I have since 13 years a 50', 1924 built Colin Archer sailing boat, with 2-2,5" oak hull and oak frames. This boat has always been lying in the water and ice and has been in 10" ice and pressed against the concrete quay when I wasn't fast enough to bring it out a yard before the ice froze. Never any problem whatsoever.
Our little 22' sailing monohull
was kept in the ice, beside a free floating pontoon mooring
with no problem, except a little loss of bottom paint
just beneath the water line, just as your experience, Sandy.
That is my own experience, but as for a multihull
I am concerned about the ice being able to make pressure between the two hulls, trying to separate them. I am not worried that the hulls actually will separate, but just that the forces can make damage to the bonding structure.
I am about to (if everything works out as planned) to buy a 47' epoxi cat, and that will mean that I have to decide how to do in the winter. Fortunately at the moment my mooring
is by a quay in a small river in the middle of town, where there mostly isn't any ice. But I always want to prepare for the worst, so I don't get any negative surprises.
So, has any of you had any bad experiences from boats in ice, under ordinary circumstances, or is it only positive?