Planned to install this in our sailboat but ran out of time before we left for Mexico last fall.  Used a similar unit on a prior Pacific crossing and it was incredible.  Currently configured for close-hauled wind display; can be extensively re-configured to provide a wide range of data (need a computer interface such as the Airmar USB interface box to reconfigure).  Comes with a 20' NMEA2000 cable; see my other auction for a 60' cable if you plan on installing masthead.

Description from Airmar:

The WeatherStation 200WX is the best choice for mobile, weather-monitoring applications. Sensor rich, in a durable, rugged, small housing that is IPX6 rated, means the 200WX can be used on moving platforms such as TV-news and military vehicles.

Knowing the dynamic true wind speed and direction is important and often mission-critical. The 200WX calculates the dynamic true wind speed and direction based upon the apparent wind (the wind you would feel on your hand if you held it out while moving), speed of the vehicle, and vehicle heading. Its internal 10 Hz GPS and three-axis electronic compass provide heading, position, speed-over-ground, and course-over-ground functionality that is necessary for dynamic true wind-data processing on a moving vehicle.

The 3D compass with dynamic stabilization provided by the three-axis rate gyro enhances the rate-of-turn data. The patented 200WX maintains dynamic compass performance in hilly and mountainous terrain—common in military situations.

Features:

• Ultrasonic measurement of apparent and Dynamic true wind speed and direction
• Barometric pressure
• Air and wind chill temperature
• Relative humidity (field serviceable option)
• Calculated dew point and heat index
• GPS position, speed over ground, and course over ground
• Three-axis, solid-state compass with dynamic stabilization
• Three-axis rate gyro supplies rate-of–turn data
• Three-axis accelerometer for best-in-class pitch and roll information
• Housing IPX6 rated for water-ingress protection
• Data output via a single cable (various lengths available)
  • NMEA 0183/ASCII serial data protocol over RS-232 interface
  • NMEA 2000 protocol over CAN