Figuring out how the rear, main weight bearing pontoons will attach, provide buoyancy and have clearance while also being rapidly deployable has required several days to work out. I believe I'm closing in on a good solution.
We built a pair of pontoons over the weekend. Now I'm looking at the overall scale and volumes, while finishing designing how the flotation rigs to the vehicle. Things look fairly promising at the moment. Everything's new, fresh, unsullied by mud and lake weeds, and the problems have been surmountable.
http://youtu.be/p4MicFCr9Ow In which we take a ride on our amphibious "date trike."