Preventer -- and an accidental gybe

[thinwater]

... And might you be better to run a snug (not locked down--hand tensioned tackle, not a winch) boom brake than a preventer? No, it would not stop and accidental jibe, but it would slow it to a non-destructive speed. Locking down a boom brake is a proven way to break a boom or snap lines and it is not recommended by the manufacturers (yes, I have discussed this face-to-face with the Waller brake designer).

What about a boom brake you only connect in conditions where you would consider a preventer?

Yup, some extra strings, but I would give it serious consideration for singlehanded passage making, since it is simple to use, no going on deck. Recovery is automatic.

[davil]

Originally Posted by thinwater

... And might you be better to run a snug (not locked down--hand tensioned tackle, not a winch) boom brake than a preventer? No, it would not stop and accidental jibe, but it would slow it to a non-destructive speed. Locking down a boom brake is a proven way to break a boom or snap lines and it is not recommended by the manufacturers (yes, I have discussed this face-to-face with the Waller brake designer).

What about a boom brake you only connect in conditions where you would consider a preventer?

Yup, some extra strings, but I would give it serious consideration for singlehanded passage making, since it is simple to use, no going on deck. Recovery is automatic.

==========================
very interested on how will you rig it.
if I can improve on what I have?

currently installed this
DUTCHMAN BOOM BRAKE / PREVENTER BB500B

https://www.landfallnavigation.com/d...xoC_l8QAvD_BwE

It is one of the things that truly worries me
an uncontrolled gybe

[GreenWave]

First, thanks for sharing an interesting experience. It has given me some things to think about.


In terms of feedback, most of this has been said. First, come off Autopilot in that much wind DDW. Second, I wouldn't even be Wing on Wing with 20 knots. Having a plan for how you will release the preventer or use it to change your sail positioning is something to consider (and like I said you have me thinking through more options).

[wholybee]

The best thing (preventor vs. brake vs. both) is highly depending on the geometry of the boat. Trying each is the only way to know what will work on a specific boat. There is no answer that is the best solution here.

On my boat, and I suspect on most boats with fore and aft shrouds (as opposed to them all being in line) with the preventer from the bow, outside the shrouds, to the end of the boom, I can _easily_ ease the preventor to centerline, and even past it by about 20 degrees.

With inline shrouds, or an exceptionally long boom, or both, that won't be possible on all boats. But on my boat, recovery is very easy. On boats that it isn't possible to ease the boom to centerline, you should be able to get withing 10-15 degrees of centerline, and with the traveler to leeward the mainsheet can take over, so still an easy recovery. Worst case, if the boom is uncontrolled through 10-15 degrees until the mainsheet catches it, that should be safe and reasonably controlled.

If your boat is such that none of that works then a boom brake is an option. I at one time had one on my boat. But it really sucked. The geometry was wrong, that was the real killer. And the tension on the brake is critical and needs constantly adjusted for windspeed. To tight, and it is a preventer, to loose and it doesn't slow the boom. If you adjust it for 15 kts of wind, then a squall hits you with 30 and you jibe, it isn't going to help much. And it requires two winches, while a preventor only requires one. Running both requires three.

Some people love the brakes though. If the geometry works, and if you have the winches to spare, you could learn how to work the tension.

[fidkid]

if you were on a gaff-rigged vessel I would say ease your peak halyard to take the power out of your main if you really wanted out of it fast (which I would)then let your head sails bring you back around and reset the main but I haven't done much with gaffless mains.

[Kd9truck]

Lots of good advice, yes to the backed main solutions, yes to the Auto pilot DDW.

on a vessel I crewed the owner had done over 20k DDW with preventers, the Genoa poled out and auto pilot. He said that over 8 knots with wind and sea directly astern the auto can not react quick enough, so to not be prone (like you were) we zigzagged DDW jibing with watch changes) with a wind angle between 170°-180° instead of 190°.
With his Oyster 56 and with my Jeanneau 44i more than 8 knots of speed the auto pilot starts to fishtail so the adjustment of 10°-15° you may be the solution to your autopilot failure.

Cheers

[Bill_Giles]

I don’t think that there is blame to be apportioned to the helm - human or auto. A veering or backing gust or an awkward wave can easily instigate an unwanted gybe. Your preventer did exactly what was required of it. Every boat is different and needs a different preventer. None of us probably experiment enough on our own boat especially in strong winds.

One does wonder though why one would go dead down wind in strong winds. A little off the rhum line costs little and may gain one speed anyway.

Abseilers (rappelers?) use a figure-8 as a brake, I have one and should experiment with it to slowly ease the backed main under control.

[lifeofreilly57]

A boom brake could help in that situation, releasing the preventer would allow a controlled gybe with the brake.
I'm looking to add one to my main after ripping out the toerail our preventer was attached to during a pop up squall at 3am heading for St Martin, going down wind. It went from 14 knots to 45 knots and swung 180 degrees in about 45 seconds. A boom brake would have slowed the gybe to a controllable speed. Fortunately neither the boom or mast fittings were damaged, but it could have ended badly. Getting a replacement toerail for an older boat was mildly expensive but fortunately I was able to source it. Prior to that I surveyed every beached and sunk boat in the caribbean trying to find that toerail, with no luck, I just had to pony up and buy new.
I also installed reinforced hard points to the deck to clip the preventer, with backing plates of course.

