Preventer v Boombrake

[Arcarius]

What are the pro's & con's of a preventer v a boombrake for downwind sailing ? apart from price of course .I am thinking of the ARC in a couple of years .I cannot find any information in the magazines on these products.
Thanks in advance Garyc

 

[Sans Bateau]

Firstly welcome to the forum

This year I fitted a Walder boom brake. It makes gybing easier and safer, it is always rigged, it can also be used to tame the boom in light airs when the wash from another passing boat might knock the boat about a bit. The Winchard version is much cheaper and my rigger gave it a good review (after I bought the Walder!)

 

[Blue5]

Preventer gets my vote

We use a continuous line from boom end to a block at the bow, back down windward side to rear winch and from there back to boom end, it means you do not need to leave the cockpit and you can control the gybe.

It works for us on a 40ft boat and the only cost was a new block for the bow

 

[Norman_E]

I have a Scott boomlock, always there and normally in the "unlocked" position, but locked when running to prevent a gybe. Very useful to stop the boom swinging about due to wave action or wash in light winds. In an intentional gybe the friction can be controlled to allow the boom to move gently across.

 

[tudorsailor]

What material for your preventer

I have a preventer rigged with a line from each side of the boom. These clip onto a long sheet that comes inboard at the bow and then back to a turning block and onto a winch.
While coming back across Biscay the preventer was set by the PYD skipper. He used the winch to get it really tight, and then sighted along the boom to see if it was overly tight and not bending the boom!
While running dead downwind (at night) we had an accidental gybe while on autopilot. Fortunately the guy on the helm turned off the autopilot instantly to stop us gybing back again. No real harm done other than a couple of bent stanchions. The gybe was relatively damped

How did this happen with the preventer set? The answer is that there is enough stretch in the lines that add up to almost twice the yacht's length to allow the boom to cross the midline.

For me the question now is whether to buy dyneema lines for the preventer!

TS

 

[tcm]

The answer is No, not dyneema for preventer, nor any such inelastic line all designed to hold up a sail in an exact position... as it will potentially shock-load the boom. If at all possible, praps use more elastic lines such as a three-strand nylon, or special-purpose elastic braided lines. Same applies to mooring lines of course and is the reason why some boats jerk about...

 

[jerrytug]

Tudorsailor that's interesting do you think ot would not have gybed if the preventer had been made off at the bow ie half the length?
I don't know about dyneema but I would always make a preventer of the thickest rope on board which is long enough,and you can let the boom out a bit too far,make the preventer off at the bows then harden the mainsheet to pretension the preventer,saves a double length stretchy preventer.
B brakes can knacker your gooseneck andwill be fighting your topping lift I hate them personally cheers Jerry

 

[jimi]

I have a preventer rigged with a line from each side of the boom. These clip onto a long sheet that comes inboard at the bow and then back to a turning block and onto a winch.
While coming back across Biscay the preventer was set by the PYD skipper. He used the winch to get it really tight, and then sighted along the boom to see if it was overly tight and not bending the boom!
While running dead downwind (at night) we had an accidental gybe while on autopilot. Fortunately the guy on the helm turned off the autopilot instantly to stop us gybing back again. No real harm done other than a couple of bent stanchions. The gybe was relatively damped

How did this happen with the preventer set? The answer is that there is enough stretch in the lines that add up to almost twice the yacht's length to allow the boom to cross the midline.

For me the question now is whether to buy dyneema lines for the preventer!

TS

Static (or semi static) ropes like pre stretchetched polyester sheets are about 5% stretch see http://www.riggingandsails.com/pdf/marlow-info.pdf

Now on a 35 boat with a 10 ft boom out at 80 degrees , you will need the rope to stretch another 6 feet to get past the mid point, based on overall inital length 0f 56 feet (35 sheet winch to bow cleat) + 21 feet (bow cleat to boom end) ie 10% stretch. Now considering that some of the stretch has been talready taken out by tensioning the preventer, then if the boom is capable of passing the mid point then the rope used in unsuitable for this use. Perhaps a stretchy mooring warp had been used by mistake? As far as shock loading goes, my take is that if the boom is set hard and unable to move then it will not be shock loaded as in my mind shock loading is caused by rapid stop of movement... no movement = no shock loading. I stand to be corrected if my understanding is incorrect.

 

[Conachair]

Never used a boom brake but have preventers prememently rigged attached roughly about level with the mast coming back to a cleat by the cockpit. One of the most used cheap add ons. Line is 8mm climbing dyneema, just a touch more give than the SK75 stuff, mainly because I had some. Works very well in light airs, between the preventer, sheet and topping lift you can lock off the boom whereever you want and get down to a good book for a week or so

 

[webcraft]

As far as shock loading goes, my take is that if the boom is set hard and unable to move then it will not be shock loaded as in my mind shock loading is caused by rapid stop of movement... no movement = no shock loading. I stand to be corrected if my understanding is incorrect.

Agree - non-stretchy rope well tensioned, no boom movement, no shock loading.

