I replaced my old zipper with a new plastic one.. its great.
When I rang around the various canvas/tarpaulin and camping repair places they were all going to charge me an arm and a leg..... ended up using a sail repair shop in rushcutters bay (Doyle Fraser Sailmakers 9361 4836).
They did it straight away for me no waiting around and only charged me $50.... you may need to detach the original zipper first as that will save them time & you the dollars for getting them to do it. I just turned up and used their tools to pull the zipper out... they have a range of zippers for marine use and only charge you for stitching it up.
They also gave me heaps of decent sized off cuts of x ply mesh to fix sails (for Free !! !) if they ever get punctured.


