Hi Adrian -
I've been looking at bigger pontoons lately as well... amazing how they can be 'tricked out'.
With larger pontoons, powering by flipper is not really practical IMHO. I find even the smaller ones marginal at best to move with flippers in wind or current. I could be wrong, but they are really oar-driven devices. A small motor would be a good option.
I have the Bucks Bag Bronco, very nice transport vehicle for rivers to class III and short sessions on the coast.
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