Start line precision and much more
The whole race day, run automatically — from the first warning signal to the posted scoreboard.
The system
How the system works
Built around a custom GPS nautical stack, the whole race day runs automatically, from the first warning signal to the posted scoreboard. Shore, boats and results, all on one system.
Clubhouse (base station)
- Runs from the clubhouse ashore, or from the committee boat — no shore site needed.
- Either way it is a fixed GNSS receiver on a surveyed position.
- It knows its own coordinate, so it can measure live satellite error: ionospheric drift, clock and orbit.
- Broadcasts that correction to every boat on the course.
Corrections
- One correction, sent continuously to every device.
- Comes from whichever base station is in use that day — the clubhouse, or the alternate on the committee boat.
- The whole fleet measured against a single reference.
- Errors cancel instead of compounding.
- Two boats side by side read the same distance to the line.
Start boat (alternate base station)
- Starboard end of the line, fixed by a corrected GNSS position.
- Can carry an alternate base station — mount it here and no shore site is needed.
- Ashore or afloat, the correction the fleet receives is identical.
- Recorded once. No transit to sight, no eyeballing the pin.
- Every boat races against the same coordinate.
Pin
- Port end, pinged the same way.
- Two surveyed endpoints define the line as a geodesic.
- The line the app draws is the line the committee set — bias included.
The line
- One line, defined once, shared by the whole fleet.
- Distance measured perpendicular from your bow, not your phone.
- Offset for where the mount sits on the boat.
- Sub-metre resolution: on the line or over it is measurable, not arguable.
- OCS is detected, not disputed — boats over early are flagged automatically.
Windward mark
- Set from the support vessel, published the moment it is dropped.
- Move the mark and the course updates on the water.
- No VHF call. No confusion about which mark is live.
The fleet
- One synchronised start sequence across the fleet.
- Timing disciplined against GNSS time, not the handset clock.
- Every device counts down to the same instant, whatever the network.
Support vessel
- Lays and moves marks; coordinates captured on the spot and published.
- Its own position is live on the same map.
- Every boat on the water is tracked.
- A capsize, a stopped boat or an alert shows up with a position to steer to.
- The crew sees it without waiting for a call from shore.
Coach boat
- Watches the race live with every boat's track on screen.
- Approach angles, timing on the line, tack-by-tack gains up the beat.
- Debrief on the water, while it still means something.
- Pre-race start practice: set a line, run sequences, review who was early or late.
On the boat
- Runs on the phone you already own, in a class-approved mount.
- Fixed, known position on the boat with an unobstructed view of the sky.
- Clean satellite fix and a consistent reference for every measurement.
Racing
- Live distance to line, time to burn, laylines and course position.
- Every fix logged as you sail.
- Replays afterwards at the accuracy it was recorded.
- Start approach, first cross, every gain and loss up the beat.
Hover a feature to see what it does.
Tap a feature to see what it does.
Community fun
Groups, challenges and a feed that fills itself from racing and training.
Fairer racing
One start line, set once, shared by the whole fleet, not thirty different guesses.
Better performance
Race with live numbers, then replay every start and see what actually happened.
How to get onboard
Four steps from the app store to your first start
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1
Download the RaceZen app - coming to the Apple Store and Google Play soon
It runs on the phone you already own. No dedicated instruments, no wiring.
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2
Mount the phone where you can read it
Deck, mast or bulkhead. Clear view of the screen, clear view of the sky.
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3
Set the start sequence and sail
The countdown runs itself and the numbers update themselves. Once you have launched there is nothing to press.
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4
Replay the race and see what happened
Your track and the fleet's, with the wind trace alongside.
Six people. Six benefits
Everyone on the water has a different race day. Pick yours — each route lands on the part of RaceZen you actually touch.
Start better. Get OCS'd less
Then replay every start and improve. Live speed, heading, heel and VMG while you race — full analysis when you are back ashore.
The race office in your pocket
Confident OCS calls, a live fleet map, automatic results and RC safety built in. Up to 100 boats across 6 concurrent fleets.
See the whole squad at once
Watch every boat live from the RIB, then debrief with the real tracks instead of what you happened to catch.
Start well. Stay safe
Follow them with a code they control, and know the club can see the whole fleet on the water.
Your fleet, between races
Groups, challenges, regattas and sail plans — the people you race against, in one place, all week.
