I have never tried Natty Light, Kracker. I nmust have found about fifty empty cans in the stringers, some of them i dont know how they got where they did.
Here are a couple pics of the gas tank. You can clearly see the hole in the close up. Notice its only corroded where the foam was.
I linked a website on a thread here a few months ago about the harm of foaming gas tanks in. Give me a while to find it.
Found it;
www.yachtsurvey.com/fueltank.htm