We learnt this lesson quite a while ago, DO NOT LEAVE ASYMMETRIC OR OTHER FLYING SAILS FURLED ON THE FRONT OF THE BOAT.
A while ago, whilst living in the UK on a boat, a storm came through and a neighbours boat had left their Asymmetric out up, furled on the front of the boat. Sure enough in the early hours the wind managed to get it unfurled and what ensued was life threatening as we tried to rescue not only the sail but the rigging with 60kts building from the side and 100’s of metres of light cloth flying from the mast.
Since then we NEVER leave the flying sails out over night and ensure when the wind envelop exceeds the sail we at the very minimum drop it onto the trampoline and secure it.
Yesterday we didn’t do this and quite quickly went from sailing downwind with the Asym, to upwind needing to reef and then before we knew it, we had 30+ kts, full sail and the Asym unfurling itself as we tried desperately to drop sail.