Again, thanks for all the inputs.
Mike (in Mexico): I hydraulic AP, in the sense I'm talking about is a
pump that goes inline into my existing
hydraulic steering system. It turns the
boat by pumping hydraulic fluid around in my system via that
pump, rather than via me turning the
wheel.
I guess the hydraulic AP is probably the way to go, but the "single point of failure" thing still has me a little unhappy. I do have an
emergency tiller, but like most of those, it's no fun to use. You have to be in the
engine room! Not fun...
Maybe the right thing to do is carry a spare
steering system when crossing the ocean. A little extra copper tubing, a ram and a
steering wheel pump.