A cheap boom brake

[Roberto]

An old idea I recently tested on my boat, in case anyone is looking for a cheap boom brake solution.

The basic element is a moutaineering "eight", cost about £10.
I have fitted a textile shackle on the smaller ring, this allows it to be attached to the boom in a convenient place. The kicker upper fitting may be a good starting point.

The controlling rope is attached on the bulwark at about the mast height, it goes through the bigger ring of the "eight", then to the opposite side of the bulwark where a block allows it to be directed to the cockpit.

By varying the tension on the rope it is very easy to trim the speed of the boom during a gybe.
A very taut rope literally blocks the boom in position, acting like a real preventer.
Too slack and obviously the whole thing becomes useless.
It takes a few tries to properly adjust it, a few cm can make a lot of difference.
Once the right tension is found, it can be left alone.

The rope on the picture is an old three strand one, after a few tries I'd say that a less "hairy" rope, more flexible and more slippery would be preferable, one could try with an old genoa sheet for example.

This is the brake in action.






http://sybrancaleone.blogspot.fr/2012/09/eng-simple-boom-brake.html

 

[rotrax]

An old idea I recently tested on my boat, in case anyone is looking for a cheap boom brake solution.

The basic element is a moutaineering "eight", cost about £10.
I have fitted a textile shackle on the smaller ring, this allows it to be attached to the boom in a convenient place. The kicker upper fitting may be a good starting point.

The controlling rope is attached on the bulwark at about the mast height, it goes through the bigger ring of the "eight", then to the opposite side of the bulwark where a block allows it to be directed to the cockpit.

By varying the tension on the rope it is very easy to trim the speed of the boom during a gybe.
A very taut rope literally blocks the boom in position, acting like a real preventer.
Too slack and obviously the whole thing becomes useless.
It takes a few tries to properly adjust it, a few cm can make a lot of difference.
Once the right tension is found, it can be left alone.

The rope on the picture is an old three strand one, after a few tries I'd say that a less "hairy" rope, more flexible and more slippery would be preferable, one could try with an old genoa sheet for example.

This is the brake in action.






http://sybrancaleone.blogspot.fr/2012/09/eng-simple-boom-brake.html

Got just about the same setup, but with a large snap shackle to clip to a dedicated extra bale I recently installed on the boom. Works great, just like yours, and was installed for the same reason- controlled gybeing. Doubles as a preventer too, when pulled really tight. I have two blocks on lanyards and snap shackles to raise the control line run to avoid it rubbing on the coachroof sides. I might blue the dosh on a clutch to improve it- its just on cleats at the moment.

 

[Salty John]

Very interesting to see that idea actually in operation.

Those rappelling rings are available widely at under £15 and it seems they do the job as efficiently as the Wychard Gybe'easy (I think it's called) at £250!

The danger with those plain rings is that if the line goes slack the loop can fall off the ring and lock around the incoming line. Any indication of this happening, Roberto? You can buy a version with short 'wings' that prevent this happening.

 

[lw395]

To be honest, that gybe looks less controlled than I would like to see.
What's it going to be like in twice as much wind?
Much better just to do it properly by sheeting the main in and controlling its run out using the ratchet block.
Boom brakes are good for stopping the boom rattling about in light winds and sloppy seas, and that's about it. Worth having just for that of course.
In heaver weather, running, you still need a proper preventer rigged to the clew end of the boom

 

[Blueboatman]

Clever.
Suggestion, mostly to myself to try....The same thing with one of the tails fed through a toerail snatch block and thence to a multi part block n tackle whose inbuilt jammer is within arms reach at the cockpit..would be a very finely tunable/ quickly releasable thing. Maybe

Thx for sharing and the clear photos

 

[Roberto]

To be honest, that gybe looks less controlled than I would like to see.

You can pull the line to completely stop the boom if you like, then it is a matter of adjusting the correct tension to get the speed you like.

Ideally, while the boom moves there should be no slack created on the two sections of the line.

Just writing as thoughts come: if I remember correctly from high school, the geometric figure created by "all points whose sum of the distances from two given focus points is a constant" is an ellypse (correct ? incorrect ?).

Then the length of the line being fixed, the two rope attachment points on the deck being fixed, the "eight" describes something similar to an ellypse (I think it is more a spatial shape, not lying on a single plane?).

If so, as the boom turns, on one side we have the boom attachment point describing a circle, which should be counteracted by an ellyptical movement.

