Does anyone have practical experience using a consumer grade digital
camera with high zoom and Image Stabilization on a sailboat (taking
shots of distant scenery or other boats)?

I am considering purchase of a newer camera with 10x or 12x zoom to
replace my 3x capable camera. It occurred to me that Image Stabilization
might be a good thing at these high zooms.

I am considering cameras like the Canon S1 IS, Konica-Minolta Z3/Z5 or
Panasonic Lumix series.

While I read reviews that I.S. really helps remove a bit of "shakey
hand", I am now wondering if the movement on a boat would be way too
much for it and it might over-react giving a worse picture than without
it. (Of course I could turn the I.S. off in this case but if I can't use
it I wouldn't want to pay for it and add that complexity to the
camera, as it is one more point of failure.)

If anyone has used such a camera on a boat, I would love to hear your
comments.

Dave