[paulmcquillan]

is it the existing auto pilot control head that is non-functional or the below decks rotary drive mechanism that is not working?

(or did I mis-interpret, and you meant the existing unit is a wheel pilot)

There are some mfgs who say they support the replacment of a failed autopilot control head and reuse of a below decks rotary drive mechanism.

That particular change is still three down on my own 41''s list of projects, but I have two dock neighbors who like the ComNav heads they have installed. My existing rotary chain drive below decks seems to be plenty tough after three years of experience with it. Access and maint are certainly easy enough, so reuse is high on my list.