Thanks for advices.
The yacht is Fuji Ketch 32. I think the Raymarine XmartPilot X-5 autopilot I purchsed can be installed on the yacht's rack-and-pinion steering wheel. The problem is that the shaft of the wheel come from aft. I have to install the motor tube of the X-5 autopilot to aft direction. My concern is the instrumets of the X-5 will indicate port or starborad correspond to the direction fo the wheel roated.