Tony,

The stringers you mentioned are common in non-airboat applications, but like Buster, all of the aluminum hulls I've seen that were "built to be" airboats used the upside down T stringers.

Don't really know WHY. It may be just because it's easier to attach rigging to.

BTW, Chuck has shown me an example of the fiberglass transom trailing edge trick that Buster mentioned. I've NOT seen before and after results myself, but the idea sure makes sense. Chuck swears by it, and I believe him. One day, I swear that I'm going to try it myself...

I won't steal any more of his thunder, you need him to explain it to you.

Duane