Blackfish
A free race-start computer for sailors: line bias, burn time and the countdown, plus session recording, right on your phone.
Runs in your browser today, free: no account, no download required to try it.
What it does
Four pages, one tab bar — like a chartplotter, without the hardware. Phone-only for now.
Start-line analytics
Ping the pin and boat end for live bias and burn time (time-to-start minus time-to-line). Countdown defaults to RRS 5-4-1-0, or set your own sequence, with sound signals and one-tap sync to the nearest one.
A dashboard you build
SOG, COG, heel, the start timer, line readout, an optional wind dial — drag, resize, and arrange them like a home screen. Your layout saves automatically.
Chartplotter-style route view
Heading-up by default (north-lock is a setting), with draggable line markers to nudge a GPS ping into place, plus one-tap recenter.
Wind, without a compass
Hold steady on both tacks and Blackfish works out true wind and tack angle from GPS alone — then keeps refining it as conditions shift, with header/lift alerts.
Record every session
Start/stop recording from the Route page. Every session saves locally — viewable on the map, renameable, and exportable as a standard GPX track.
Races, solo or with a crew
Schedule a race day and share the code — every boat syncs to the same start, set by the host or, if they're not around, by another boat. Anyone with the code can watch live, no app needed.
Built for the cockpit
Screen lock against wet-screen taps, six color themes (night-vision red, high-glare daylight, more), and independent units for speed, wind speed, and distance.
Get it on your phone
Blackfish is a web app first: here's what's available now, and what's planned.
Install from your browser
Open the app, then add it to your home screen. It behaves like an installed app from there: its own icon, no browser chrome, and it keeps working offline.
- Open /app/ on your phone
- Open your browser's menu
- Choose "Add to Home Screen"
Native Android app
A real installed app - unlike the browser version, it keeps tracking your position with the screen off or the phone in a pocket. Android shows a tracking notification while it runs; that's required, not a bug.
Not on the Play Store yet, so Android will flag it as an "unknown source" - expected, not a warning sign. Allow it for your browser, then open the download to install.
An iOS version is a bigger, separate lift and isn't scheduled.
Download APK