I had a similar problem on the foredeck of a previous boat. In that instance, I drilled several holes throughout the delaminated site and let it sit a few days (she was on the hard and I had a few days of nice drying weather).
I then went back with a bent nail in a drill as if I was going to rebed a deck fitting. Then filled the holes using West system epoxy and glass threads. Once dry, I sanded the epoxy/glass. Had to repaint the deck and used filler in the paint to match as best as possible the deck pattern. It was not bad, and you could see it if you were looking for it. But it was solid again and it didn't leak.
Good luck.
Ed
Hope that help