One of my fears is having to manually steer on a long passage with only 2 of us. We recently made a 1,000 mile passage from New Zealand to Vanuatu. About 200 miles into our passage, The Raymarine Autopilot went to alarm status with a message "drive stopped." The linear drive unit had failed.
Well, I donned my "chief engineer" cap and turned the A/B switch to the Rotary drive unit...problem solved, but a bit noisy as you know.
Since arriving in New Caledonia I have determined that the clutch on the linear drive unit is faulty and slipping causing it to go to alarm status. I have decided to make the next 1,000 miles to Australia with only one drive (fingers crossed) because there is a Raymarine service repair facility in Australia:
Raymarine Asia Service Workshop
Suite 301, 2 Minna Close,
Belrose, NSW, 2085
As a side note, we met a couple on a Hallberg-Rassy here in New Caledonia who had the same problem about the same time as us, however their solution did not include an A/B switch, they manually steered about 800 miles.
Also we are acquainted with a couple who were sailing a very fast J Boat departing New Zealand several days after us; they were sailing to Fiji. About 300 miles into the 1200 mile passage they also lost their autopilot (cause unknown). Additionally they began taking on water near the rudder post (but never found the actual source). The J Boat sank within 2 hours and is resting on the ocean floor with all of their belongings in about 6,000 feet of water. They could not stop the water and had no way to compartmentalize the problem. Fortunately they were rescued by a nearby boat which we also know.
Sometimes we take A/B switches and water tight compartments for granted. I thought you would like to hear these stories.
s/v Bebe SM2 #387