Floating IP68 case
Designed to be submerged and to float if it ever comes off the mast. target spec
SailNav Clip · for dinghies
Clip it on. Sail smarter.
A wireless wind head that powers itself from the wind, and a floating display that clicks onto your mast. Rig it in seconds, take it home to charge, and learn to trim with real numbers from your very first race.
- ≈66 gwind head (target)
- IP68floating display (target)
- 0cables on the mast
Concept illustration with a real firmware screen. Industrial design of the floating case is in progress.
The system
Two parts. Zero wires.
The wind head sits on top of the mast and broadcasts wind speed and angle four times a second. The display on the mast combines it with GPS, heading and heel, and shows you what matters for the next tack.
- 1 Wind head: wind-powered, wireless, floats, quick-release
- 2 Bluetooth LE link at 4 Hz, no pairing cable, no mast wiring
- 3 Clip display: floating IP68 case on a quick-release mast mount
- 4 Built-in sensors: GPS, 9-axis motion, compass and barometer
The wind head
Powered by the wind it measures.
No batteries to change, no cable down the mast, nothing to charge. A tiny generator in the propeller hub harvests energy while you sail and stores it in a sealed, hermetic cell.
- Charges from about 4–5 knots of wind target. Reads wind speed from about 0.5 kn.
- Weeks of reserve in a calm. The design model gives over a year asleep, and about five weeks with the display listening around the clock.
- It floats, and it is fully potted: no connectors, no openings, nothing for salt water to get into.
- About 66 g including stalk and socket (estimate; target under 80 g), so it will not upset a small rig.
- 1 Three-blade propeller, Ø 70 mm
- 2 Magnets in the hub: coreless axial-flux generator
- 3 Air-core coils sealed behind a thin wall
- 4 Fully potted electronics and Bluetooth LE radio
- 5 Hermetic rechargeable cell
- 6 Contactless magnetic angle sensor over a magnet fixed on the stalk
- 7 Vane: the whole head swivels into the wind
- 8 Stalk in a tool-free quick-release masthead socket
The display
Drop it. Dunk it. It floats.
Dinghies capsize. The Clip display is built for it: a sealed, buoyant IP68 case, four big sealed keys you can press with gloves, and a reflective screen that reads best in bright sun.
Sunlight readable
4.4" reflective memory-in-pixel screen, 320 × 240. High contrast in direct sun, very low power.
USB-C charging
Take it off the mast after sailing and charge it at home like a phone. Rechargeable lithium-polymer battery.
Sensors inside
u-blox GNSS, 9-axis motion sensor with fusion, magnetometer and barometer: speed, heading, heel and weather.
Quick-release mechanics
On in seconds. Off in seconds.
Dinghies are rigged and de-rigged every time you sail. Both parts of SailNav Clip are designed for that routine, with no tools.
-
Fit the mount once
A slim clamp stays on the mast at eye level. It sets the display angle so you never have to adjust it again.
-
Click the display in
Slide the floating display onto the mount until it clicks. Pull the release to lift it off for charging.
-
Push the head on
The wind head's stalk drops into a spring-detent socket on the masthead. Keyed flats keep the zero angle, so no recalibration.
Where you already look
On the mast, at eye level, the numbers are in your line of sight while you watch the sails and the water. No looking down into the boat in the middle of a tack.
Mount and socket geometry are concept designs; details will change during prototyping. Lift the head off before lowering the mast.
Photo: Nick Lightbody, CC BY-SA 4.0, via Wikimedia Commons (cropped)
What a dinghy sailor learns
Every tack tells a story. Now you can read it.
Keep it flat
See how many degrees of heel cost you speed. Hike harder, ease earlier, and watch the number drop.
Tack through less
Measure your real tacking angle, then work on your technique until it tightens up.
Read the shifts
A wind-shift tracker shows lifts and headers so you tack on the right one.
Dinghy boat speed comes from GPS (speed over ground); there is no through-hull log on a dinghy. True wind is computed from apparent wind and GPS speed and heading.
Technical data
SailNav Clip at a glance
Pre-production data. Values marked target are design goals or engineering estimates from our design study, to be confirmed by testing.
| Wind head (wireless) | |
|---|---|
| Type | Wind-powered swivel head: propeller for speed, vane for direction |
| Rotor | 3-blade propeller, Ø 70 mm |
| Generator | Coreless axial-flux, wound air-core coils (no cogging) |
| Wind speed | Read from about 0.5 kn; rotor starts at about 1 kn target |
| Energy harvesting | Charges from about 4–5 kn of wind target |
| Wind direction | Contactless magnetic (3D Hall) sensing; ±2° sensor, ±3° installed target |
| Energy storage | Hermetic Tadiran rechargeable cell, sealed in the potting |
| Calm reserve | > 1 year asleep; about 5 weeks with the display on 24 h/day model |
| Radio | Bluetooth LE broadcast, 4 Hz |
| Construction | Fully potted electronics, no connectors or openings; floats; UV-stabilised light-coloured housing |
| Mass | ≈ 66 g incl. stalk and socket est., target < 80 g |
| Mounting | Ø 8 mm GRP stalk in a tool-free quick-release masthead socket, keyed zero |
| Clip display | |
| Screen | 4.4" reflective memory-in-pixel, 320 × 240 (Sharp LS044Q7DH01), sunlight readable |
| Night use | No backlight in the current design; night-lighting options under evaluation |
| Controls | 4 sealed keys |
| Processor and radio | Nordic nRF54LM20A (Fanstel BM20C module), Bluetooth LE 6 |
| Positioning | u-blox MAX-M10S GNSS, built-in antenna |
| Motion and weather | 9-axis IMU with sensor fusion (BNO085), magnetometer, barometer |
| Alarm | Built-in buzzer (anchor watch, start sequence) |
| Power | Rechargeable LiPo battery, USB-C charging; battery life to be confirmed |
| Case | Floating, IP68 target |
| Mounting | Quick-release clip-on mast mount |
Pairing: put the display in pairing mode and spin the wind head next to it. Wind data is also broadcast with the standard Bluetooth Environmental Sensing profile, so phones can read it too planned.
Kickstarter · coming soon
Be first on the water with SailNav.
We are preparing our Kickstarter campaign. Leave your e-mail and we will tell you the day it goes live, with all the details of the early-backer rewards.