That's an awkward spot to patch, but rather than dismantle the dinghy
, which will be a real sack of worms, and imo better avoided, I'd suggest using lightweight hypalon, make a 2" in diameter (~ 5 cm) circle, and glue it over all. Jim used this strategy for some of our leaks
in one of our old hypalon dinghies, and it worked quite well. Our glue of choice was SC2000, conveyor belt adhesive
. Currently SC4000 is available, which has slightly different volatile thinners. It worked well below the waterline, too. Mask the area, so you get a tidy job.
Using a ball point pen, draw around the circle you have cut out. Carefully and thoroughly sand the surface, also sand the surface that will be glued on the patch. Combine the 2 parts
of glue in a small container. Clean the sanded bits with acetone and a rag to remove sanding
dust. Mask the outside of the circle. Paint
the glue on, and let it dry till almost slippery when touched with the fingernail (the broad part), then the 2nd coat, and, when it's ready according to the directions with the glue -- using waxed paper between the two, start the edge of the circle, then move the wax paper bit by bit, and keep working the circle in, till it is all glued, and you have the waxed paper. Jim used the backbone of his pocket knife to smooth and pressure the patch. You can put enough air back in to make it home to the big boat
, but leave that tube slack over night, then inflate to full pressure.