Therefore I believe my earlier statment is correct Vertical Load based on facts
I'm afraid not. the sponson is made up of three parts. the forward sponson, where the raft is, fuel tank section in the middle and the rear sponson where the main undercarriage is.
The middle section has fusable mounts like an engine pylon on fixed wing jet, allowing it to break away fron the front and rear parts taking the fuel away from the occupants in a ditching and hopfully not rupture in a crash landing on land. if you look at other clearer pics of the sponson taken fron the other side you will see the forward (and rear) sponson still attached to the fuselage. with the raft container empty.