Filter
Top Products
RayTech Navigator User’s Guide
5-66
Compass Calibration
Compass calibration involves two procedures: Deviation and Heading
Error calibration. Calibrating Deviation corrects compass error around
the different points of the compass. Keep in mind that some instru-
mentation systems have the ability to swing (calibrate) the compass
automatically.
Heading Error calibration ensures that the heading the compass
indicates always reflects your true heading. Calibration of this kind is
usually achieved by piloting the boat along a known line of transit.
For best results, you should have your compass professionally swung.
Apparent Wind Angle Calibration
You must perform Apparent Wind Angle calibration after the mast
head wand is initially installed on your boat. Since the wand may not
lie exactly on the fore and aft line of the boat, Awa calibration is
necessary to compensate for this. The Awa should read zero when the
vane is on the centerline of the boat. If you don’t get a zero reading,
you must enter an offset value into the instrumentation system.
The amount of Awa alignment error can be established in two ways:
• Take the boat head-to-wind and read the Awa angle. If the
Awa value is not zero, you have a calibration error. This
method is less accurate than the following one.
• Perform two or three tacks upwind in even wind strength,
then compare the average Awa tack-to-tack by using
Navigator’s DataTrak utility.
The calibration must be performed under even wind strength, as
differing wind strengths will result in different Awa readings tack-to-
tack. It is also important to calibrate Awa offset in the absence of
wind shear and wind gradient; however, calibration in light air (such
as a sea breeze filling in) is not recommended.