Chapter 6: Adjusting Tiller Pilot Settings
63
Calibration Level 9: magnetic variation
Use Calibration Level 9 to input the level of magnetic variation present at the
boat’s current position.
• -ve variation = west
• +ve variation = east
The tiller pilot transmits this value onto the SeaTalk bus, so it can be picked up by
other SeaTalk instruments.
Calibration Level 10: heading error correction
Use Calibration Level 10 to switch on Northerly or Southerly heading error
correction:
• 0 = Off
• 1 = Northern Hemisphere, 2 = Southern Hemisphere
You might notice that the autopilot tends to be a little less stable on Northerly
headings in the higher latitudes of the Northern hemisphere (or Southerly
headings in the Southern hemisphere).
This is caused by the increasing angle of dip of the earth’s magnetic field at higher
latitudes, which has the effect of amplifying rudder response on Northerly
(Southerly) headings. This error affects all magnetic compasses and gets worse
further away from the equator.
With heading error correction switched on, the tiller pilot can compensate for this
error by automatically adjusting the autopilot gain (depending on heading). This
will provide precise course keeping on all headings.
D3263-2
North
without
compensation
North
with
compensation
81130_5.book Page 63 Wednesday, June 15, 2005 3:48 PM
