I keep hearing people mention draining the mufflers. I also wonder if any boat has sunk because of a muffler failure or freeze up. If you close all the seacocks, you may think you wont sink because you closed all the holes in the boat. What about the underwater exhausts? They don't have seacocks. How can you drain the mufflers if the boat is sitting in the water? If you run antifreeze through the raw water once it hits the waterline in the muffler your antifreeze has the same freeze point as salt water. I guess it would have to get pretty cold in the engine compartment for salt water to freeze in the muffler below the water line.
