I suppose if you were to do some more solid construction like bolting the cardboard together, sealing the edges (inside and out) with tar, and then reductaping the thing together again, I think it should float fine. You should try a trip down the Colorado River with a buddy or two. LMAO. Just be prepared to "jump ship" should you need to. JK, but seriously, you see what she can handle with some cheap upgrades.