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° of heading, 5 Hz updates — enough for safe sailing.
- Offshore cruising + ocean crossing: 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 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 are B&G WS320 wireless (cruising) or WS710/720 wired (comfort cruising). 100% of offshore racing installs are 3D ultrasonic, brand depending on existing processor ecosystem.
The sailboat anemometer is the instrument that feeds the entire decision chain in sail navigation: autopilot compensation in wind mode, VMG calculation, polars, upwind target optimization. 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, whereas a cruising boat can get by with 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, beam reach, broad reach). 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. The racing sailboat knows its 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 one that "does its best."
- Sail and trim choices. Decisions on mainsail/genoa, J1/J2, spi/gennaker 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 an IRC rating).
Mechanical anemometer — operation, brands, limits
The historic technology, present on pleasure sailboats since the 1970s. A cone of cups spins with the wind (speed), a vane orients 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) + 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 vertical component (rotation on deck due to 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)
- WS300 speed bearing (€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). 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 in the mast. WS320 pack + N2K interface (€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 vertical 0.8m (€2,043) add the reliability of wired systems (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’s 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 light refits. Not currently distributed by Skysat, but an interesting option for specific uses.
3D and lidar — where do 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 shift and correct unnecessarily.
Lidar sensors (optical measurement by laser interferometry) remain confined to the world of high-level professional racing (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
Prices are 2026 distributor prices in France, sensor only (separate interface if required for complete pack).
| Model | Technology | Measurements | Frequency | Wireless | Heading accuracy | 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: selection criteria
Wireless (WS320) — when it makes sense
- Retrofit on sailboats where no cable has been run in the mast (common on older 8-10m boats).
- Charter boats where battery life is not an operator 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 required for wind steering.
- Offshore cruising where wireless battery replacement is not feasible at sea.
- 45+ ft sailboats where cabling already exists (mast cable run in place on new boats ≥2010).
- Need for accuracy < 1° heading and < 0.5 knots 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 hours workshop installation (mast cable run). 10+ year reliability without intervention.
Offshore racing IRC / IMOCA Coastal (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 hours 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 hours project.
5 common installation errors observed in the workshop
Anemometer errors — seen at 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 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 30-50cm 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 a motor or windlass cable. The sensor cable carries a very sensitive millivolt signal. Running it next to a cable carrying 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 = accuracy reduced 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 — anticipate if the boat’s program involves significant heel.
FAQ — Sailboat anemometer in practice
How high should I install the sensor on the mast?
Minimum 30-50cm above the masthead to avoid turbulence from the mainsail and headstay. On sailboats with a gaff mainsail (traditional racing crew), mount up to 80cm. Higher = cleaner wind, but more windage and breakage risk. 50cm 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 cause of failure 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, and point of sail, wind amplification of 10-30% in true-wind mode is normal. This is accounted for in polars. 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 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° of the sensor after installation?
B&G workshop method: (1) boat stationary, GPS fixed, (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 the 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 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 — resulting in constant oscillations in rough seas. 3D filters this out. On a 30ft cruising sailboat in summer, a 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 HT prices are indicative of approved French distributor prices; technical specifications are sourced from manufacturer datasheets and field measurements at sea.
