I purchased a can of the proper repair glue for about au$32. and noticed it smelled like the plumbers glue used on retic pipe. Next time I bought plumbers glue for pressure pipe for less than au$5 thinking, worth a try.
I had a small leak below the water
line. On a 20nm leg, I used the glue with a coin size patch on the inflated dinghy
up on deck
. Held it in place for maybe 10 minutes and it is still good today, 12 months later. I think my inflatable
is hypalon but bought second hand I can't be sure.