Garman chart plotter that you engage with a manual cable. When disengaged the auto pilot turns but the wheel is free to move. It did, however, failed to disengage once when the clip holding the cable came loose. I was leaving an anchorage on the Gold Coast and had to make a slight course correction while setting up my track and was pretty surprised when the wheel wouldn't disengage. I ended up setting a waypoint a couple of miles out to sea in the general direction I was heading and set the autopilot to track to the waypoint. I then went down below, removed the microwave and cabinet back to get access to the auto pilot and found the slipped cable. We were just cruising on down the road the entire time but it could have been a whole lot different. I was in a good position when it happened and feel even better now after reading Dan's post. I had plenty of room so I could have stopped the engine, dropped the sail and dropped the anchor and I would have been fine. I'd rather be lucky then good.