Re: Anybody ever reinforced their inflatable's transom?
It would seem to me that there are two possible issues-
If the transom itself is strong enough, but you want to reduce the strain on the bond at the tubes.
The Zodiac 470 CCRC has web straps from the top of the transom to floorboards Allows for the weight/torque of dual outboards. I had an old Avon in the early 70's and the transom was fully removable from the boat, but was rated for 50hp (way too much as we found out). It had metal braces that screwed into the top of the transom and into the floor to give it support.
The other is if the transom wood itself is not strong enough, like is being discussed on the Saturn X-Boat post.
For flex, you might be able to cut a piece of plywood or metal and secure it to the existing transom to make it more rigid. It might stop the flexing if the wood is the weak link but would not increase the stress on the bond to the tubes.