Tidewatch

The club’s safety officer wrote to me in February. Before every trip, trip leaders were checking a tide table, a wind forecast and a swell model, each on a different website, each with its own units and time zone. It took about twenty minutes and a good memory.

The previous season there had been two near-misses. Neither was dramatic, but both came down to the same mistake: reading the tide for the wrong harbour. The club wanted an app. What they really needed was fewer chances to get it wrong.

I spent two Saturday mornings at the launch site with a notebook and a flask of coffee, and talked to eleven paddlers while they rigged their boats. I asked each of them to plan the next day’s trip out loud, on their own phone, while I watched.

Three things came up again and again:

The home screen asks for two things: where you’re launching and when. It then gives a single answer, Go, Check or Wait, with the reasons listed underneath in the order paddlers said they think about them: current, wind, swell, light.

The answer is never a black box. Every reason expands into the actual numbers, with the source and the time it was last updated. The thresholds belong to the club, not to me; the safety officer sets them in a short settings page, and different limits apply for beginners’ trips.

Designing out the wrong harbour

Launch sites are chosen from a map of the club’s twelve regular spots, and every reading on screen is labelled with the station it comes from. If the nearest tide station is more than five kilometres away, the app says so in plain words.

One line of time

Below the answer sits a single timeline for the trip window, with tide, current and wind drawn on the same horizontal axis. Testing showed this was the part experienced leaders used most; it let them see the turn of the tide against their planned return time at a glance.