A friend told me of an old Boston Whaler used as a yard workboat. At the
end of the season, this was the last boat in the water, used for all kinds
of chores, including breaking/moving ice.

After serious ice duty, they lifted the boat out on davits (or crane?). The
bottom simply peeled away, where the ice had cut it, leaving the foam core
and liner intact.

It makes a tremendous difference whether you've got salt- or fresh-water ice
(we get both kinds). Salt ice is relatively soft - like rotten wood, at
worst; fresh is much sharper and harder, metallic.

Epoxy/glass holds up well in salt ice, but fresh will cut right through it.

....
I read a story in a Swedish boating magazine about a near disaster with
GRP
hull.
It was a smaller open powered displacement boat. I think the english term
i
double ender ?
Anyways, going through quite thin ice the boat started to take in water.
Turned out the ice had
cut holes on both sides of the bow. I guess the bow itself vas to thick.
Some rags reduced the
flow and he could reverse to shore!

/Lars J