Free: Contests & Raffles.
Ok, scratch what I just said. I was thinking of pontoons on the side to stabilize and add floatation
Those backwater pods look a lot like Beavertail pods, if you google them, there was a person with a video who used 3M 5200 on a 100% fay surface seal and proper prep. After cured, it shows him jumping on them, and they do not come off, might check it out as a way to leak proof your installation. Good luck