The essentials in 30 seconds
- Coastal cruising + coastal hopping: mechanical B&G 213 (1 040 €) or entry-level ultrasonic Triton² wireless pack (1 499 €) is sufficient. Accuracy ±1° heading, 5 Hz updates — enough for safe sailing.
- Offshore cruising + passage: vertical ultrasonic B&G WS710 (2 043 €) or WS720 1.1m (2 605 €). No bearings to wear, maximum salt/UV resistance, 10+ year reliability.
- Offshore racing: high-frequency 3D ultrasonic — B&G WS730S Ocean spec 1.4m (3 080 €) or NKE 3D (NKE catalog order after Skysat reactivation). 10-20 Hz measurements, heel/heading compensation, essential for racing target optimization.
- Wireless or wired? Wireless (WS320) = 1 h installation, but battery must be replaced annually. Wired (WS310/WS710/WS720) = 4-6 h installation (mast cable run), but long-term reliability and stable N2K power.
- Workshop verdict: 60% of our 30-50 ft sailboat installs use B&G WS320 wireless (cruising) or WS710/720 wired (comfort cruising). 100% of offshore racing installs use 3D ultrasonic, brand depending on existing computer ecosystem.
The sailboat anemometer is the instrument that powers the entire decision-making chain in sailing navigation: autopilot compensation in wind mode, VMG calculation, polars, heading optimization upwind. Inaccurate or delayed measurements propagate to all downstream indicators. That’s why racing sailboats invest €3 000-5 000 in an Ocean spec sensor, while cruising boats can settle for a €1 000 mechanical sensor.
This article distinguishes the two main technical families, presents the brands distributed by Skysat, and provides a workshop verdict by program. For NMEA 2000 cabling of a wind sensor, see our article NMEA 2000 backbone, drops, terminators.
Why the anemometer matters (more than you think)
Three technical uses make the wind sensor strategic:
- Autopilot in wind mode. The autopilot follows an apparent or true wind angle (close-hauled, reaching, running). If the sensor is delayed by 2 seconds or inaccurate by ±5°, the autopilot oscillates constantly — unnecessary fatigue + VMG loss + risk in rough seas.
- Polars and performance. Racing sailboats know their polars (target speed based on true wind and angle). Without a precise and fast sensor, it’s impossible to compare real-time performance with the theoretical target. This is what separates a high-performance crew from one that "does what it can."
- Sail and trim choices. Decisions on mainsail/headsail, genoa/code zero, spinnaker/gennaker depend on true wind speed and angle. A ±2 knot measurement ruins the optimal choice — especially during wind transitions (12-15 knot zone where you choose between J1 and J2 on IRC).
Mechanical anemometer — operation, brands, limitations
The historic technology, present on pleasure sailboats since the 1970s. A cone of cups rotates with the wind (speed), and a vane orients itself into the wind (direction). Two analog sensors send signals to the onboard electronics.
B&G 213 — the mechanical cruising reference
Skysat distributes the B&G 213 masthead unit (1 040 €) + 213 standard spar (480 €) + 50 m mast cable (570 €). Designed for B&G H5000 and Triton² systems. Accuracy ±1°, speed up to 60 knots, NMEA 0183 output or dedicated 213 interface.
- Advantages: robust (used for 30 years in ocean racing), controlled price, immediate readability (vane visible from the deck).
- Limitations: bearings wear out (3-5 year lifespan in sustained sailing), accuracy drops in strong winds due to mechanical turbulence, does not measure vertical component (rotation on deck due to swell).
- For whom: 30-45 ft cruising sailboat, coastal or offshore non-racing program.
Spare parts available
- WS300/700 vane replacement (48 €)
- Speed cups (31 €)
- Wind angle bearing WS300/WS700 (83 €)
- WS300 speed bearing (92 €)
The fact that B&G still sells spare parts shows the real longevity of mechanical sensors when well maintained — 10-15 years with overhaul every 3-5 years.
Ultrasonic anemometer — operation, brands, advantages
No moving parts. The sensor emits ultrasonic pulses between 2 or 3 pairs of transducers (depending on vertical 2D or 3D). Wind shifts the propagation of the waves — calculating the time of flight gives wind speed and direction.
B&G WS320 wireless (entry level)
The Triton² wireless WS320 pack (1 499 €) is our reference for 30-40 ft sailboat retrofits that don’t want to run a cable through the mast. WS320 pack + N2K interface (449 €) if you already have Triton² displays. Battery replaceable annually (WS320 battery = 22 €).
B&G WS310/WS710 wired (comfort cruising)
The Triton² wired WS310 pack (2 028 €) and the WS710 vertical 0.8 m (2 043 €) add the reliability of wired systems (no battery) and long-term stability. The WS710 is the workshop reference for 35-50 ft offshore cruising sailboats.
