I have a small outboard in the Netherlands and spend my summer days wandering the canals. For a couple of years I used one of the free speedometer apps from the store, and it did its job. But after a four hour day on the water last month I realized I had nothing to show for it. No route, no distance, no trip history. My boat is not chartplotter worthy, so I decided the watch should do that work.
Deadreckon is the result: a free device app that turns the watch into a marine speedometer with optional trip recording.
What it does:
- Boat speed on a 180 degree gauge, with heading, time of day, distance, and trip time
- Peak and average speed at a glance
- Tap Start to record, Stop to save. The trip syncs to Garmin Connect as a Boating activity with your route, distance, speed, and time
- Or skip recording entirely and just use it as a speedometer
- Laps if you want them, off by default
- Knots, km/h, and mph, with an adjustable gauge range to match your boat
- Day, Dark, and Night color modes, added in the latest release
It runs on 40 plus watches from the Forerunner and fēnix lines through epix, Enduro, MARQ, Instinct 3, Venu, and vivoactive. The layout derives from screen geometry, so it adapts per device, but I have only hand verified a handful of faces in the simulator and my own epix Gen 2 on the water.
If something renders oddly on your watch, reply here with the model name. That is genuinely useful to me and I will fix it.
Download: apps.garmin.com/.../c571d0e8-1b44-4dc6-8cd2-68db07d1c7a4
I built this for my own boating, but I am actively developing it and would honestly like to hear what features other people on the water want. Feedback, bug reports, and ideas all welcome in this thread.