Tidebook

The problem under the problem

Sailors were planning trips across four apps and a paper almanac. The data was all there; the trouble was reading it at a glance, one-handed, on a deck that never stops moving.

What we built

One timeline for the day: tide height as a filled curve, wind as a row of arrows, daylight as the background. A single thumb scrub moves through the hours. Everything else hides until you ask for it.

We tested every build on a real boat in the Firth of Forth. The rule was simple: if it fails with wet hands, it fails.