If you have determined that Bombards are made of Hypalon VS PVC that is a start. (I didn't know).
The correct glue for Hypalon is basically "contact cement", sold in small tubes, from marine
stores. I used to use the superior two part version, but now use the one part, because it has many times the shelf life. (I have NEVER had a patch fail, with either kind, even after a decade!
The failure could have been: Poor prep... It needs several solvent washes, (with MEK), and the bonding surfaces ONLY need to be scuffed up with 80 grit, to a 100% fuzzy glaze. This is very important.
It could be an improper ratio of two part glue?
It could be the wrong kind of glue, like the kind for PVC?
Or it could've been incorrectly glued.
The correct procedure on newly prepped surfaces, is to coat the two mating surfaces which were masked off before sanding
with a thin even coat... QUICKLY with a throwaway acid brush. Then, after 15 minutes coat the two halves again. NOW, wait 5 minutes if it is HOT, or maybe 10 minutes if it is 65 or 70 F. Then put the two halves together one bit at the time, with PERFECT alignment from BEFORE they touch. Once they touch, it will not move! After the piece is on, press it VERY firmly over and over, until it is all bonded. This pressing and working it down process might take 30 minutes on a large part, and it can't be skipped or over done.
The largest piece I have done was a rub rail, and an entire floor would be a challenge! It would best be divided into perhaps thirds. You could coat and apply the front, then coat and apply the middle, then coat and apply the aft third separately.
IF you have the correct glue on there, and it feels dry, AND it was prepped correctly, then you don't have to remove it. You can just soften it with MEK, and start the bonding process as mentioned above. The new glue will soften and bond to the old dry glue. HOPE THAT YOU HAVE THE CORRECT GLUE ON THERE! IF the previous glue job had the parts
put together right away, that might account for the previous failure.
If this glue on the two parts dries to the touch, that is a good sign. I'd then glue on a small strip the way I described, and let it sit a couple of days. Then if it will NOT come off, you can probably trust that it was the correct glue. Next... prep what you can and re-glue, (After removing that patch).
After the strip experiment
, IF the prep or glue on the two parts still seem wrong, your best bet on removal
is MEK, but it would take a LOT of time and effort, and might screw up the hypalon layer. If this is the conclusion, however, you have nothing to loose, so go for it!
The way that you remove that strip, or a patch, D ring, oar lock base, rub rail, or anything else glued to it, is: Using a heat gun, held back 18" and passed back and forth gradually, heat the area. As it heats up, try to work
a sharp, thin putty knife blade into the glue joint. As soon as it goes in, grab an edge and start peeling it off, GENTLY. Don't pull hard if it stops coming, heat some more. The difference between getting the glue line to release, and melting the Hapalon coating, is about 10 degrees! Go slow, heat the piece overall and gradually, and DON'T over heat it by getting close or stopping the constant fanning back and forth.