True Wind Calculator

Calculate true wind direction speed from vessel speed, apparent wind direction and speed.

truewind(options)

The first argument is an options object. {speed: 6.5, heading: 200, awd: 350, aws: 5, awa: 150}

• speed - Vessel Speed
• heading - Vessel True Heading
• awd - Apparent Wind Direction (0-360) (relative to true north)
• awa - Apparent Wind Angle (0-360) (relative to bow) Overrides awd and heading options.
• aws - Apparent Wind Speed (relative to the boat). Units must match speed option.

Returns {}

Each value is rounded to nearest hundredth.

• twa - True Wind Angle
• twd - True Wind Direction (Requires heading and awd input.)
• twsr - True Wind Speed as a ratio to speed input.
• tws - True Wind Speed in units as sent to function.

var truewind = require('truewind');

var ops = {
  speed: 6.5, heading: 200, awd: 350, aws: 5
};

var res = truewind(ops); // { twa: 167, twd: 367, twsr: 1.71, tws: 11.11 }