Boom brake/preventer

[jimg]

I recently sailed down the WA coast chased by a near gale, and I resisted using a preventer on my Beneteau First 38. I did suffer a few unintended gybes, but the main was double reefed, so they didn't seem that serious. Oddly enough, all the gybes occurred right after a watch change, so maybe I need to introduce a "warmup" time for the new helmsman! I acquired a climbing "figure 8" figuring I'd rig something for next time, and am still wrestling over the idea.

First, I know there are some large forces involved in a gybe, and it's not clear to me that any attachment point is up to the task. My 38 has a pretty beefy toerail, but I can imagine bending it. My single chain plate is also pretty overbuilt, but it doesn't have an easy attachment point, and a few thousand pounds to the side will probably induce some deck leaks. A dedicated pad eye is another less than ideal alternative.

Second, I was thinking of rigging the figure 8, then using a block on the boom to tighten the contraption (The Gyb'easys "alternative rigging"). I've read suggestions to use nylon line to get some stretch, but I have no idea what Gyb'flex is, and whether nylon is preferable to regular dacron braid for the actual bridal.

My inclination is to skip the whole thing and provide some sort of snubber on the mainsheet, so that a gybe doesn't break a block and throw the boom into the shrouds, leading to some sort of mast nightmare. On my recent trip, one of the gybes did pull the dead end of the mainsheet from it's pad eye (the D shackle loosened and opened), but as it was knotted, it just got caught in the boom block, lengthening the sheet by a few feet. Could have been worse.

Any advice?

[Ian McColgin]

Safe management downwind can lead to controversy. Most of my sailing is in traditional boats with long (by today's standards) booms.

Most preventers and even forward guys don't really have the leverage - don't go far enough out on the boom - to handle the stress. Either you tear one end off the rail or the other off the boom or you break the boom. If nothing breaks and you don't catch the gybe and get back on course rapidly enough, then the backed main wraps the boat around with singular violence.

So all in all, I'd rather risk a gybe than use a preventer or guy.

If need be, I'll tack downwind so that the boat's sailed more on a gybe-proof broad reach rather than risk the gybe. Better a little extra distance.

If sailing straight down wind really matters for whatever reason, whether the demands of a close race or the exigincies of obstructions, I try to get a relief helmsman settled in on a broad reach before resuming a dead run.

G'luck

[jimg]

Thanks for the input. I think I'll rig something with line that is light enough to break if the weather gets heavy and I forget to remove it.

[Ian McColgin]

Depending on the rig and the sail you often need something that's more in the line of a vang, holding the boom down, rather than a preventer. Confusion results when the two functions are confused.

Often the leverage for a vang that goes from mast to boom is just not enough and it makes sense to make a tackle vang from the rail out to the boom. This will act a bit like a preventer if you start an accidental gybe.

Problem is: If a vang is weak enough to break away in an accidental gybe it's not really strong enough to flatten the sail in any sort of wind. And flattening can be really important in keeping control, resisting excess weather helm, and reducing the chance of an accidental gybe.

If you must use a vang from the rail, be careful and don't accidentally gybe.

G'luck

[jimg]

I already have a soft vang and have a rigid vang being fabricated. The brake/preventer only has the one job.