I have been hooking Autohelm and Raymarine ST model controls to other mfg
actuators for several year. (my boat and helm demands are too much for
Raymarine/Autohelm drives).

I can't address your specific question but can advise that the amount of
current your BenMar draws should meet that normally supplied by the
ST60001+. Your manuals might tell you this. If not you will have to add a
drive transistor circuit that provides both forward and reverse power
polarity.

If your BenMar provided position feed back to the control, then that will
have to match the resistance ranges that the control unit is expecting and
if not, you won't be able to calibrate the rudder location without a
Raymarine rudder position unit.

I'm using a linear drive unit from Alpha and had to change the feed back
potentiometer in this drive unit. Not easy to find, but I finally did.

If I weren't a DIY Tinker', I probably wouldn't have a AP. Hydraulics just
seem to extreme for my open cockpit arrangement. (double ender Ingrid 5ft+
tiller)


--
My experience and opinion, FWIW
--
Steve
s/v Good Intentions