It should be possible to arrange the attachment points so that the projection of the ellypse on a horizontal plane (the one the eight describes) becomes a circle: in this case the two sections of the rope should always have the same tension and the turn be perfectly controlled.
Big question marks as to this theory




Anyway, in practice we made just a few tries, at the beginning the attachment points were further aft from the mast and the boom slammed, then we shifted them at the same position as the shrouds and it was a lot lot better.
The rope I had had too much friction, another one with a smoother sheath would be better.




Salty John
You are right an "eight" with the two additional winglets would avoid that risk.
Mind you, with the rope under tension then I saw no loop falling over itself, if it is very slack then the boom turns irrespective of the position of the rope around the eight.
The problem might arise if the position of the various points (see above) causes the two sections of the rope to be unequally tensioned.
Another thing to try

 

[lw395]

...
Just writing as thoughts come: if I remember correctly from high school, the geometric figure created by "all points whose sum of the distances from two given focus points is a constant" is an ellypse (correct ? incorrect ?).

Then the length of the line being fixed, the two rope attachment points on the deck being fixed, the "eight" describes something similar to an ellypse (I think it is more a spatial shape, not lying on a single plane?).

If so, as the boom turns, on one side we have the boom attachment point describing a circle, which should be counteracted by an ellyptical movement.

It should be possible to arrange the attachment points so that the projection of the ellypse on a horizontal plane (the one the eight describes) becomes a circle: in this case the two sections of the rope should always have the same tension and the turn be perfectly controlled.
Big question marks as to this theory




Anyway, in practice we made just a few tries, at the beginning the attachment points were further aft from the mast and the boom slammed, then we shifted them at the same position as the shrouds and it was a lot lot better.
The rope I had had too much friction, another one with a smoother sheath would be better.




....

All this fine tuning is going to be different every time, depending on how wet the rope is for one thing.
Would it not be easier to use the mainsheet properly?

 

[Roberto]

Would it not be easier to use the mainsheet properly?

That is what I have done until now, not sure about "properly" but only used the mainsheet so far.

A few tests with setup might be interesting though, who knows

 

[DinghyMan]

Was having a look on ebay for prices for the figure of eight and spotted one with "wings" - http://www.ebay.co.uk/itm/ISC-ALUMI...ing&hash=item2ec12b598e&_uhb=1#ht_1404wt_1141,

 

[Blue5]

After a previous thread on the subject we tried exactly the same set up on our 40ft boat and I was not impressed, it certainly slowed the gybe but only marginally and I soon reverted back to our conventional preventer.

Dont get me wrong I am all for innovation and a cheaper solution and I have played around with various cordage configurations and a figure of eight but have not yet found one I am happy with.

 

[Roberto]

After a previous thread on the subject we tried exactly the same set up on our 40ft boat and I was not impressed, it certainly slowed the gybe but only marginally and I soon reverted back to our conventional preventer.

Dont get me wrong I am all for innovation and a cheaper solution and I have played around with various cordage configurations and a figure of eight but have not yet found one I am happy with.

thanks for your feedback

Two things I am not happy with so far:

a. in the setup I have tried, the two sections of the rope cut diagonally straight from boom height and down to the bulwark; I really do not like a rope at waist height in the middle of the boat, so I think I will experiment with other positions for the attachment points (possibly at the shroud bases) to have a more contained setup, which does not spread from side to side across the boat

b. I still have to try it with the genoa unfurled (we furled it while we were trying it first time as me made several dozen gybes): the two sheets might interfere with the rope, this can be an additional constraint on the position of the attachment points

regards
r

 

[Blue5]

Best of luck, my impression was that with the the fig of 8 you could not get enough resistance to slow the gybe, I tried adding rings and carabiners to get more resistance but it was becoming a monster!!

 

[john_morris_uk]

The tension is a function of boom height so I don't understand how you could set it accurately. On our boat you could never leave such a device set up 'accurately tensioned' as the boom angles don't allow it. (Tight enough on the run with the boom out would be slack as the boom comes inboard.

I also agree with you that having a line across the boat at waist height is a potential hazard.

I am all for innovation but I just can't see how this is ever going to be set up work effectively.

I wouldn't use it as a preventer - In heavy winds I prefer the preventer to go to the very end of the boom.

PS when we gybe, I overhaul the main to the centre line (or nearly) and just let the mainsheet go and allow the friction of the line in the blocks to control the main running out. One loose turn round the mainsheet winch as extra friction in very strong winds but its very rarely needed.

