PVC fabric doesn't like being glued around compound curves - Fact.
Last weekend I managed to get a patch on the rear corner of one side of the deck, which was a pig to do as it involved trying to glue the patch over a compound curve.
In the end I cut some darts out if it and hoped for the best.
I used the Grey material instead of the correct off-white colour as it is much thinner, and coped with a small amount of stretching and compressing unlike the thicker correct colour material.
I pumped it up Tuesday evening and it stayed up OK until today, but I decided it would be best to add some mechanical strength over the top in a true 'belt and braces' fashion.
First images are the initial patch that sealed the cracks in the top surface, and the leaks along the seam made brittle by petrol leaking on it.
The final pic shows the strengthening piece added over the top, and the start of the patch on the other deck half.
The strenghtening piece is mirrored underneath.