I scrape bottom from time to time and if you're fishing a shallow river it's to be expected.I think pontoon shape has alot to do with it.I have a outdoor eng versa vessal and have done a few floats without any damage to the pontoons.If ya try and go against the flow you will just wear yourself out.We always have a couple trucks at the take out.
What river did ya float?I haven't done one this year(the flows were too high for most of the summer).
You should do the delta(you can go against the tide in most areas)it should start picking up real soon as well as the striper action.
Swampy