Zing
Well-Known Member
We usually fit one as soon as a roll takes pressure right off the sail and it looks like the wind might possibly get behind it in a bad roll. Or always if fairly deep downwind.
We had an accidental jibe going at about 150 degrees. It was very rolly and the autopilot decided it couldn't cope and switched itself off. It was at 2:00 am with a half asleep watch member, who didn't react in time. We got backwinded on the main and were pushed right through the wind to do a 360. There was a fair bit of crashing as the boom stretched the preventer (a thick polyester sheet) and bashed between its limits during the process. We rolled an awful lot too throwing crew out of bunks. No harm done luckily, but I do think a less stretchy preventer would have prevented the crashing. I don't think I agree with the suggestions here for a springy preventer. Apart from it worsening the crashing as it stretches it will risk the boom smacking a shroud and if that happens the boom is at risk and maybe even the rig.
Also, I think it important to restrain the boom at the end. That way if it does dip into the sea there is far less bending load on it compared to if it were attached further down. With a strong and stiff preventer the boom end should be able to touch the water a bit without it snapping. Best avoided though.