Race days worth sharing
A live view for spectators and a replay for your channels, straight out of the racing you already run.
Big numbers. No fiddling
Mounted where you can read it at a glance, in a layout you can take in without leaving the tiller.
The live display, as it appears on the water
Over ground, updated live. The number you trim against.
Digital compass heading, the one readout that stays available in class-legal mode.
Velocity made good toward the mark, so you can tell fast from pointing.
Read from the phone's own sensors. Flat is fast, and now you can see how flat.
Set the phone up before you launch and then leave it alone. The numbers update themselves and the screen stays awake, so both hands stay on the boat.
Class-legal mode · available early 2027
GPS runs the start. The sailor sees a compass and a clock
When a class-legal start sequence begins, the race committee forces every boat into a restricted display. The system still uses full GPS to make the official call — the competitor simply is not shown it.
Countdown, compass, recall
- Countdown and elapsed time
- Compass heading
- Individual Recall, and whether it applies to you
- Your clearance once you are back
- Finished
No speed. No heel. No distance to line. No time to line. No laylines. No wind. No tactical suggestions. No history.
The whole picture
- Full fleet positions against the surveyed line
- Every OCS determination, live
- Distance-to-line geometry for the whole fleet
- Finish detection and finish times
- Safety map — last known positions, non-responding boats
Data flows to the race committee, not to the competitor. One-way, by design.
Where class rules stand today. Class-legal mode is built and it works. It is not a claim that RaceZen is permitted under every class rule as they are written today — some classes, including ILCA and RS Aero, currently restrict competitor GPS and electronics, and that is a rule change for the class to make. For club and open racing, RaceZen is available now. For restricted classes, class-legal mode is ready the moment the rule moves.
RaceZen RMS · for the race committee · coming early 2027
One system, end-to-end race management
The regatta, the course, the start, the recalls, the finishes and the results — run from the committee boat, in the order a race day actually happens.
The race screen in RaceZen RMS
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1
The flag signals, in front of the race officer
AP, the class flag, P, X and First Substitute are on the committee screen as the sequence runs, so the signals and the timing come from one place. On the water the fleet sees the countdown.
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2
A starting queue, not a scramble
The next fleet is loaded and counting while the last one races. Class, flag and warning time are set once and the sequence runs itself.
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3
Every competitor, filtered by state
Active, OCS, started, finished, not started, not present. The list that used to be a wet sheet of paper is now the thing making the calls.
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4
Safety on the same screen
Fleet safety is not a separate app. Last known positions and alerts sit alongside the race controls.
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5
Race committee status · early 2027
On the sailor's screen, Waiting for RC becomes the countdown, then OCS or CLEAR, then RACING — pushed from the committee boat with nothing to press. It arrives with RaceZen RMS.
Which phone should you race with?
What matters is whether your phone can hear two satellite bands instead of one. These are the models we know can.
Dual-band phones
- Google Pixel 6, 7, 8 and 9 — the standard models, not the a versions
- Samsung Galaxy S20 FE 5G, the Snapdragon version
- iPhone 14 Pro, 15 Pro and 16 Pro, including the Max models
- iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max and iPhone Air
These phones hear two satellite bands at once, which is what RaceZen is built around.
Single-band phones
- Google Pixel 6a, 7a, 8a and 9a
- iPhone 14, 15 and 16 — the non-Pro models
- iPhone 16e and iPhone 17e
- Most budget Android phones
They still record tracks, join races and work with RaceZen. They hear one satellite band instead of two, so we do not put them in the recommended list for racing.
Power on the water
The phone lasts longer than the race day
The question everyone asks first. Here is the tested figure, and what moves it.
Drawdown testing with the RaceZen app running gave about fifteen hours. That is a figure from a test, not a marketing number.
Rigging, launching, a postponement on the water, three races and the sail home. A race day does not come close to using it up.
The countdown, the numbers, the recall status and the tracking are all in the same app. There is no second timer or tracker running alongside it.
A hot phone in full sun will slow itself down. Angle the mount towards you rather than at the sky and let air move around it — which is what the vents are for.
What the figure means. Fifteen hours is what drawdown testing gave with the app running. It is a measured result rather than a guarantee, and the real number moves with the handset and its age, screen brightness and air temperature. An older phone whose battery has lost capacity will not reach the same figure.
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