I have the hood seafurl on my boat and just replaced the furling line
a few days back. The previous owner had a 1/2" inch furling line
which would jam up the can. What you need to do is furl the sail up and stow it. At this point you can see where the stopper not is tied in the can. There are 3 vinyl screws at the base of the can on the stock pole of the roller furling
. Unscrew them (carefully since the sun had worn mine down and one cracked). The can cover should now drop down u can now untie the stopper knot remove the old furling line
and add your new line
. Just make the stopper knot small so you can slide the can back up and put screws back in. Let me know if you have specific questions.