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Old 22-05-2013, 16:32   #1
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Boom Brake vs Preventer

I've never been comfortable using tethers on the boom and since ive fitted a boom brake i dont even think of them as an option - what are the arguments in favour of preventers vs boom brakes? I admit that my antipathy to preventers has meant i have never bothered rigging a tether that could be used without having to go forward - more to do with the complications of my oddly designed boats than anything else - so may be a bit biased, but since fitting the boom brake - the one i use works like an abseiling device so no controls required - gybing is easy and , even when unplanned, safe.
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Old 22-05-2013, 16:48   #2
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Re: Boom Brake vs Preventer

Boom brakes are kind of like an automatic transmission but ugly. If you have a rigged preventer all the time it's pretty easy to use.
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Old 22-05-2013, 16:56   #3
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Re: Boom Brake vs Preventer

Preventers: Pro

1) Save wear and tear on gooseneck by preventing the boom from oscillating
2) Save wear on the mainsail batten pockets (particularly if rigged as a toe-rail vang) by stopping the main from "panting" against the lee rigging
3) Twin preventers (toe rail type) can stabilise the boom at any angle: to prevent cracks on the head from a slatting boom when close hauled; to make it safe to put in a slab in a sloppy seaway (a gallows substitute), et alia
4) Allows using the main as an accurate 'air rudder': useful for tricky manoeuvres such as weighing anchor under sail in close quarters, heaving to under main only, coping with a steering failure etc....
5) Less expensive than a brake
6) With ingenuity, the toe-rail preventer/vang can be 'fused' in a progressive way, so that the boom is protected from overloads, but the crews' heads are also kept from harm.

Boombrakes: Pro

1) Operationally easy (and hence free from operator error), usually at least semiautomatic, sometimes fully: this is particularly beneficial for a solo sailor doing demanding trips, or someone who sails with lots of untrained crew.

(Declaration of partiality: I used to prefer boombrakes and end-boom preventers, but have moved solidly into the twin, permanently rigged toerail preventer/vang camp, as of about fifteen years ago... however with a skinny boom I would feel queasy about any mid-boom solution, whether vang or brake. On a dedicated racing boat, particularly with a long boom (eg big fractional main without a commensurately wide beam) I would stick with end-boom preventers, I think)
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Old 22-05-2013, 18:01   #4
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Re: Boom Brake vs Preventer

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Originally Posted by Andrew Troup View Post
...with a skinny boom I would feel queasy about any mid-boom solution, whether vang or brake. On a dedicated racing boat, particularly with a long boom (eg big fractional main without a commensurately wide beam) I would stick with end-boom preventers, I think)
I feel the same way. My boat has end-boom sheeting, and I think it unwise to rig a boom brake because that would have to be mounted mid-boom. If I had a boat with mid-boom sheeting I might actually consider a boom brake just because of how much easier it would be to jibe.
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Old 22-05-2013, 21:38   #5
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Re: Boom Brake vs Preventer

hmmm, figures - i have a mid boom sheet, rigged the boombrake on the same fitting, easy
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Old 22-05-2013, 21:45   #6
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Re: Boom Brake vs Preventer

I rig preventers because they're really simple and work. For long downwind runs where I'm not doing any sail adjustments, I'll run the preventer all the way to the sampson posts to keep the boom really solid. Gybing isn't all that difficult, you're easing one preventer as you sheet in, easing the main sheet back out again, then tightening up the new preventer.

Pretty simple. You can use two old halyards for your preventers.
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Old 22-05-2013, 22:01   #7
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Re: Boom Brake vs Preventer

After a couple of accidental gibes, I mounted a pad eye on each side of the main boom's aft end. When we have significant down wind runs to make, I run a line from the pad eyes on the boom to a block that's attached to the base of the bow pulpit. The line then runs back to the cockpit (through a turning block and up to a rope clutch). By having the preventer run all the way to the bow, we have a lot of control over the main boom. Gibes, even in heavy weather, are a piece of cake and accidental gibes are a thing of the past.

Fair winds and calm seas.
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Old 22-05-2013, 22:12   #8
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Re: Boom Brake vs Preventer

I should perhaps have clarified: if you go for end-boom preventer to the bow, you really need a boom brake as well, for safely gybing a big rig in strong winds on your own.

The angles get too acute too quickly with a bow preventer for it to safely control the boom through the first phase of the gybe, and of course you have to switch to the main to control the second half.

Whereas with a vang-preventer, it can also be used (and should be used, IMO) to control the entire gybe. The manoeuvre is carried out quite differently with a v-p or brake vs with the mainsheet only: you don't normally bring the boom in to prepare for the gybe, unless some other considerations (like setting up the new runner, or extreme conditions of wind or sea) dictate.