B&G WS720/WS720S/WS730S (ocean racing)
The Ocean spec range — WS720 1.1m (2 605 €), WS720S Ocean 1.05m (2 865 €), WS730S Ocean 1.4m (3 080 €) — is designed for offshore racing: optimized accuracy, high-frequency sampling, native integration with B&G H5000 CPUs (Hydra 1 139 € or Performance 2 899 €).
NKE Marine Electronics — the French racing standard
The NKE system equips most French offshore racing sailboats (IMOCA, Class40, Mini, Figaro). The NKE 3D anemometer sensor measures the vertical component of the wind (useful in swell to avoid false corrections by the autopilot). Skysat’s NKE catalog is being reactivated — contact us for a racing project quote.
Calypso (compact ultrasonic)
Spanish brand specializing in compact and autonomous solar ultrasonic sensors. Very popular on charter boats and light refits. Not currently distributed by Skysat, but an interesting option for specific uses.
3D and lidar — where we stand in 2026
True 3D sensors measure the 3 components of the wind (fore/aft, port/starboard, up/down). The WS720S and WS730S do this, as do the NKE 3D. This is useful in rough seas where the boat moves on 3 axes — without the vertical component, the autopilot can misinterpret swell as a wind change and correct unnecessarily.
Lidar sensors (optical measurement via laser interferometry) remain confined to the high-end professional racing world (America’s Cup, IMOCA). They are not marketed for recreational use in 2026 — their interest in cruising remains marginal compared to their price (€10 000-30 000 per unit).
Technical comparison table of main models
2026 distributor prices in France, sensor only (separate interface if needed for the complete pack).
| Model | Technology | Measurements | Frequency | Wireless | Heading accuracy | Sensor price (excl. VAT) |
|---|---|---|---|---|---|---|
| B&G 213 | Mechanical | Speed + heading (2D) | 2 Hz | No | ±1° | 1 040 € |
| B&G WS320 | Ultrasonic 2D | Speed + heading | 1 Hz | Yes (radio) | ±2° | 449 € sensor only |
| B&G WS710 0.8 m | Ultrasonic 2D | Speed + heading | 5 Hz | No (wired) | ±1° | 2 043 € |
| B&G WS720 1.1 m | Ultrasonic 2D | Speed + heading | 10 Hz | No | ±0.5° | 2 605 € |
| B&G WS720S Ocean | Ultrasonic 3D | 3D + temp | 10 Hz | No | ±0.3° | 2 865 € |
| B&G WS730S Ocean | Ultrasonic 3D | 3D + temp + air pressure | 20 Hz | No | ±0.3° | 3 080 € |
| NKE 3D HR II | Ultrasonic 3D | 3D + temp | 10 Hz | No | ±0.3° | ~2 800 € (on request) |
Wireless or wired: selection criteria
Wireless (WS320) — when it makes sense
- Retrofit on sailboats where no cable has been run through the mast (common on older 8-10 m boats).
- Charter boats where battery lifespan is not an operator problem (annual replacement included in warranty).
- Limited installation budget: 1-2 h vs 4-6 h for wired with mast cable run.
- No need for sampling frequency > 1 Hz.
Wired (WS310, WS710, WS720, WS730, NKE) — when it’s mandatory
- Offshore racing where 5-20 Hz frequency is needed for wind-mode piloting.
- Offshore cruising where replacing a wireless battery is not feasible at sea.
- 45+ ft sailboats where cabling already exists (mast cable run in place on new builds ≥ 2010).
- Need for accuracy < 1° heading and < 0.5 knot speed.
Examples by program: coastal cruising → offshore racing
Coastal cruising + weekend (8-12 m sailboat)
Recommended solution: Triton² WS320 wireless pack (1 499 €) = wireless sensor + 2 Triton² displays + N2K interface. 1 h installation, 12-18 month battery life, accuracy more than sufficient for coastal use.
Offshore cruising comfort (35-50 ft sailboat)
Recommended solution: B&G WS710 0.8 m wired (2 043 €) + WS310 N2K interface (155 €) + 2 Triton² displays (462 € each). Total ~€3 130 materials + 6-8 h workshop installation (mast cable run). 10+ year reliability without intervention.
Offshore racing IRC / IMOCA Coastal (40-55 ft sailboat)
Recommended solution: B&G WS720S Ocean spec (2 865 €) + H5000 CPU Hydra (1 139 €) + racing displays such as 30/30HV (1 700 €) + compass computer integration Precision 9 (533 €). Total ~€6 300 + 10-15 h installation.
