Boom Brake

[charliehows]

Originally Posted by brownr377

Following - I've got a wickard brake that came with the boat. I rigged it up once and had trouble getting the tuning right, it was either too loose and didn't put any brakes on or it was too stiff and didn't let the boom gybe.

I'm quite certain it was operator error, any tips are appreciated.

The type and size of rope is what you need to look at - i started off using 10mm 16 braid - way too fat, went down to 6mm, still not much good, then tried 6mm dyneema - perfect because its so slippery. Remember, if set up right, the brake is never under much pressure - it's job is to slow down the booms travel, stopping it from building up power in its arc. In stiff winds, with the brake on a hard setting, there will always be some stiffness in getting the boom to start but this is just a matter of developing a procedure - I usually haul in the mainsheet to get it to kick over, or nip up and give it a shove if it wont go.

[thinwater]

Originally Posted by a64pilot

I wonder why they had a winch on both ends of the line?
it would seem that logically you can attach one end to the mid ship cleat and the other around the other clear and then to a winch, it would seem that loosing either side does the same thing, slackens the line?
The line doesn’t run through the brake of course, it’s the tension of the line that provides the friction for the brake to slide over the line.

I'm not sayin' you need to winch both ends, but...


The line stretches during the jibe. This is required, and high-mod line won't work, but if you winch on one-side-only, the amount of stretch on each tack is different and the degree to which it slows the boom will be different.


There are brakes that tension from the middle.


I've never found one that actually offered smooth jibes, but they can serve as releasable preventers, that allow the boom to move across after you've goofed. I see the benefit for short-handed sailing, but I've tested several and am not a fan. Most of the time it's just "one more thing."

[a64pilot]

Of course it’s one more thing, but I need something and have a brake.
I don’t see how it’s any more hassle than a preventer.
Costs more money, but it came with the boat, so that isn’t an issue.
I just ordered enough line to set it up correctly, although getting it to the Bahamas is not going to be cheap, fast or easy.

[a64pilot]

Originally Posted by thinwater

I'm not sayin' you need to winch both ends, but...


The line stretches during the jibe. This is required, and high-mod line won't work, but if you winch on one-side-only, the amount of stretch on each tack is different and the degree to which it slows the boom will be different.

Line should have very little stretch, and the tension on both sides of the brake has to be the same, whether both ends are on winches or one is attached to the mid ships cleat.

[a64pilot]

I just watched the video again and I think I understand why two winches.
That way you can ease tension on the side that has less tension on the line and that should be easier to control since there is less tension once the gybe has occurred.

[a64pilot]

Originally Posted by boom23

You could use a strong wide strap, which you can have stitched at a sail shop.
It does not have to be permanently mounted on the boom.
Just an idea...

I just found this site, which sells slings pre-made and with more than one ply: Lifting Slings

I would have the block closer to the bow though.

Unfortunately since I have an in boom furling system, you can’t put anything around the boom. You pretty much have to go with the track that is in the bottom of the boom.

[thinwater]

Originally Posted by a64pilot

Line should have very little stretch, and the tension on both sides of the brake has to be the same, whether both ends are on winches or one is attached to the mid ships cleat.

Low stretch, yes. Nylon would be a disaster. But not zero stretch, since the length of the line, through the range of motion is variable.



I think whether you find the tension variation from one tack to the other important depends on the unit and how it is used. I noticed and many people have reported this... including some of the manufacturers, as I recall.


If you use it as a releasable preventer, as many do, then it makes no functional difference. IMO, it is when folks think of it as a tool for every jibe that they get into trouble. It is going to be smoother to control the jibe with the mainsheet (pull in, let out), rather than turn until the wind gets behind the mainsail.

[daletournier]

I have a Dutchman, haven't thought much of it until last week.

It's not easy to adjust or at least not easy to get the adjustment right in my opinion, I don't use it to gybe, I release the lines and control the boom with the mainsheet as I would without it, the adjustment is just to hard for me to get right. I see it as a trip hazard.

In saying the above, I screwed up the other day. New crew, I was concentrating on them and not what I was doing. Rising following sea, rising wind 30-35k (eventually 40-52) and I accidentally gybed. The boom still come over hard but was slowed considerably and nothing broke.

I believe without the Dutchman I may of had a breakage.

I now have a new found respect for it.

