Read Your Insurance Policy "Exclusions"
I'm not far from you in the West River. I sail thru December every year and winterize after Christmas. Water tanks, holding tank, head, engine, all the usual stuff. Every winter we do get a bit of ice for a few weeks and it's not thick. Myself and three others around me all have bubblers so we're OK. I do think Warren Millberg makes a good point that bubblers are only as good as the electric that runs them. If we get a bad storm and power goes out for a few days we could have a problem but it's one I'm willing to risk. I haul every year for a week or so and do the bottom, etc. My reason for this approach is mostly to save the money.
That said read your insurance policy. If you happen to have State Farm as I do the policy reads:
"We do not insure for loss to the property described in Coverage A either consisting of, or directly and immediately caused by, one or more of the following: freezing, thawing, pressure or weight of water or ice, whether driven by wind or not".
Like Stu Jackson always says "your boat, your choice".