Well this sucks, Thursday evening forecast in Rochester NY has us with predicted PM ice and a low of 23*. Being a few days away they don't have the hourly yet, but I have to assume it will be 3-5 hours at that temp and carry into the morning. The water the boat is sitting in is right around 48-52*, should we start to be concerned with low 20's? I'm not only thinking about motors and genset here, but even the fresh water systems. Last time this happened I went down at around 10PM and ran the engines up to temp to get some heat in there and ran the cabin heat to get that up to 60 or so, but the lows were only high 20's, not into the low 20's. I doubt we'd get much freezing in it overnight but I don't want to risk it