Kim, I've followed some of your posts on your "unique" situation. Being that far North what are your "minimum" low temps.? Doesn't the water in the marina freeze over from time to time? If so, how thick?
Steve, we have been at the marina for 12 yrs now and the water in the slip has never froze over. The temps can get down to sub zero. But the surface temp doesn't get below freezing. A few times over the years there has been some ice on the shore line. I know this doesn't make a lot of sense but it has been explained to me that do to the depth of the lake, and the water "turning over", it doesn't freeze. The deepest part of the lake is about 1200'. In fact, the US Navy has a facility in Bayview where we are at. They do acoustical research with scaled down submarines. The largest sub is 100' long.
Here is the Navy's weather info site
http://lpo.dt.navy.mil/ . It makes sense when you see the water temp down deeper. I am sure some guru knows the technical terms for all this.
The only people that pull their boats are the one's that are at our seasonal finger of the docks. This area is closer to shore and shallow, so it can and has froze over. I am glad I don't need to pull ours out every year. And happy that we can sail year around.