as already mentioned , i would remove all plugs in water system,
or you could do the light for heat .

I remember reading on this site abt a guy who stored on lift and relied on a bilge heater of some sort. Big ice storm hit. Power went out and he couldn't get to the boat in time due to roads being impassable. 3 cracked blocks.

I would drain it and sleep well.

^ this...its not hard to do....why risk it?

Ive even put ball valves on my drains...I drain it every time I pull it out of the water since I get sent out for work on less then a moments notice.

4 plugs, circ hose, raw water pump hoses, 5 minutes.

Anyone use a heating pad...like you use when you have a sprained back?

Ask 92nsx ( Rob ) how the heating blanket worked for him..........

I will reach out to Rob BUT don't leave me hanging :-)...what happened?

The blanket caught the boat on fire, lucky he didn't lose the shop

Wow...that seems like a rare occurrence...maybe I'll just go with the shop light idea.
I actually thought about putting the heating pad on the outdrives and allowing the heat to "conduct" into the engine bay.