Interlux makes a "cold tar expoxy" .I used it on my aluminum hull and it was a great barrier coat.The name if I remember correctly is Bitumastic.This was a very long time ago so Im sure the spelling is not accurate.Gallon cans mixed with a hardener made a plasticlike coating.You can apply it as thin or as thick as you want.Works best on hulls with little to no flex.Highly recommend if it still exists.When buying it I was told that the US parks dept used it on their boats.Charlie
