We had the good fortune to meet a man in New Zealand
who loved and repaired hypalon dinghies. What he told us is that the humidity for gluing them is critical, or the lack of it. He was going to rebuild
our 13 footer, to keep his 15 footer, from the Rainbow Warrior company. [Life's amazing, isn't it? :-D]
It turns out now, that nowadays, all dinghies, except for welded PVC, are glued in temperature and humidity controlled situations.
If you try to repair a hypalon dinghy, in a humid climate, the glue is likely to fail, if you use Bostik. If you use SC 2000, and allow it to cure properly, that bond will last, and it's find under water
. I have no experience with the SC 4000, understand it doesn't use methyl ethyl ketone and the 2000 did.
With the difficulty nowadays since Du Pont isn't making it any longer, is that the various so called hypalons are of different weights, and the lighter weight ones are more susceptible to abrasion damage, hence dinghy lifetimes are not as good for some as for others.
If you meet a knowledgeable dinghy repairer, they may be able to source good quality hypalon for you. It isn't easy.
Dockhead, Swift, in Australia make a number of hypalon RIBs of good quality. Their heavier weight than their Gemini competitors is because of their use of the heavier hypalon. Bombard made a black hypalon one for use by the French Navy. We know a couple that bought one, and raved about it. It's only an "n" of one, but I think there are still some good ones out there, it's just going to be a real caveat emptor kind of situation.