Avoiding freeze-ups while towing in very cold weather?

time2roll, that was a great link to your recirculator project! Unfortunately, some of the photos have died, probably when photobucket kicked the bucket.

And I see some folks addressing you as smk -- I won't use your full name. But I did not realize until now that you are the same person who used to be known as smk!

If I could engineer a way to use my water heater as a heat source for my pipes and tanks while in transit, that would be much more efficient than running my furnace and heating the entire cabin.