[Montanan]

Would recommend not attaching the preventer to a toe rail, instead attach it to the forward bow cleat which is much more robust than any toe rail and provides for maximum compression angle to apply the force against the end of the boom.


If the preventer is properly tensioned there will not be any force applied to a boom brake, albeit brakes do aid in slowing and easing the KABOOMing

[thinwater]

Originally Posted by wholybee

...And it requires two winches, while a preventor only requires one. Running both requires three....

In fact, I think they actually suggest a 3:1 tackle to prevent over tensioning with a winch (too powerful). I know this is the case with Waller, after talking with the designer at-length).


I too had one and didn't care for it. Easier to use the sheet and traveller then to futz with the tension just to get a so-so jibe. They intrigue me more as a heavy air safety for singlehanders (prevent damamge by slowing the boom some, if you blow it).

[Don C L]

Good to keep in mind also the gooseneck will take a lot of stress sideways and may not be up for it, and will need to be checked after a bad gybe.

[CarinaPDX]

I would reconsider going wing and wing in those conditions, but I am a cruiser with my racing days well behind. W&W is fundamentally unstable: increases in wind strength will usually increase weather helm. The problem is that the main's CE (center of effort) is pushing the boat from roughly the middle (fore/aft) but well outboard of the CLR (center of lateral resistance) so increases in wind and CE increase the yawing moment. The jib's CE is at the bow, well ahead of the CLR, and so has less yawing effect with wind increases. In 20+ knot winds and reasonably long legs I would have taken the main down, which would likely have had only a small effect on boat speed (cruising, not racing) but would have had a dramatic effect on steering stability and a great reduction in burden on the autopilot, not to mention the increase in safety from avoiding accidental jibes. As opposed to improving things with jib-only, the way many sailors make the situation even worse is to sail downwind with main alone - a horribly unstable way to power a sailboat. I have been aboard boats running with a main when hit with a gust, which rounded up with a vengeance in spite of heroic efforts at the helm. I believe this is often the result of avoiding the effort of bringing the main down, relative to the little effort required to furl the jib - a decision made for the wrong reasons.

Greg

[markxengineerin]

even worse is to sail downwind with main alone - a horribly unstable way to power a sailboat.

I am guilty of this, for a few reasons. Firstly, coming from dinghy sailing, I'm just more familiar with a main sail than a genoa, and when things get rough, I default to what I know. I also like the additional control that comes from having a rigid boom and all the associated controls for it. A main only is easier to furl/douse than a jib only, even with roller furler, it's a real challenge to roll up an out-of-control jib. Being single handed, I don't want to deal with a whisker pole, which is more difficult to set and control and more likely to kill me than the boom. I don't find any issues with rounding up with a reefed main, probably depends on the boat, but rounding up isn't as disastrous as an accidental gybe. Interesting discussions though, and I might change my mind if I had more experience w/ jibs/staysails. I do go staysail only if it gets above 35 knots. No poles involved.

[CarinaPDX]

It isn't any better of an approach on a dinghy, just easier to deal with - and if main only will kill your performance (N.B. for racers esp.). And going downwind simply does not require those extra controls, and especially with a strong wind. When out on the ocean and the weather kicks up rounding up can get pretty ugly, and is best done intentionally and early by getting the main down first. Furling the jib is easier in heavy going and usually does not require rounding up - but there is quite a range in performance of roller furling mechanisms. Having a backwinded main held with a preventer turning the boat abeam to the seas is downright scary in any real seas (the OP's situation but without the seas). A properly set whisker pole is not a problem to handle single-handed - I did it a lot on my own (a spinnaker pole is a bit more to handle). As always it is best to reduce sail early, before things get overpowered. And in deteriorating conditions switching from jib to staysail means furling the jib early, and the staysail is a whole lot easier to furl if needed.

Greg

[markxengineerin]

How do you furl your jib in heavy weather, with no main up to blanket it? I have done this ok with the staysail (head up a little to reduce pressure, then furl w/ winch before the flapping gets too out of hand) but can't imagine doing similar with the much larger genoa and in the conditions of a surprise squall. The above is not a quick process. Contrast this to heading up (likely to have already happened by itself in these situations) and simply dropping the main halyard, much faster, lazy jacks to catch the mess no matter how it comes down. The additional controls I'm referring to are the preventers, the traveller, lazy jacks, the halyard. None available or practical with the jib. Some will say "not available and also not necessary", but I don't know, I like having options and haven't had the "main only, sail downwind" strategy fail me yet in winds of 20 30 knots, doing hull speed or greater, seemingly in good control. Natural and strong weather helm seems like a good thing when a squall pops up.