This is a subject which has interested me greatly since some friends suffered an accidental jibe running at night along the notorius Pt. Conception (CA). They had failed to reef early sailing downwind and the jibe occurred in about 40 knots. They were using the same kind of "prevanger" (Lines on either side from about midboom to chainplates and back to cockpit) that I was using on my boat at that time. I had never really thought too much about the compression
forces on the boom and gooseneck should a jibe like this occur. Their boom-gooseneck- mainsheet system sort of exploded with multiple failures! The wood boom was shattered in two places! Good thing nobody's head
got in the way. On my own rig I used braided nylon for these lines for some shock absorbtion, by I think this could make it even worse by letting the boom make it further across resulting in an even more extreme loading angle on the boom when it did fetch up. I don't know. But I started thinking you really need a better way. I tried a boom brake
(Walder), but had some issues with it. You adjust the tension on the line through the brake to adjust friction, but it changes adjustment as soon as you changing sheeting because the full lenghth of the brake line circuit changes as the boom angle is changed, if that makes any sense. Defender had a good deal on the Whichard "gybe easy", so I now I'm trying that. It's a friction device like a mountaineering belay device, and using it with the special line that provide it moves very smoothly. It can be set up in different configurations to vary the friction. I found it needed to be in the highest friction setup for jibing my main (about 450 sq. ft.), and still came across pretty fast. I did this test with the boom let far out and a following wind
of about 15-20 knots. With this much friction, you can't sheet the main in withou reaching up and repeatedly freeing up the line in the friction device-pain in the ass. I'm going to play with it some more. I'm thinking it might be worth it just to put on when your'e in a someswhat dicey running situation, and take off most of the rest of the time. You can take the mid part of the line off the friction device whilst leaving the rest of the setup intact. I'd be interested in hearing about people's experiences with the Dutchman boom brake
. Another approach that might be considered is the use of a device such as the "screamer", a climbing device made by Yates. It consists of webbing sewn to itself in a series of accordion folds. Each fold breaks open at a predictable loading, so you can absorb a bunch of shock loading and still have the connection intact. It's designed to minimize the loading on a questionable climbing rope anchor
when you fall on it (yikes!). Another wrinkle-some people recommend leading a preventer up to the bow, allowing (they say) the boom to rise if it buries in a wave. By the way the couple who suffered the gnarly jibe patched up their boom and gooseneck and headed south. They've cruised Patagonia and rounded Cape Horn with no further serious problems.