Preventer Rigging?

[SVNeko]

Thanks for asking all these questions. Its good to get others' thoughts on the issues you post about.

We use an icicle hitch 3/4 back on the boom with a loop on it. This gives a good angle for the preventer (too far aft and it compresses the gooseneck too much; too far forward and it presents a boom-breaking opportunity). Connected to the loop from the icicle hitch are two NYLON lines forward to a snatch block at the spring cleat, back to a block on the aft mooring cleats and into the cockpit (when those aft blocks are being used by the gennaker or spinnaker, we cleat the preventer off on the aft cleat). When not needed, the preventers are led forward and coiled and hung at the mast and the blocks rest on the deck. No gymnastics to set them.

[Phoenician]

Coincidentally, I just changed my furling line. I had indeed reached the same conclusion as you did: out went the 12 mm double braid, and in came a 10 mm dyneema. Plenty strong indeed, and lighter, but I have to admit, much less comfortable to handle than then 12 mm. To be honest, I'm not sure that I will stay with it. I will give it a try for a few months and determine if the 12 mm wasn't a better choice after all.


I don't use a preventer, but I'm overjoyed with the Walden 403C boom brake. It's made a huge difference when running with the wind, particularly with the kind of short swell we get here in the Eastern Med coupled with light winds. The boom brake smoothly absorbs any violent swing when tossed around by the capricious waves.

[Dockhead]

Originally Posted by Phoenician

Coincidentally, I just changed my furling line. I had indeed reached the same conclusion as you did: out went the 12 mm double braid, and in came a 10 mm dyneema. Plenty strong indeed, and lighter, but I have to admit, much less comfortable to handle than then 12 mm. To be honest, I'm not sure that I will stay with it. I will give it a try for a few months and determine if the 12 mm wasn't a better choice after all.


I don't use a preventer, but I'm overjoyed with the Walden 403C boom brake. It's made a huge difference when running with the wind, particularly with the kind of short swell we get here in the Eastern Med coupled with light winds. The boom brake smoothly absorbs any violent swing when tossed around by the capricious waves.

Why is the 10mm less comfortable? Do you haul it by hand? We never use it but with an electric winch.


No preventer?! I just can't get my mind around that. A boom preventer is as fundamental as a backstay. Or a mainsheet. To my mind. Don't you ever sail downwind? On my boat, the preventer goes on whenever the boom goes off beyond the end of the traveller. I can't imagine at all, not fixing it in place.

[Phoenician]

Clearly, comfort is a subjective notion :-)

I'm surprised - and interested to learn more - by your stance on boom preventers. Wouldn't a boom brake perform the same function? I have found the boom brake to be a perfect solution for downwind sailing, particularly on long downwind passages that we typically have when returning from Cyprus or Turkey. Also, it seems like overkill to use both a brake and a preventer, if that is even possible (unless I am missing something?)- Happy to be enlightened!

[Dockhead]

Originally Posted by Phoenician

Clearly, comfort is a subjective notion :-)

I'm surprised - and interested to learn more - by your stance on boom preventers. Wouldn't a boom brake perform the same function? I have found the boom brake to be a perfect solution for downwind sailing, particularly on long downwind passages that we typically have when returning from Cyprus or Turkey. Also, it seems like overkill to use both a brake and a preventer, if that is even possible (unless I am missing something?)- Happy to be enlightened!

I've never used a boom brake, so this might just be ignorance on my part.

Anyone else have an opinion?



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[transmitterdan]

Originally Posted by Dockhead

Why is the 10mm less comfortable? Do you haul it by hand? We never use it but with an electric winch.

If one has ever had a foresail halyard wrap whilst winching in the furling line then forever that person becomes an evangelist for not using a winch (electric or manual) for furling. A halyard wrap, while rare, will absolutely ruin your day/week/month. I admit to being lazy sometimes and taking in a bit of sail using a cockpit winch on the furling line but its not a good practice. If the upper swivel happens to carry the halyard around the stay even once then the entire foil will be destroyed and the sail may not come down without a trip up the mast.

Originally Posted by Dockhead

No preventer?! I just can't get my mind around that. A boom preventer is as fundamental as a backstay. Or a mainsheet. To my mind. Don't you ever sail downwind? On my boat, the preventer goes on whenever the boom goes off beyond the end of the traveller. I can't imagine at all, not fixing it in place.

I agree that preventers should be always rigged when wind is aft. Our preventers are permanently rigged. A pair of blocks at the boom (about 3/4 aft) and a becket block shackled to a massive pad eye near each toe rail and just aft of the mast gives enough purchase. The working end of each preventer line is led to the cockpit where there is a massive stopper. This arrangement acts as both a preventer and a boom vang. And it prevents having a long line run to the bow. But it requires detailed installation of the deck pad eyes due to the huge loads they may be called on to resist. This idea won't work if your deck does not have internal reinforcement (no coring under the pad eye) and huge backing plates below.

[transmitterdan]

Originally Posted by Dockhead

I've never used a boom brake, so this might just be ignorance on my part.

Anyone else have an opinion?



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A boom brake is better than nothing. A boom brake does not prevent an accidental jibe but it does slow it down considerably Hopefully it slows enough to prevent damage or injury to the crew. The energy absorbed by the brake is converted to heat in the line and the brake itself (it gets hot). This reduces the energy available to break "stuff". It is better than no preventer but isn't enough for some people. Some do not want the boom to carry across until they wish it to.

[SVNeko]

I didn't think there was a boom brake big enough for your boat.

[barnakiel]

It depends on the boat. When the boom is very long or/and very low, a preventer tied from mid boom to mid ship may break the boom.

