raymarine autopilot, ST4000/S1

[chubby]

We have a 10 year old at least ST4000 wheel pilot, it must be old as it has the autohelm logo on it, it is geting long in the tooth, rattly and noisy and I am thinking of replacing with the new S1, which should be a near exact replacement however the info on the Raymarine website talks about the S1 needing a rudder sensor which would add to the complexity of installation, the old one doesn`t have this and worked fine without, is the rudder sensor esseential, anyone tried directly replacing the ST4000 with a S1, any comments or advice?

 

[hightech]

It will work much better with a feedback unit, but can be setup to work without one.