 

[William_H]

The tension is a function of boom height so I don't understand how you could set it accurately. On our boat you could never leave such a device set up 'accurately tensioned' as the boom angles don't allow it. (Tight enough on the run with the boom out would be slack as the boom comes inboard.

I also agree with you that having a line across the boat at waist height is a potential hazard.

I am all for innovation but I just can't see how this is ever going to be set up work effectively.

I wouldn't use it as a preventer - In heavy winds I prefer the preventer to go to the very end of the boom.

PS when we gybe, I overhaul the main to the centre line (or nearly) and just let the mainsheet go and allow the friction of the line in the blocks to control the main running out. One loose turn round the mainsheet winch as extra friction in very strong winds but its very rarely needed.

Hi John just on the lighter side and not at all helpful to the preventer problem.
I got involved with some "professional instructors" a while back. In fact checking out my instructing ability. Some of the paper work describing gybing used terms like rooster over the stern and smoking the main (sheet). I hadn't heard these terms and was made to look a bit of a fool for not knowing when I asked (as sailors do) Rooster over thes tern means the wind pointer ( and wind) dead astern. Smoking the mainsheet is exactly as you describe. ie pull the mainsheet in and dampen the gybe as the boom pulls the main sheet through all the pulleys. (apparently generating smoke if you do it right?)
good luck olewill

 

[maby]

After a previous thread on the subject we tried exactly the same set up on our 40ft boat and I was not impressed, it certainly slowed the gybe but only marginally and I soon reverted back to our conventional preventer.

Dont get me wrong I am all for innovation and a cheaper solution and I have played around with various cordage configurations and a figure of eight but have not yet found one I am happy with.

I did some research with a mountaineering acquaintance into this a few yeas ago and we came to the conclusion that the figures of eight that are readily available are only really enough for boats up to around 35 foot. They are designed to control a load of around the weight of an adult male which is probably less than the loading on the mainsheet of a forty footer in a moderate wind.

 

[john_morris_uk]

Hi John just on the lighter side and not at all helpful to the preventer problem.
I got involved with some "professional instructors" a while back. In fact checking out my instructing ability. Some of the paper work describing gybing used terms like rooster over the stern and smoking the main (sheet). I hadn't heard these terms and was made to look a bit of a fool for not knowing when I asked (as sailors do) Rooster over thes tern means the wind pointer ( and wind) dead astern. Smoking the mainsheet is exactly as you describe. ie pull the mainsheet in and dampen the gybe as the boom pulls the main sheet through all the pulleys. (apparently generating smoke if you do it right?)
good luck olewill

Hi Will, That's very interesting. One of my occasional anxieties is sailing with other very experienced sailors (the sort who make you feel inferior by their manner and custom!) who then go on to use language that I've never heard of. Although I have been sailing for years and I am the first to admit that I am still learning, when people start using words and terms and making you feel an idiot for having to ask what they are talking about then it really winds me up inside.

I would be seriously worried about actual smoke coming from the main - I assume they mean steam!

Rooster over the stern I have never heard of.

The challenge I often have with crews coming sailing with me on 'larger boats' is that the techniques that you can get away with on a 22 foot boat (or even a 30 foot boat) can't always be used on a 55 or 70 foot boat (or even our 39 foot, 12 tonnes of boat)

PS So called professional racing crews are the worst for their 'superior' airs and language. I hope you enjoyed your sailing.

 

[dgadee]

I did some research with a mountaineering acquaintance into this a few yeas ago and we came to the conclusion that the figures of eight that are readily available are only really enough for boats up to around 35 foot. They are designed to control a load of around the weight of an adult male which is probably less than the loading on the mainsheet of a forty footer in a moderate wind.

What about this:

http://www.northwashoutfitters.com/store/index.php?act=viewProd&productId=208

 

[maby]

What about this:

http://www.northwashoutfitters.com/store/index.php?act=viewProd&productId=208

Difficult to decide based on pictures alone - I don't think the limiting factor is the physical strength of the device - it's more a case of the amount of friction it can achieve against a rope.

 

[rotrax]

Difficult to decide based on pictures alone - I don't think the limiting factor is the physical strength of the device - it's more a case of the amount of friction it can achieve against a rope.

I purchased and use a Petz FoE. It is possible to use two turns around each side to increase friction. I have not needed to so far.