Agree with the comments about protecting the zipper across the top.
I modified the cover so I can now disconnect the zipper at the aft end
so as not to damage it when reefing.
On the leading edge of my sailcover I got tired of fighting with the
zipper (which, incidentally, should be attached so it zips bottom-to-
top and not top-to-bottom, IMO). Replaced the zipper by sewing-in a 2"
Velcro strip top-to-bottom and also sewed-in pockets for 2" flexible
plastic 'battens' on both the flap and the fixed part directly under
the Velcro. It now takes only a couple of seconds to securely close
this opening.
FWIW,
JoeS.