8
CALIBRATION
The software in the compass allows the compass to 'learn' the magnetic fields in the vessel that are
causing the deviation errors. By following the simple procedure below, deviation errors are reduced to
an insignificant level.
AUTOMATIC CALIBRATION
Align the markings on the top of the compass approximately with the fore-and-aft line of the vessel by
rotating the compass unit within its mounting bracket.
The compass calculates the correction coefficients each time the boat completes a 540° (one and a
half circles) turn, provided:
(a) The 540° turn is completed without changing the direction of the turn.
(b) The rate of change of heading does not exceed 3
°
/second during the 540° turn i.e. 540°
must not be achieved in less than three minutes. (See 1 below).
(c) The rate of change of heading does not fall below 0.2
°
/second during the 540° turn i.e.
540° must not be achieved in more than forty five (45) minutes. (See 1 below).
(d) Automatic calibration has not been inhibited as described in paragraph 5.1.1 of this book.
(e) The change in heading is constant.
These criteria are chosen to ensure that normal sailing manoeuvres do not inadvertently initiate the
calibration sequence.
