I have a few extra control heads and I think, one compass. I"m short on the course computers. The issue with these units is that there were as few generations that look the same but are different. I would need to know the part number on the course computer to know if I can help. The number probably starts with a z. The label is on the edge of the course computer where it connects to the terminal block. If you do not know how to remove the course computer do not try.

I also agree with the comments about the chain drives. But there were two generations of the drives with different clutch arrangements. Depending on the age, you may still be able to get parts for these. They are the same basic mechanicals at the linear drives (to a point). They are selling the same drives today (with different motors and better gears) as they did starting in about 1985. Prior to that they were not as robust.

If you could take pictures of the course computer, control heads and drive that would also be helpful. My email is systormalong %%% at %%% yahoo %%% dot %%% com.

You said you sail the Great Lakes. Are you in Chicago. I am originally from Chicago and visit there a few time a year..