The boom arrangement on Mojomo is a weird affair, so TCM is not really talking about the same apples IMO.

- W

 

[Enya]

We use a continuous line from boom end to a block at the bow, back down windward side to rear winch and from there back to boom end, it means you do not need to leave the cockpit and you can control the gybe.

It works for us on a 40ft boat and the only cost was a new block for the bow

Hi NDH

I was interested in your set up. I have a 27 ft boat and have twice been caught by the mainsheet (when not helming) and thrown onto the side of the boat with painful results. I am wondering where your "continuous line is fixed and where it runs free. I do not have a winch at the back, just ones for the genoa. Obviously I need to keep out of the way of the mainsheet but failing that.
Is there much risk of loss of control in say force 4/5? Enya

 

[samwise]

We have been very satisfied with our Wichard Gybe Easy boom brake which is a very simple but very effective system, the downside is that it is also very expensive for what appears to be just a metal moulding and a length of special rope.
However, for our kind of sailing it justifies its claims and has removed the worry of a sudden and possibly destructive unexpected gybe.

It will not perform the ultimate preventer task of holding the boom in place against a seriously backwinded main. For that you would need to rig a more traditional system via a block on the bow and round to the boom end. However, in our experience it has held the boom in most conditions and if an unexpected gybe does occur it happens at a gentlemanly pace and under control.
The Wichard device is rigged at a point where the kicker attaches to the boom and the special high friction rope is run down to turning blocks on the side deck and back to the cockpit. The device offers three different settings with three friction levels that can be adjusted quickly and simply by moving the rope loop in the fitting.

I have to say I had misgivings when I first took the thing out of the box, because it seemed a lot of dosh for not much. However, two seasons later, I would not be without it.

 

[[2574]]

The Wichard device is rigged at a point where the kicker attaches to the boom and the special high friction rope is run down to turning blocks on the side deck and back to the cockpit.

How do you terminate the lines back in the cockpit? Do they need to be on a winch? Or will a cam cleat do? How much tension is necessary on the line, can you pull it on by hand?

Rob

 

[samwise]

How do you terminate the lines back in the cockpit? Do they need to be on a winch? Or will a cam cleat do? How much tension is necessary on the line, can you pull it on by hand?

Rob

We usually bring it back to a winch, but a jammer would do. It can be easily pulled in by hand

 

[Enya]

Given the price of the Wichard Boom Brake which seems to be a very good product, I am tempted to make up something from a climbers fig of 8. I would not expect such all round performance as the Wichard but could experiment.

 

[lw395]

I think people need to be clear what they want from preventers and boom brakes.
If you want to seriously prevent the boom from crossing the boat when running in seas and weather, then a preventer rigged between the clew end of the boom and the bow is a sure way to do it. In these conditions, anything that attaches in the middle of the boom stands a good chance of breaking the boom if you roll the clew into the water at speed.

If you want to stop the boom flapping about in light weather and sloppy sea conditions, something attached to the kicker is very helpful.

In terms of damping the boom as it crosses the boat in a controlled gybe, that is what the mainsheet is for! If it's very hard to control the main using the sheet, maybe investing in better blocks or a more powerful purchase would make your sailing more pleasant?
A ratchet block that helps ease in a controlled way is worth having IMHO.
Or maybe you should have reefed?
A decent kicker system helps too.

 

[oldvarnish]

In terms of damping the boom as it crosses the boat in a controlled gybe, that is what the mainsheet is for!

On a smallish main, I agree. But with a big sail on a multi-part purchase sent to a winch then hauling in and letting out can be a slow business. With a big and fit crew, no problem - except for the accidental gybe.
For those of us who seem to be lightly crewed most of the time I still think a boom brake is a first class device.
Pity they're so expensive.

(Walder is my choice)

 

[Graham_Wright]

Given the price of the Wichard Boom Brake which seems to be a very good product, I am tempted to make up something from a climbers fig of 8. I would not expect such all round performance as the Wichard but could experiment.

……………or an Anka which is like a figure of eight but has horns to prevent the rope capsizing. We use one for single handed MastaClimba ascents (or rather descents!) where a capsize is "interesting".

 

[tudorsailor]

Tudorsailor that's interesting do you think ot would not have gybed if the preventer had been made off at the bow ie half the length?
I don't know about dyneema but I would always make a preventer of the thickest rope on board which is long enough,and you can let the boom out a bit too far,make the preventer off at the bows then harden the mainsheet to pretension the preventer,saves a double length stretchy preventer.
B brakes can knacker your gooseneck andwill be fighting your topping lift I hate them personally cheers Jerry

In the incident that I described, the preventer was set up by the PYD skipper who is vastly more experienced than me. I guess the advantage of leading the preventer back to a winch is the ability to adjust tension from the cockpit. However I would agree that a line led a cleat at the bow would have less stretch potential.

In future I will not sail almost dead downwind on autopilot in windvane mode. I think I will make off at the bow rather than the hassle of leading back to a winch.

TudorSailor