So you steer around far enough for the main to flop across while the boom stays put, and at that moment but not before, ease the vang preventer 'handsomely', surging it around a spare winch in the correct direction (ie as if it was a sheet you had tightened using the winch handle) to absorb the energy. You are only dealing with static forces, not kinetic energy, which makes a considerable difference.

Don't be standing or sitting on it, and don't have a loop around the pedestal or engine control lever! The advantage is that
(unless you've overdone the number of parts in the tackle: I've found by trial and error that two's enough up to a big-rigged 40' sloop)
you don't have much line to worry about.

If it's endless (as I mentioned in another thread which is running at present), so much the better... no stopper knots to get themselves caught in narrow crevices...

Provided your procedures are robust and careful, and the gear is strong and well thought out and installed, I would argue a heavy air gybe with a v-p is safer than the traditional "centre the boom" method on big and/or heavy boats, particularly if they're a bit slow to respond to the helm in big quartering seas (which includes many if not most 'traditional bluewater' boats).

That's because centering the boom before you gybe means having to manage steering the boat within an increasingly small angular window while cranking in hundreds of feet of mainsheet, which you have no opportunity to flake before having to let it out with a rush the moment the sail gybes - a moment which is sometimes difficult to predict.

And throughout the time you're bringing in the main, the boatspeed drops and the apparent wind builds, the opposite of what you want. If you're solo, you'll have a bit on.
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Old 01-06-2013, 09:43   #9
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Re: Boom Brake vs Preventer

Looking at a 1968 Cal 36 with the Boom Brake below. The seller claims the Boom Brake acts as a Vang as well. I don't understand how. When the boom is sheeted out, wouldn't the angle on the brake lines be too wide to hold the boom down?
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Old 06-06-2013, 20:51   #10
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Re: Boom Brake vs Preventer

After an VERY sudden wind change one day while running downwind, I installed mid-boom preventers, one each side. A line goes from the coming on the side of the cockpit, through a Spinlock PX cleat (easy to set, easy to undo just using the rope) up to a block attached to the main shroud's substantial eye on the deck, then up to a block on a boomvang ( this block is attached to the vang by a snap shackle for easy removal if necessary) then back and truncated at the main shroud eye block.

As a solo sailor, this has proved very useful, and possibly saved my life a couple of times.
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Old 06-06-2013, 23:57   #11
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Re: Boom Brake vs Preventer

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Originally Posted by L124C View Post
Looking at a 1968 Cal 36 with the Boom Brake below. The seller claims the Boom Brake acts as a Vang as well. I don't understand how. When the boom is sheeted out, wouldn't the angle on the brake lines be too wide to hold the boom down?
The vang lines are attached to the bottom of the boom-brake vs the boom itself.

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Old 07-06-2013, 01:20   #12
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Re: Boom Brake vs Preventer

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The vang lines are attached to the bottom of the boom-brake vs the boom itself.
Ok. So you still need a vang.
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Old 07-06-2013, 05:08   #13
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Re: Boom Brake vs Preventer

I made a boom brake because they are often written about on forums... But it never worked well for me. So I ditched it and use preventers. They both are long bits of line from the mainsheet attachment at the boom, then out to the admidships mooring cleat, then back aft to the aft mooring cleats

The attachment at the boom is a roving of light line with an aprox 400 kg breaking load.


Works well.
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Old 07-06-2013, 06:00   #14
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Re: Boom Brake vs Preventer

I use a preventer. I installed a line on the boom attached to the end runs to the other end and has a loop it, this line is always on the boom. Then I have another line that I run from the cockpit to the forward cleat and back to the boom line and secure it in a winch that I can adjust the tension or release easy.
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Old 07-06-2013, 14:14   #15
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Re: Boom Brake vs Preventer

We use a Gyb'Easy (Wichard) boom brake. Attachment is mid-boom using a wide strop rather than a permanent padeye. May be just an illusion but seemed as if a strop would spread the load out a smidge and maybe provide a little bit of additional elasticity in shock loading.

There are two ways to adjust Gyb'Easy's braking effect. The first adjustment is how its line is passed through the abseiling device (on our boat, position one works up to about 15 knots; position two up to about 20; and three for anything more. The second adjustment is the tension applied to the braking line. If I throw it around a winch and pull it in firmly by hand, we get graceful, even stately, controlled gybes. If I crank it in hard -- bar tight -- it becomes almost as immovable as a preventer. Best of both worlds.
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