Rainbow's End Logbook

The last night of the charter, and nobody remembers where you anchored on Tuesday.

Logbook keeps one voyage a day at a time: where you left, where you arrived, a note, the pictures, and what it cost. It works the same on a week's charter and on a weekend aboard your own boat.

It is a logbook for the voyage, not the boat. Most logbook apps ask for engine hours and tank levels. Logbook asks for her name, the dates, who was aboard, and — when she is chartered — the company and the base. Then the days.

A DAY — A passage or a lay day. A passage has where you left and where you arrived, and the nautical miles if you know them; a lay day has only where she lay. A note in your own words. Two passages on one date are two days in the book.

PICTURES — Up to six a day, from your library or the camera, each with a caption. They are copied into the app at 1,200 pixels on the long side, and they stay on this device.

POSITION — Tap Mark position at the anchorage and the phone's GPS writes the spot into the day as degrees and minutes, the way a chart reads it. Once, when you ask; never in the background.

THE LEDGER — What the voyage cost, in seven categories: provisions, meals ashore, fuel, fees and permits, transport ashore, moorings and transient dockage, other. A donut shows where the money went, and the total over the days aboard says what a day cost. A free anchorage can be noted with no amount.

THE SUMMARY — Days written of days aboard, passages and lay days, the miles, the longest passage, every place in the order you first saw it.

SHARE — When the voyage is over, Share makes a PDF logbook: a cover with the boat, the dates and the crew; a page for each day with its notes and pictures; the ledger with its donut. It goes to the share sheet, so everyone who was aboard can have the book by email or AirDrop.

A finished sample — a weekend on Galveston Bay aboard the ketch Rainbow — shows every screen before you enter anything. Copy it and change it, or start fresh.

WHAT IT WON'T DO — Keep engine hours, tanks, fuel fills, gear or maintenance: that is Rainbow's End Manifest, the book of the boat. Track you: the GPS is read once, at your tap. Put your logbook on a server: it lives on your phone and leaves only as the PDF you send.

We built it aboard our ketch Rainbow, for charter weeks and weekends on the bay.

Fully offline. No account, no subscription, no server, no tracking. Your pictures and positions stay on your device; nothing you enter leaves it unless you share the logbook yourself.

Logbook is a record of the voyage, not a navigational document, and not a substitute for the skipper's judgment. Miles are what you enter; a marked position is the phone's reading at that moment.

May you find a rainbow's end and treasure found wherever you sail or set your anchor.

Apps for sailors, by sailors.