Ideas on patching a failed DIY project??

Hi guys,

About a year ago, as I was packing up to leave oz, I hastily installed a POV cargo fly (see link below). This served me well for the year, however gradually started coming apart until The bottom corner leaks air like a seive. To stick it back on, I have tried aquaseal (peeled off), tyvek tape (eventually peeled off) and now this evening I tried the patches alpacka sells, however these do not adhere properly.

I feel like the reason the zip is pulling off is due to its stiffness (similar to that of a beefy tie out patch) as compared to the surrounding fabric. Each time I fold the boat, the zipper is trying to sheer off.

I am running out of ideas to fix this (I feel like I have exhausted all of the easiest ones) problem and here are the solutions left on my list:

a.) Try and seal the zip onto the boat using a flexible strip of urethane coated nylon
b.) create an internal flap which drapes over the zipper, hopefully sealing the zipper shut when inflated
c.) cut the zip out and treat the gash as a big hole (in which case, is there any way to remove that 2 part urethane glue?)

Anyone have any suggestions?