I bought the XXHeat 450W for my 24' Chaparral Sunseta on Lake Lanier so I could take the boat out on great days in the winter. No need to winterize. The heater works great. Just cover the vents and plug it in. Everything else takes care of itself. The design and reliability of this unit is top notch. The unit is designed to turn on at 40 degrees and off at 55 degrees and keeps critical components in your engine compartment warm and protected from freezing. Highly recommend especially in relatively mild weather areas like Georgia where there are plenty of days in the winter season to enjoy boating. Steve at Xtreme Heaters will take great care of you for all your boating/heating needs. Thanks Steve!