I still have an Autohelm
1000 for my tiller-steered 33 footer. Works like a charm, except it eats a fair number of amps and can be overwhelmed in some conditions, even on "rough" setting.
I usually only use it when head
under power or when motoring in dead air or motorsailing because I'm trying to get somewhere in a weather
or daylight window.
Obtaining the correct course entails enthusiastic fiddling (no GPS
hookup, obviously); however, once set, there is very little wobble off course...perhaps two degrees over an hour as per GPS
I salvaged a chucked one a few years back in the hope I could cannibalize parts
if I ever needed to.