50 50_Afficheur_Multigraphic_um_UK_27
This page displays the current calibration value (old correction), the new calibration
value (new correction), the factors calculated from the runs (ratio FW/BW) and the
correction factor for boat speed.
2.8.2 Compass auto-adjustment
Some magnetic deviation errors are unique to each boat, due to the magnetic
environment. An auto-adjustment of the compass is required to make the compass
learn this environment and achieve acceptable accuracy.
2.8.2.1 Auto-adjustment principle
To achieve this a swing procedure is required which consists of turning the boat
through a complete and perfect 360° turn clockwise at a constant rate of turn and
boat speed.
During this procedure the compass builds its own deviation curve table. Corrections
will be applied accurately from 0 to 359° in the sectors of sluggishness and
unsteadiness.
2.8.2.2 Compass auto-adjustment procedure
Conditions to achieve a successful auto-adjustment manoeuvre:
- Steady waters without current.
- Safe distance from any source of magnetic field such as cargo ships.
- Safe area for free manoeuvre in a 5 boat length radius.
- Motor at constant low speed (2 or 3 knots).
- For the 9X compass it is not necessary to navigate see its instructions.
Warning: the auto-adjustment operation needs to be carried with a lot of care.
Motor the boat at 2 or 3 knots in a perfect circle. For the Regatta compass, the compass
swing must be performed in less than 5 minutes. Providing you match these conditions the
auto-adjustment will be successful.
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