Manual

NMEA Instrument System
7.17
The heel maximum should be set to a value which is the maximum you
would expect to see when sailing.
The leeway calculation is a function of angle of heel and the square of
the boat speed: you will have to experiment with it to get the right
values for the calibration, but expect a figure between 5 and 7.
The final value is for damping of the true wind direction. You should be
able to use a value of one in light weather—no damping—but you may
need more in heavy weather.
Note
. It is important that the instrument system boat speed is calibrated
correctly because Deckman corrections have no effect when the yacht is
upright, as when sailing downwind.
Note
. Do not expect the calibrations here to give you a perfect true wind
direction that is consistent through tacks: you will still probably need to
use the special true wind calibration tables which are described in the
next chapter.