Boats with other configs and strong boom profiles may go unscathed.

b.

[Dockhead]

Originally Posted by transmitterdan

If one has ever had a foresail halyard wrap whilst winching in the furling line then forever that person becomes an evangelist for not using a winch (electric or manual) for furling. A halyard wrap, while rare, will absolutely ruin your day/week/month. I admit to being lazy sometimes and taking in a bit of sail using a cockpit winch on the furling line but its not a good practice. If the upper swivel happens to carry the halyard around the stay even once then the entire foil will be destroyed and the sail may not come down without a trip up the mast.

If I had indeed ever had a halyard wrap, it wouldn't change the fact that I couldn't furl my 129m2 Yankee jib by hand if my life depended on it. I don't think two people could do it, either. Electric winch for me, please.

My next boat will not have furling lines at all; rather hydraulic or electric furlers. I guess you'd REALLY hate those. But they work - beautifully.

Originally Posted by transmitterdan

I agree that preventers should be always rigged when wind is aft. Our preventers are permanently rigged. A pair of blocks at the boom (about 3/4 aft) and a becket block shackled to a massive pad eye near each toe rail and just aft of the mast gives enough purchase. The working end of each preventer line is led to the cockpit where there is a massive stopper. This arrangement acts as both a preventer and a boom vang. And it prevents having a long line run to the bow. But it requires detailed installation of the deck pad eyes due to the huge loads they may be called on to resist. This idea won't work if your deck does not have internal reinforcement (no coring under the pad eye) and huge backing plates below.

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[Phoenician]

Walder makes an absolutely brilliant boom brake (I don't own any shares in the company). In fact, that's all they do, and I think they do it very well.

There are 6 models, the largest one designed for main sails up to 110m2. It is a very sturdy piece of equipment, and with all due respect to transmitterdan, it is much, much "better than nothing". The tension on it can be adjusted, - from fairly elastic, to serve as wild swing "absorber", to very tight, almost like a preventer.

Gamme - Walderweb


I also like the fact that you can keep it set at all times, and tack or gybe with it, just by releasing the tension on the brake.

[s/v Jedi]

Yes, a boombrake is good to absorb shockloading during gybes. However, it can not hold the rig steady in light weather with swell conditions so you still need preventers when sailing offshore in less than 15kt winds.

[transmitterdan]

Originally Posted by s/v Jedi

Yes, a boombrake is good to absorb shockloading during gybes. However, it can not hold the rig steady in light weather with swell conditions so you still need preventers when sailing offshore in less than 15kt winds.

There is wisdom in this post. We use our preventers sort of like a vang in light wind. It helps set the sail shape and prevents the boom jumping around a lot.

[Dockhead]

Originally Posted by transmitterdan

There is wisdom in this post. We use our preventers sort of like a vang in light wind. It helps set the sail shape and prevents the boom jumping around a lot.

I use the vang a lot downwind, so don't really need the preventer for that purpose, but I certainly want the boom fixed in place when going downwind.

Light wind is the obvious case -- to keep the boom from flopping around and spilling air out of the sail.

But even in stronger wind, the boom just shouldn't be out there free to flop around. It's just wrong (IMHO). What if there is an eddy of wind? Or the boat jinks around? I don't want that boom going anywhere than where I have set it, when it's hanging out over the side. Once it's off the end of the traveller, I balance the boom between mainsheet and preventer.

[geoleo]

Originally Posted by Dockhead

I have always rigged my preventer the old-fashioned way – take a length of 12mm rope, tie one end with a bowline through the end loop of the boom, lead that around a midship cleat, and back to a winch. Voila.

Then this summer I realized with horror that the angle is all wrong. It pulls mostly DOWN on the boom, which means a strong impulse back will snap the preventer. All these years I’ve been doing it wrong!
I have just installed strong padeyes on the rail forward, from where I think I should have a much better lead.

I am going to make up a low friction eye with a dyneema strop (which I learned to splice last year, hurrah) to use as a snatch block.
But it got me thinking that there must be a better way to rig the preventer. With a sea running, it’s a PITA to stand on your toes and tie that bowline through the boom end loop, and the other end of the preventer takes up a precious winch.

How do others do it? Maybe splice a loop through the boom end, and use a snap shackle at the end of the preventer? Or rig it premanently?
If the latter, how would you store it? I don’t fancy leaving a hank of rope hanging off the end of the boom at all times. I guess it could be led further up the boom and hung there. Or maybe just a snap shackle?
Any tips?

Another preventer question: It seems to me that your preventer doesn’t actually need to be as strong as all that – it’s purpose is to keep the boom from slewing around and generating snatch loads. If it’s held in place, it don’t produce enormous forces. So why not use a somewhat smaller, easier to handle line? I’m thinking of downsizing from 12mm to 10mm. Or maybe 10mm Dyneema for lightness and strength, hmmm? Maybe with the cover stripped off half of it?


And while we’re at it – let’s talk about furling lines. I use 12mm double braid, which is heavy and bulky and fills up the furling drum. Now why such big line for this? I have big Selden S400 Furlex furlers, but they don’t generate forces which would challenge 10mm double braid, I don’t think.
What do you guys use on your furlers? Maybe here again some 10mm cruising Dyneema with the cover half stripped off would be cool – very light and easy to handle, and much less bulky in the drum, and plenty strong enough. Hmm?

Overkill! Just take a 1/2 nylon dockline from end of boom to a convienient stanchion and tie a loop in it at a convient height then run the line from the stanchion thru the loop and tie a slip knot--- easy to undo and retie if you gybe. Wheww