Wind damage to rolled jib

[Jim Cate]

Originally Posted by Kettlewell

If your boat stays head to wind it is not likely to happen with a tightly furled sail. When you head off the wind is when the wind can gain some purchase under the wraps.

Hmmm.... since the wraps spiral around the stay, making many 360 degree turns, how does the boats heading affect the chance of wind getting under a wrap?

Jim

[Kettlewell]

Hmmm.... since the wraps spiral around the stay, making many 360 degree turns, how does the boats heading affect the chance of wind getting under a wrap?

Wind blowing from astern gradually loosens the spiral. Wrap a triangle of napkin around a pencil, holding it at an angle like the forestay, and play with it a bit. The wind will gradually penetrate the spiral from astern, aided by the angle of the forestay.

[chrisr]

Originally Posted by Kettlewell

Wind blowing from astern gradually loosens the spiral. Wrap a triangle of napkin around a pencil, holding it at an angle like the forestay, and play with it a bit. The wind will gradually penetrate the spiral from astern, aided by the angle of the forestay.

that's actually a good point (i think). the angle of the forestay could make it slightly easier for wind coming from astern to get into the spiral

fortunately such rarely happens at anchor...

cheers,

[Kettlewell]

that's actually a good point (i think). the angle of the forestay could make it slightly easier for wind coming from astern to get into the spiral

It's why it is harder to get a tight furl when you roll up the jib with the wind behind you. The wind keeps blowing into the spiraled jib.

[sailingharry]

Originally Posted by Jim Cate

And when not on passage it means that tacking or gybing the Genoa requires rolling it up... a real PITA in restricted waters like our present cruising grounds (SE Tasmania).


Jim

Jim,


As a fellow sufferer, a tip to share. For us, at least, the big jib is fairly easy to GYBE. Point the boat downwind, it billows in front, and you can pull it back through the slot between the stays. Very similar to an asym "inside gybe." Sure, it costs a few hundred feet to leward, but as a cruiser that's no big deal. In tighter waters, we go to the small jib regardless of wind -- and since it's a self tacker, tacking the boat means turning the wheel! Short tacking up a small river is almost embarrassingly easy.

[caffel]

1. Is it time for maintenance on the upper swivel?
2. When there is warning, and there's littlte chance the sail will be needed, stand on the bow pulpit and frap the jib with webbing.

[clakiep]

You need a decent cut jib and two separed winsches to furl or unfurl a furling jib in strong wind ! Happened to me in the South-Atlantik on the way from Rio to Southafrika/Saldanha Bay. Wind picked up at night to 45 Knots. Wanted to furl in the jib. Slaking the sheet without tightenig the furl simultaniosly made the sail and sheet flutter so violently that it riped out the sheethorn. Than of course we could furl it in. But it unfurled by itself many times, than shaking so violently that we could anticipate the forestay braking and the mast coming down. We managed to unfurle it and take it down. It was the only jib we had on this Dean 400 catamaran we were delivering. We spend the next two days repairing the jib sheethorn, making a sandwich with several layers of fabric, glue and stiching - each stich hammering the needle in and pulling it out with pliers on the other side. Avoiding to much tension it holded !

Capt. Claus - ocean tramp and delivering capt. 20th century

[Traumerei]

Especially with older sails,where the leach may have stretched, it’s important to move your jib cars as far forward as possible before furling your head sails. This ensures that the furl is tight along the full length of the leach as it raps down the furler.

If this is not done the foot of the sail will be tight but the leach, especially toward the top, will be loose. In strong winds pockets form, stretching and pulling the leach tighter above and below the pocket that acts like and air scoop and as a result becomes even larger. Eventually, the pocket, battered by strong gusts. Will tear and then over time destroy the sail.

[Markhunter1097]

Apply McLube Sailkoteplus to the sail, it will furl 30% smaller, not my stats but McLube themselves state this. This should help the unwanted unfurl, if not prevent it

[OneBoatman]

A couple of things come to mind. One is the upper swivel has to be in good working order. I use clear silicone grease to keep this bearing happy. Second would be assuming you have normal luff tension do not furl when off the wind greater than about 50 degrees or so as this puts higher loads on both the drum and upper swivel and the leach is less cooperative. Third would be if your rig has unusually low and high tension in the backstay low tension can distort the sail shape and can aggravate the way the sail furls. Conversely, high tension puts unnecessary loads on both the drum and upper swivel.

[billve]

After having my jib unfurl during a Chicago summer storm (where winds can top 60 kts quite frequently as the front goes through), I am a strong proponent of wrapping the jib with a spare halyard, usually my spin halyard. It's part of my normal routine when I return to the harbor, and I've never had a problem since.


Easy insurance for peace of mind!