Our biggest boat was a 28' pontoon that had once been run over with a 25 horse Mercury. Really. Story for another time.
Anyway, it tended to deflate at inopportune times, an embarrassing disappointment, always.
We had tried various fixes; patches, replacing entire sections, and duct tape. Even an odd sheath that never did fit tightly.
Finally, we discovered Viaggaccoro.
With careful timing and precise dosages we were most often able to keep the tubes stiff enough to finish the job, that is if the river lady was cooperating and not being too ugly.
The only side effect was that the damn tubes got kind of fuzzy. But, that is another story.