i started with a long reply and got interupted.
If you secure a tennis ball to some webbing and duct tape that to the
inside of your cockpit , leave a trailing end out to the outside of the
cockpit taping it the you will have the same effect without damaging
the hull..a fast tug will pull the spray deck up and away from the
cockpit. i have a very good friend that had an identical problem with a
capella ( mine ) . the grab loop was tucked inside the cockpit ( big
oops ) and there was a cold water upset amongst rocks. he opted to bail
, mistake # 2. both boat and my friend were fine.
a tennis ball and webbing is less invasive and works better than a
fixed strap. it is an emergency only thing ( one use ) but works well
in classes too. i see you teach, so does my friend. he has this taped
this arrangement to a couple of his boats that may have tricky cockpits
and combings.
good luck cc & m
fiona.