Scrap the Dumas boat and start fresh with something lighter.
I agree with Got RPM. I have looked at those kits and they don't lend themselves well to someone who wants the whole airboat experience. Most of those kits were stamped out over 30 years ago and have sat on shelves in shops for that long.
This is the reason i made my design. The dumas boats will not stand up to the running that i have done over the years.