Onwa Marine Electronics KAP-833 - Manual (Page 36)

Trim
The Trim control on the internal preset VR31 (TRIM).
When the KAP-833 first is switched on and in Standby mode, the Trim knob
should initially be set in mid position which corresponds to setting of 5.
There are circumstances in which the autopilot may set the rudder in the centre
(according to its feedback unit), but the vessel does not steer straight ahead.
Reasons for this are:
1. The rudder feedback unit may not be perfectly aligned.
2. There may be a side-wind, current, net drag, etc., which causes the vessel
to steer to one side.
The KAP-833 computer program can compensate for these errors, but may take
a few minutes to correct completely. Adjusting the trim control can eliminate
these errors immediately.
To find the correct trim setting:
With the vessel travelling ahead, switch autopilot the to power steer mode.
Adjust the trim control until the ship steers straight.
The trim control is not intended to be used for adjusting the vessel course in auto
or power steer mode.
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