in mast furler
I have a z spar in-mast furler on my 1996 Oceanis 281. When I first purchased the boat, I too had some jamming problems. One issue was that the out haul and furling lines had been oversized by the previous owner and this lead to jumping the tracks on the furling drum and getting stuck. The correct diameter lines solved that problem. Getting the sail creased when it is furled is pretty common. Keeping tension on the outhaul while furling helps with that. Keeping the main halyard pretty tight also seems to help on mine. As you stated, your problem is that the sail is stuck because of the creases that developed the last time the sail was furled. You might try: Pull/winch out as much sail as you can. If the crease is low, go to the mast and physically pull/jerk downward on the leach with your hands. Pull hard but be careful because if it comes out, you'll fall. If the jam is up past your reach, go out to the aft end of the boom, loosen the topping lift, keep tension on the outhaul with a closed clutch, and jerk downward hard or hang/ bounce on it. If you don't weigh much get a bigger or second person. I wouldn't worry about tearing your sail. If it tears, you probably needed a new sail anyway. Be careful here too because when it comes loose, the outhaul slide will move aft rapidly and can get fingers if they happen to be on the track. It is also possible that improper furling in the past has actually created permanent creases (almost like they have been ironed in). I sent mine to SailCare for cleaning and it came back without any creases. Good luck and once you get it out, keep trying different line tensions on traveler, mainsheet, halyard, vang, and topping lift in the future to find out how your sail furls and unfurls the best. Mine seems easiest when on a starboard tack because the sail seems to have a cleaner entry angle into the mast.