Pure offshore racing (IMOCA, Class40, Mini, Figaro)
Recommended solution: NKE 3D HR II + NKE Performance central (project quote) or B&G WS730S Ocean (3 080 €) + H5000 Performance (2 899 €) + Madintec integration for advanced autopilot (see our hydraulic vs electromechanical ram article). Total ~€10 000 materials + 30-50 h project.
5 common installation errors observed in the workshop
Anemometer errors — seen in the Skysat workshop
- Sensor misaligned with the boat’s axis. The sensor’s 0° must exactly match the bow. A 5° misalignment = wind heading reading permanently offset by 5° — invisible until the first close-hauled sailing session where the polars no longer match. In the workshop, alignment is validated with GPS + compass before commissioning.
- Sensor too low on the mast. Wind is turbulent in the top 20% of the mast (interaction with mainsail, headstay, mast itself). Always mount the sensor 30-50 cm above the masthead for clean wind. On sailboats where the mechanical vane is historically at the masthead, the ultrasonic sensor replaces it but must extend a few cm above.
- Mast cable run parallel to a motor or windlass cable. The anemometer cable carries a very sensitive millivolt signal. Running it next to a cable carrying 80 A at startup induces measurable electrical noise. Always separate signal cables (anemometer, antenna) from power cables (winches, propulsion, starter).
- Commissioning without offset calibration. Each sensor has a manufacturer offset (zero angle correction, speed correction). Not calibrating = accuracy reduced to ±5° instead of ±1°. Calibration takes 10 minutes via the manufacturer’s app or display, but is often forgotten.
- Vertical installation on a mast that is not vertical. If the boat heels or rigging deforms the mast, the sensor is no longer vertical relative to the waterplane. This introduces a variable offset that depends on heel. 3D models automatically correct this; 2D models do not — plan ahead if the boat’s program involves significant heel.
FAQ — Practical sailboat anemometer
How high should the sensor be installed on the mast?
Minimum 30-50 cm above the masthead to avoid turbulence from the mainsail and headstay. On sailboats with a gaff mainsail (traditional racing crew), mount up to 80 cm. Higher = cleaner wind, but more windage and breakage risk. The 50 cm mark is a good cruising/racing compromise.
Can I replace a mechanical sensor with an ultrasonic one without changing the onboard electronics?
Yes in 90% of cases, provided there is an NMEA 2000 or 0183 interface on the existing electronics. The ultrasonic sensor connects via a dedicated interface (B&G WS310 N2K at 155 €) and publishes its data on the N2K bus, read by all displays. The existing mast cable can often be reused if the section and length are suitable. Validate with an audit before ordering.
How many years does an ultrasonic anemometer last?
Without moving parts, ultrasonic lifespan is limited by electronics and housing waterproofing. Field returns for B&G WS720/WS730: 10-15 years on average, sometimes more. NKE 3D HR II: 12-18 years with a service every 5 years. The #1 mortality factor is water ingress (aging seal) — hence the importance of quality installation and choosing a marine-certified IP67 model.
Why does my anemometer read higher wind with full mainsail?
This is the Venturi effect. The mainsail creates an accelerated wind zone at the top of the mast where the sensor measures. Depending on mainsail shape, depth of draft, and point of sail, wind amplification of 10-30% in true wind is observed. This is normal and well known — polars are calculated taking this bias into account. If the reading becomes absurd (doubled), there is a sensor or calibration defect.
WS320 wireless — can I control it from my onboard computer?
Yes via the NMEA 2000 interface of the WS320 pack (449 €). The wireless sensor sends via radio to a base connected to the N2K bus. The onboard computer (or WiFi tablet) then reads the N2K data via a router. Radio latency is 100-200 ms in worst case — invisible for navigation, but noticeable in racing optimization where wired is preferred.
How to calibrate the 0° heading of the sensor after installation?
B&G workshop method: (1) boat stationary, fixed GPS, (2) Triton² display wind calibration menu, (3) note the wind heading value displayed, (4) correct the sensor offset so it matches the true wind measured by a reference anemometer or by drift of a telltale. For NKE: Toplink app or Multigraphic display, wind calibration menu → zero offset. Always do this in calm waters with stable 5-15 knot wind.
Is a 3D sensor mandatory for offshore cruising?
Not mandatory but highly recommended for boats over 40 ft in rough seas. The vertical component of the wind (pumping in swell, accelerations over waves) creates errors in 2D sensors that the autopilot interprets as heading changes — resulting in constant oscillations in rough seas. 3D filters this out. On a 30 ft cruising sailboat in summer, 2D ultrasonic is more than sufficient.
Skysat distributes B&G, NKE Marine Electronics, Raymarine, Garmin, and Navico. This article reflects our experience installing wind sensors on over 60 sailboats 2020-2026, cruising and racing. 2026 distributor prices are indicative for France; technical specifications are sourced from manufacturer datasheets and field measurements during sailing.
