I live in Houston and it really only get's below freezing about 15 nights a year w/ the absolute low being typically around 20. I have heard from others in this area that they have never drained their block and the boat is fine. I'm not ready to go that far but am considering using some block heaters instead on winterizing. Anyone ever done this? Opinions?

Here are a couple of the options:

Let me know what you think.