner's manual or parts receipts; never guess.

Each time anyone works on the boat, write:

• Date.
• Engine hours from the hour meter (each engine if you have twins).
• What was done: inspected, cleaned, adjusted, replaced, and on which system or side.
• Parts and fluids used: brand, part number, quantity.
• Who did it: you, or the shop's name, address and phone.
• Cost: parts and labor.
• Notes: what you found, such as "impeller vanes cracked" or "light corrosion on battery terminal".

Boating Magazine advises writing clearly enough that a future owner can read it, and logging everything, no matter how small.

Most engine makers set service by hours or time, whichever comes first. For example, Yamaha lists a first service at 20 hours for new outboards, then every 100 hours or once a year, with a fuel/water separator filter every 50 hours; confirm your own schedule in your manual. Write each service with the hours, then note when the next one is due, such as "Next: 200 hrs or June 2027".

Battery swaps, blown fuses, a steering cable, a new bilge pump, a strange noise or a warning alarm all go in the log, even if you fixed them in five minutes. These entries are what reveal patterns later. Write symptoms with the date and hours even before you know the cause.

Boating Magazine suggests logging fuel purchases with engine hours, because fuel burned per hour is a good gauge of engine health. A slow rise in fuel use at the same speeds can point to a fouled bottom, a damaged prop or an engine problem.

Log the date you add electronics, batteries, a trolling motor, canvas or anything else, with the cost and serial number. It helps with insurance (proof of what was aboard) and with resale (what the boat comes with).

Photograph the job: the old part next to the new one, hose and wire routing before you take things apart, and the hour meter on service day. Name the photos with the date and the job, such as "2026-10-25 impeller", and store them with the log. Photos also help a lot after an accident or storm.

The FTC's general rule under the federal Magnuson-Moss Warranty Act is that a company generally cannot require you to use its brand of parts or its service to keep a warranty, unless it provides them free or gets an FTC waiver. Doing your own maintenance can be fine, but you need proof that it was done on schedule with the right parts. Keep parts receipts, shop invoices and fluid receipts. Good ways to organize:

• An accordion folder with one pocket per year, or one per system (engine, electrical, hull, trailer).
• Snap a photo or scan of each receipt the day you get it. Thermal paper fades.
• Write the engine hours and the log page number on each receipt.

Check your own warranty booklet for its exact maintenance and record-keeping terms.

Store owner's manuals, warranty statements, registration copies and survey reports in the same place. Boating Magazine suggests keeping manuals and receipts together so they can go to the next owner. Yamaha notes that if you pay for a repair abroad that you think warranty should have covered, you need to bring repair orders and receipts to your dealer at home.

Buying or selling? Log the warranty transfer. Remaining factory coverage usually doesn't follow the engine by itself. Mercury, for example, transfers the rest of its limited warranty when it gets a copy of the bill of sale with the engine serial number and sale date plus the new owner's details. It may ask for a paid dealer inspection first, and can refuse engines bought at auction, from a salvage yard or from an insurance company. A Yamaha blog post describes a dealer inspection and transfer for its outboards too. File the bill of sale, the transfer confirmation and the inspection report with your log, and note the date and engine hours.

Boats flood, burn and get stolen, so a log kept only aboard can be lost with the boat. Keep a copy at home or in cloud storage, and photograph the paper log pages after each season.

At commissioning and at layup, read the past year's entries:

• What is due soon?
• What keeps coming back?
• What did you spend?

Use it to plan your next season's work and budget. Before a survey, insurance renewal or sale, print a short summary of major work with dates, hours and costs.