Using an abseiling 8 as a boombrake

[Ric]

I would like a boombrake as I s/h long-distance and have had a couple of nasty accidental gybes.

I've looked at several boombrakes on the market. The best one seems to be the Walder, which is a nicely designed bit of kit, lets the boom slide across nicely, and can be controlled from a single-line lead aft.

But whilst canyoning last weekend, it occured to me that it would be a lot cheaper to just use an abseiling 8. Has anybody tried this? I expect there would be a bit less control, but just a guess.

Sorry if this is the second time i have asked this - I asked a few days ago but don't know where my post went cos it never appeared on the site..

<hr width=100% size=1>

 

[Stevie_T]

You could possibly use a Petzl Stop, it is used in abseiling (which is my job).
It does the same thing as a figure 8 only it doesn't twist the rope and has a lever which controls the friction and the speed of descent giving full control and is easy to lock off. There are other devices used in industrial abseiling which also might do the job.

<hr width=100% size=1>

 

[Talbot]

I just use a length of rope from end of boom to fwd cleat - cheap and does the job.

<hr width=100% size=1>

 

[john_morris_uk]

Safer if your bit of rope from boom end to forward cleat goes round cleat and back to cleat in the cockpit. (Saves having to rush to the foredeck to let go the line if you need to sheet the main in for some emergency or w.h.y....)

<hr width=100% size=1>

 

[Ric]

Yes but wait until a big wave hits you, dunks the end of the boom in the drink and either rips out your mainsail or snaps the boom in two...



<hr width=100% size=1>

 

[castaway]

Ric lets hear a bit more about this bit of kit... I use the same method as Talbot but wouldnt recomend it..

Can one buy on the web?? Is the material fairly marine proof?.

Regds Nick.

<hr width=100% size=1>

 

[Stevie_T]

Depends what you mean by marine proof, they are all made of aluminium, so will corrode somewhat, but even so I would have thought they would last for years.

It must be understood that I am not necessarily promoting the idea, in fact I had never thought of it, but the idea seems in principle a good one and suggested the Stop as what I think will be better than the figure 8.
The stop has full control of friction, and defaults to the stopped position unlike the figure 8 which will run through at full speed unless locked off or controlled by hand.
Whether it would be any better than a rope from the back of the boom to a forward cleat and back to a cockpit winch I dont know but could possibly be easier to deploy and may use up less rope.

They can also be used as part of an effective hauling system in conjunction with a couple of pulleys.

Here are a couple of links to the manufacturers site one for the stop and a possible alternative the Grigri
http://www.petzl.com/petzl/SportProduits?MotRecherche=Quick+Search&Langue=en&Activite=0&Famille=9&SousFamille=74&News=

If you would like any more details about them, I will not be around for a couple of weeks but it would be interesting to try one out (I have several )


<hr width=100% size=1>

 

[claymore]

Too complicated and not that necessary
the thing would be bound to jam or the 8 create too much friction. I had a scott boomlock which I eventually gave to Jimi as it was such a pain. Go with the rope preventer fastened well forward and keep it simple

<hr width=100% size=1><font color=purple>regards
Claymore<font color=purple>
/forums/images/icons/smile.gif

 

[Gunfleet]

Don\'t sail on dead runs? nm

<hr width=100% size=1>

 

[john_morris_uk]

Re: Don\'t sail on dead runs? nm

If you are in big enough seas (and presumably winds) to worry about the boom hitting the water and breaking one hopes that you have thought of the possibility and taken steps.

Perhaps you would have made sure that the gybe preventer was to the end of the boom? (I know some peope rig the preventer to a point mid way. A boat I was in for a leg of a RTW race had lost its boom on an earlier leg for just this reason.)

Perhaps you might reef the main which usually races the boom?

Perhaps you might think of sailing downwind under one or two headsails only?

Take the point about not sailing dead down wind, but sometimes you can be in danger of gybing on a broad reach if the seas are making you yaw all over the place. Night time on long passages, helms do get it wrong more often that we'd like to admit, and autopilots are often worse as they can't anticipate the yawing action.

<hr width=100% size=1>

 

[Talbot]

If the big wave hits my boom, I will have more problems than worrying about the mere fact that the mast and boom have snapped! My boat is a cat, and the boom is 7ft above the cockpit, which itself is another metre above the water, furthermore it has a loose footed sail. /forums/images/icons/smile.gif

<hr width=100% size=1>

 

[Roberto]

I usually do not like to use any kind of boom brake or preventer, except in particular circumstances (eg novice crew, heavy seas), but I happened to be in a friend's boat where he had installed exactly that 8-system, and it worked a wonder, by tightening the rope the boom swings more or less quickly, it was surprisingly smooth

result I bought one of those 8, they are 5-6 euro if I remember...



<hr width=100% size=1>

 

[MainlySteam]

Being a non descending type here could you or someone describe how the figure 8 descender is rigged to serve as a boom brake. And are they robust enough to control mainsails on say 40 ft plus boats? Sounds interesting.

Thanks

John

<hr width=100% size=1>

 

[Roberto]

Hi John,

the one I have seen was like this: one of the two circles of the eight was connected around the boom by a bit of webbing (for a loose footed mainsail, but any other kind of fitting could do), then a rope is fixed to one side of the bulwark rail (hope it's the right word), goes through the other ring of the 8, then ends to one side of a a tackle whose other extremity is fitted to the bulwark rail symmetrically to the dead end of the rope; the tackle rope then goes to the cockpit

e.g. port side rail --> boom --> starboard side tackle

on the Petzl site there is a description of a few possible different paths of the rope through the ring of the eight, yielding different levels of braking

by carefully choosing the fore and aft position of the rope and tackle along the rail, and by adjusting the tension on the tackle (max tension-->boom is blocked) it is possible to trim the speed of boom movement

a rope diameter of 10 (best) or max 12 is usually ok, a 14 would cause too much friction imho

hope it's understandable...

rob


<hr width=100% size=1>

 

[MainlySteam]

Many thanks for that Roberto.

I see from the Petzl documentation now how the rope goes through the 8. Would be easy to set up on our boat using a block on the toerail and back to a winch at the cockpit for the adjusting end. So I will have a look at one and see if it looks strong enough and if so I think that I will give it a try next season (is winter here now). If not strong enough for a bigger mainsail it would possibly be easy to have something similar fabricated from ss.

John

<hr width=100% size=1>

 

[Ric]

Thanks for the links to the more sophisticated pretzl descenders. Having used those for abseiling, I don't think they would work well for a boombrake as they only descend in one direction. Also, they are light alloy wheels on ss spindles and so would need a lot of care and rinsing to make them last beyond a few months in marine environment. The advantage of the 8 is that rope slides around it in both directions. The other big advantage is that it is simple and robust and would last in a marine environment.

<hr width=100% size=1>