[BigBeakie]

It might be instructive to some to read the NZ Maritime Safety report on the deaths of 2 cruisers aboard PLATINO due to the failure of a preventer rigged to amidships, instead of to the bow where it should be turned and lead back to a winch aft or in cockpit.

The analysis in that report shows that the forces on all parts of the midships preventer system are 25 times greater than if rigged to the bow in an accidental gybe.

Who in their right mind ,given that analysis , would still rig to amidships?

Also, a boom brake is not a preventer.

Search Maritime New Zealand accident report Platino


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[cj88]

Some think that if they have always got away with it then why change to something proven to be safer. This attitude relates to lots of things. Personally I don’t have an issue with that approach unless it has the potential to put others at risk. Risk your own life, not others.

[Matt Johnson]

Originally Posted by BigBeakie

The analysis in that report shows that the forces on all parts of the midships preventer system are 25 times greater than if rigged to the bow in an accidental gybe.

Who in their right mind ,given that analysis , would still rig to amidships?

Also, a boom brake is not a preventer.

You said it right there.... the boom brake is not a preventer and it being mounted midship isn't the same issue. Unlike a rigid preventer, the brake acts as a fuse and releases the pressure of an accidental jibe without breaking the rig. They work great for small mainsails like the OP is asking about.

We have a Walder brake and rig when needed. Port side of the line terminates with a snap shackle that gets clipped on the toe rail. Starboard side is a single block with a snap shackle that goes to the other toe rail. The line then leads through the block and back to the cockpit.... we use a 4:1 tackle to tension the line, but a winch works too. All gets unclipped when in port to make going forward easy.

Matt

[Jim Cate]

Originally Posted by cj88

Some think that if they have always got away with it then why change to something proven to be safer. This attitude relates to lots of things. Personally I don’t have an issue with that approach unless it has the potential to put others at risk. Risk your own life, not others.

Well, not going to sea is surely safer than doing so. I've gotten away with it for a long time... should I quit? Sailing downwind with only a head sail is safer than with a mainsail with no boom to worry about. Should I strike the main every time I turn downwind?

Risk management is a big part of sailing, and learning from experience what works helps with that management. Extrapolating from specific failures is not always the best tool in risk management IMO... useful info, perhaps, but not the only things to consider. If loads are higher, then engineering for those loads is a good idea, and apparently can produce good results for some folks.

I guess I'll just go on using my well tested system.

Jim

[BigBeakie]

How would you suggest engineering for loads 25 times greater than normally experienced? Have padeyes 25 times greater SWL? Same with lines? and blocks? And snap shackes?

I wouldn't expect you to strike the main to deal with downwind sailing in a seamanlike manner, but given that this is perhaps the first time these loads have been well quantified, and shown that rigging a preventer to the end of the boom is a MUCH safer and thus better seamanship option, why not adopt it? Whats the downside?

Saying that nothing bad has happened to me yet is.....perhaps accurate. Nothing has happened.....yet. Not exactly the same as saying it can't or won't happen, is it?


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[BigBeakie]

Meant to say from the end of the boom to the bow.


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[Jim Cate]

why not adopt it? Whats the downside?

Well, our system is permanently rigged. Setting the preventer/vang is simply tailing a line and placing it in the jaws of the self tailer. To invoke its power as a superb vang, a turn or two on the winch handle hauls the boom down with less stress on the mast and goose neck than a conventional vang (which we also have but seldom use).

The angles that are involved with the lines are not as extreme as those shown in your diagrams, and the long term survival of the gear, living through uncountable gybes, is well demonstrated. When we wish to make a planned gybe, we turn down until the sail fills gently on the other side and then, using the winch as a snubber, ease the boom across and then set the opposite preventer, all from the helm.

This system works, and because it is so simple to use, it is always set when the wind is aft of the beam... all from the helm and without much effort. The downside that you ignore is the loss of this proven system to effect a change to one unproven and untested, and that does not provide the easily controlled gybe that we now enjoy. Also, when one needs to stabilize the boom, say at anchor, setting both preventers keeps it firmly in place. When coupled with a rigid conventional vang like ours, it largely replaces the function of a boom gallows.

One downside that we endure: the added friction of the preventer tackle means that the boom is slow and heavy to move in light airs... this can be a nuisance.

Jim