My 25 footer sits in the Columbia River at my friend's boathouse, with a
significant current under it. This winter, I haven't been concerned about
winterizing it, since it has fresh water cooling, and even more pertinent,
daytime highs have been above freezing.

Starting tomorrow, highs will be 28 degrees through Saturday. I have a
covered hallogen light that can be easily placed in the bilge, near the
water tank. The power source is reliable. Will that do the trick or
should I drain the water and apply antifreeze? I'd prefer not.

-Greg