There was no mention of the boat being left in the water over a winter. Given that, Jeff''s point of it being a risk is correct. However, I have left a boat in the water with below the waterline cockpit drains for many years in Alaska. Our harbor is full of boats like that. In my experience rubber hose doesn''t split if it freezes - it expands slightly then contracts when the water thaws out. I always wrapped the drain lines and seacocks with electric heat tape to keep them warm as an added precaution. Granted there could be a prolonged power outage at the same time as a very deep freeze. If you want to avoid all risks of sinking better pull the boat. I have seen boats sink from seacock problems but it''s always the same stuff - a seacock eaten out by electrolysis or an old rotten hose.