Sail balance is very important with Autopilots, particularly Wheel
Pilots, an unblanced sailplan can lead to excessive weather helm
which can cause an autopilot to work beyond its design specification, this is one reason why Autopilots are over-rated for boat size when specified. I know of a Hunter
30 fitted with a Wheel
Pilot system that wrecked a new wheel drive within 250 miles of first use, it was determined that Weather Helm
was a significant factor in the failure.
Originally Posted by Zanshin
It is also a matter of sail balance - the better your boat is balanced, the less effort your autopilot needs to use in order to hold course and the better it will work. Autopilots can and have been used to cross oceans, never being turned off.