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 to sail well.
- Offshore cruising + passage racing: 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 (order via Skysat catalog reactivation). 10-20 Hz measurements, heel/heading compensation, essential for racing target optimization.
- Wireless or wired? Wireless (WS320) = 1-hour installation, but battery must be replaced annually. Wired (WS310/WS710/WS720) = 4-6-hour installation (mast cable run), but long-term reliability and stable N2K power.
- Workshop verdict: 60% of our 30-50ft 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 processor ecosystem.
The sailboat anemometer is the instrument that powers the entire decision-making chain in sailboat navigation: autopilot compensation in wind mode, VMG calculation, polars, heading optimization upwind. An imprecise or delayed measurement propagates to all downstream indicators. That's why racing sailboats invest €3,000-5,000 in an Ocean spec sensor, while a cruising boat 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 wiring 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 2 seconds late or inaccurate by ±5°, the autopilot constantly oscillates — unnecessary fatigue + VMG loss + risk in rough seas.
- Polars and performance. Racing boats 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 to the theoretical target. This is what separates a high-performance crew from a crew that "does what it can."
- Sail and trim choices. Decisions on mainsail/genoa, code zero/spinnaker depend on true wind speed and angle. A ±2-knot measurement kills the optimal choice — especially in wind transitions (12-15 knot zone where you choose between J1 and J2 on IRC).
Mechanical anemometer — operation, brands, limits
The historic technology, present on pleasure sailboats since the 1970s. A cone of cups rotates with the wind (speed), a vane orients into the wind (direction). Two analog sensors send signals to the onboard electronics.
B&G 213 — the cruising mechanical reference
Skysat distributes the B&G 213 masthead unit (€1,040) + 213 standard spar (€480) + 50m 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).
- Limits: bearings to wear (3-5 year lifespan in sustained sailing), accuracy drops in strong winds due to mechanical turbulence, does not measure the vertical component (rotation on deck in swell).
- For whom: 30-45ft 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)
- Speed bearing WS300 (€92)
The fact that B&G still sells spare parts shows the real longevity of well-maintained mechanical sensors — 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 2D vertical or 3D). The 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 30-40ft sailboat retrofits that don't want to run a cable through the mast. WS320 + N2K interface pack (€449) alone 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 0.8m vertical (€2,043) add the reliability of wired (no battery) and long-term stability. The WS710 is the workshop reference for 35-50ft 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 H5000 CPUs (Hydra €1,139 or Performance €2,899).
NKE Marine Electronics — the French racing standard
The NKE system equips the majority of 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 NKE catalog is being reactivated — contact us for offshore racing project quotes.
Calypso (compact ultrasonic)
Spanish brand specializing in compact and solar-powered ultrasonic sensors. Very popular on charter boats and lightweight 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 all 3 wind components (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 by laser interferometry) remain confined to the high-end professional racing world (America's Cup, IMOCA). They are not sold for recreational use in 2026 — their benefit in cruising remains marginal vs. their price (€10,000-30,000 per unit).
Technical comparison chart of main models
2026 distributor prices in France, sensor only (separate interface if needed for complete pack).
| Model | Technology | Measurements | Frequency | Wireless | Angle accuracy | Sensor price HT |
|---|---|---|---|---|---|---|
| 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 0.8m | Ultrasonic 2D | Speed + heading | 5 Hz | No (wired) | ±1° | €2,043 |
| B&G WS720 1.1m | 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: choice criteria
Wireless (WS320) — when it makes sense
- Retrofit on sailboats where no cable has been run through the mast (common on older 8-10m boats).
- Charter boats where battery lifespan is not an operational issue (annual replacement included in warranty).
- Limited installation budget: 1-2 hours vs 4-6 hours 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 to steer by wind.
- Offshore cruising where wireless battery replacement is not feasible at sea.
- 45+ ft sailboats where cabling already exists (mast cable run standard on new boats ≥2010).
- Need for accuracy < 1° angle and < 0.5 knot speed.
Examples by program: coastal cruising → offshore racing
Coastal cruising + weekend (8-12m sailboat)
Recommended solution: Triton² WS320 wireless pack (€1,499) = wireless sensor + 2 Triton² displays + N2K interface. 1-hour installation, 12-18-month battery life, accuracy more than sufficient for coastal use.
Comfort offshore cruising (35-50ft sailboat)
Recommended solution: B&G WS710 0.8m wired (€2,043) + WS310 N2K interface (€155) + 2 Triton² displays (€462 each). Total ~€3,130 parts + 6-8-hour workshop installation (mast cable run). 10+ year reliability without intervention.
IRC / IMOCA Coastal offshore racing (40-55ft sailboat)
Recommended solution: B&G WS720S Ocean spec (€2,865) + H5000 CPU Hydra (€1,139) + racing displays like 30/30HV (€1,700) + Precision 9 compass (€533) integration. Total ~€6,300 + 10-15-hour installation.
Pure offshore racing (IMOCA, Class40, Mini, Figaro)
Recommended solution: NKE 3D HR II + NKE Performance CPU (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 parts + 30-50-hour 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 of the boat. A 5° alignment error = wind heading reading permanently offset by 5°, with no visible error until the first upwind sailing when the polars no longer match. In the workshop, alignment is validated by GPS + compass before commissioning.
- Sensor too low on the mast. Wind is turbulent in the top 20% of the mast (interaction with mainsail, spreader, mast itself). Always mount the sensor 30-50cm above the masthead to get 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 engine or windlass cable. The anemometer cable carries a very sensitive millivolt signal. Running it next to a cable that carries 80A 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 = reduced accuracy to ±5° instead of ±1°. Calibration takes 10 minutes via the manufacturer's app or display, but is often forgotten.
- Vertical mounting 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 mounted on the mast?
Minimum 30-50cm above the masthead to avoid turbulence from the mainsail and spreaders. On sailboats with a boom-footed mainsail (traditional racing crew), mount up to 80cm. Higher = cleaner wind, but more windage and breakage risk. The 50cm 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 cross-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 the 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 5-year overhaul. The #1 cause of failure is water ingress (aging seal) — hence the importance of quality installation and choosing a marine-grade IP67-certified 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 the mainsail cut, depth of draft, and point of sail, wind amplifications of 10-30% in true wind are observed. This is normal and well-known — polars are calculated taking this bias into account. If the reading becomes absurd (doubling), 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 100-200ms in worst case — invisible for navigation, but noticeable in racing optimization where wired is preferred.
How do I calibrate the 0° heading after installation?
B&G workshop method: (1) boat stationary, GPS fixed, (2) Triton² display wind calibration menu, (3) note the displayed wind heading value, (4) correct the sensor offset so it matches the true wind measured by a reference anemometer or by the drift of a telltale. For NKE: Toplink app or Multigraphic display, wind calibration menu → zero offset. Always perform 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 40ft in rough seas. The vertical component of the wind (pumping in swell, accelerations over waves) creates errors on a 2D sensor that the autopilot interprets as heading changes — result: constant oscillations in rough seas. 3D filters these. On a 30ft cruising sailboat in summer, 2D ultrasonic is more than sufficient.
Skysat distributes B&G, NKE Marine Electronics, Raymarine, Garmin, and Navico brands. This article reflects our experience installing wind sensors on over 60 sailboats 2020-2026, cruising and racing. 2026 HT prices are indicative of the French distributor; technical specifications are from manufacturer datasheets and field measurements during sailing.
