As a new owner of a 170, I wasn't sure how to cover it for the Michigan winter. I had read that I should avoid a dark tarp, which I did. I drapped the tarps over the mast which was horizontal on the crutches provided with the trailer, then loosely tied the tarp along the bottom of the boat (as I had heard one should not tie it up tightly), thus covering the whole boat. Unfortunately, we had a heavy snow followed by a thaw then a hard freeze. The people where I store the boat called me to say that a large mass of ice had formed on the tarp. When I got there, I found a LARGE piece of ice (I am guessing in the 400-500 lb range)weighing down the tarp on one half, such that it caused a bow in the mast, two of us were unable to budge it. Last week we had a thaw which melted about half the ice and I was able to break it up to remove it - fortunately, the mast now appears to be back to straight. I rearranged the tarp to allow better runoff and will keep checking it over the winter. The dealer thought that someone made a proper boat cover for the 170 but was not sure where to get it. Any ideas? Should I make some sort of rib structure to support the snow load? What have other people done?