The hourly log entry is the oldest discipline in passage-making, and it has outlived every navigation technology that promised to replace it. This guide covers what a boat logbook should contain, why the habit still earns its keep, and the honest failure modes of the paper book most of us learned on.
Why keep a boat logbook at all?
Because the logbook is the only continuous record of judgment aboard. The chartplotter knows where you were; only the log knows why you altered course, when the barometer started falling, which sail you carried, and who was on watch when the wind backed. Four practical reasons the habit survives:
- Navigation fallback: if the electronics die, your last written position, course, and speed are what dead reckoning starts from
- Evidence: insurance claims, incident reports, and warranty disputes are won by contemporaneous written records
- Boat memory: engine hours, gear failures, and maintenance events, in sequence, with context
- The story: years later, the log is the passage — the squall, the landfall, the night the dolphins came
What should a boat logbook contain?
The classic column headings have been stable for a century because they answer the questions that matter later: date and time, position, course steered, speed over ground, wind speed and direction, sea state, barometer, engine hours when motoring, and remarks. The remarks column is where the real logbook lives — sail changes, watch changes, gear trouble, weather trend, anything you would want the next watch (or a future you) to know.
On passage, the rhythm is an entry every hour on the hour, plus one at every significant event. Day-sailing, an entry at departure, at each waypoint or condition change, and at arrival is plenty. The test is simple: could someone reconstruct your day from the log alone?
Where paper logbooks fail
We kept a beautiful paper log for years, so this is criticism from experience, not marketing. Paper fails offshore in four specific ways:
| Failure | How it bites |
|---|---|
| It gets wet | one dropped washboard, one wave down the companionway, and the record dissolves |
| It is a single copy | the log lives aboard, so anything that takes the boat takes the evidence with it |
| It cannot be searched | finding "the day the autopilot first acted up" means paging through months by hand |
| It tells shore nothing | the people worrying about you at home get no comfort from a book in the nav station |
What to look for in a digital boat logbook
The bar is not “an app that stores entries.” The bar is an app that works the way logging actually happens: one thumb, mid-watch, boat moving, no signal. That means offline-first (entries queue aboard and sync when the signal returns), automatic position capture so an entry takes seconds, full-text search across every passage you have ever logged, and open exports — CSV, PDF, plain text — so your years of records are never hostage to any vendor, including us.
This is the checklist WatchKeeper was built against. The WatchKeeper Log Book is offline-first, one-thumb, searchable end to end, and exports in four formats. And because the log already knows where you are, WatchKeeper turns it into twice-daily plain-language shore briefs for the people at home — the thing no paper log ever did.
The logbook and the float plan work together
The logbook records the voyage; the float plan tells someone ashore what to do if the voyage goes quiet. They share most of their raw material — boat, crew, route, timings — which is why WatchKeeper generates the float plan from the passage you already entered, and keeps your shore contact briefed from the log while you are out there.
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Boat logbook FAQ
What should a boat logbook contain?
At minimum each entry should record the date and time, position, course and speed, wind and sea state, barometer reading, engine hours if motoring, and remarks — sail changes, gear issues, crew watch changes, and anything unusual. On passage, entries are traditionally made every hour on the hour.
Is a logbook legally required on a recreational boat?
For most recreational vessels there is no legal requirement to keep a logbook, though rules vary by flag state and commercial vessels are a different matter. In practice the logbook earns its keep anyway: it is your evidence in an insurance claim or incident investigation, your maintenance memory, and your dead-reckoning fallback if the electronics fail.
Why keep a logbook when the chartplotter records the track?
The plotter records where the boat went, not what happened aboard: the reef you tucked in before the squall, the alternator belt that started squealing, the barometer trend that told you the front was early. A track is data; a logbook is judgment. And when the plotter dies, the last written position is what you navigate from.
Should I use a paper or digital boat logbook?
Paper never runs out of battery, but a single paper book is also a single point of failure: it gets wet, it stays aboard, and it cannot be searched. A good digital logbook is offline-first (works with no signal, syncs later), exports to open formats so your data is never trapped, and shares the log with people ashore. Many crews run both: quick paper scratch entries, digital as the master record.
What is the best boat logbook app?
Look for offline-first logging (a logbook that needs signal is not a logbook), one-hand entry designed for a moving boat, automatic position capture, full-text search across past passages, and export to CSV or PDF. WatchKeeper does all of this and adds twice-daily AI shore briefs for family ashore — and the Coastal tier is free.