a part at a used boat equipment store that fits my autopilot, I buy it. Yes, I have a few spare course computers for my vintage Autohelm 6000 (circa 1985). I have a spare compass - I have had one go bad so I carry a spare. I have spare control heads. I have a spare drive motor. I used to carry spare gears for the type 2 drive - the main gear used to be made of plastic and had a useful life of 6-10 thousand miles, now they use a bronze gear.

I just got back from five weeks cruising the San Juans and the Georgia Straight and had the ring gear in one drive fail. I replaced it with the spare drive. I am having difficulty getting Raymarine on the phone to get a replacement part - probably time to buy two.

I had so many spares at one time that I put together another autopilot and sold it.

My newer S3G based system has no spares. That is why I wired a changeover switch to go back to the old one if needed. The S3G control head failed after less than 24 hours use. It took Raymarine a month to fix it and return it while I twiddled my thumbs in Curacao. When it came back the course computer failed within a few hours and we sailed on to Panama on the old A/P. They managed to return the repaired unit to me fairly quickly in Panama but it took a lot of phone calls to get them to expedite it. This is why I will never buy a Raymarine piece of shit again. Now when you call them you are on hold for 20 minutes and then have to leave a message. It took three tries before I got to talk to someone and he gave me an obsolete part number - back on hold again - still unresolved. Lousy quality control. lousy service.