So I am almost ready to head to Elk Camp this year. We hunt from a local resevoir and have to boat in to our camp. We moor our boats and hike up the hill to our spot. Small mouth fishing is fantastic. This year is the first year with my big boat. I have a closed cooling system. Looking at the forecast the lowest temp is 23 on one night. Do I need to drain my exchanger before bed each night? How about the outdrive....Down?...or up, but still in the water?