DIY Boom Brake

[Dutch01527]

I have a 26 foot trailer sailer and have had a couple of minor accidental gybes this year when inexperienced crew were helming.

I liked the idea of a boom brake but they seemed to be very expensive for reasonably simple items. I bought a climbing abseil figure of eight device and fixed it with a shackle onto the boom at the vang hanger. I then ran a line from the toe rail just forward of the mast, through the figure of eight, down to a block on the opposite toe rail and back to a spare deck mounted jamming cleat by the cockpit.

It works perfectly. Gybes now cause a slow, controlled boom movement with no need to sheet in and/or slow the boom by hand. I can vary the tension to suit wind conditions by hand or using the cockpit winch. Total cost was under £10 ( I already had the block and line).

Obviously my boat is light weight and the loads are low but I think that it would scale up to something a bit bigger reasonably well.

 

[[70521]]

I prefer a simple preventer.

 

[{151760}]

I prefer a simple preventer.

A preventer's fine, but you have to unrig it, then re-rig it the other side. It does nothing to help control the actual gybe. I like the idea of a boom-brake, but I've been put off by the expense. I wonder if an abseiling thingy would be adequate on a 34-footer? Anyone know how strong they are?

 

[GHA]

I prefer a simple preventer.

You're allowed both if you want.

 

[oldvarnish]

Having enjoyed a boom brake for a few years, I now consider it part of the safety equipment (and not to be confused with a preventer which does a different job)

 

[Dutch01527]

A preventer's fine, but you have to unrig it, then re-rig it the other side. It does nothing to help control the actual gybe. I like the idea of a boom-brake, but I've been put off by the expense. I wonder if an abseiling thingy would be adequate on a 34-footer? Anyone know how strong they are?

I am pretty sure that the figure of eight would be strong enough for a 34 footer but I am not sure if there would be enough friction for the desired level of damping. However given that it only costs a few quid I would certainly give it a try if I had a bigger boat.

 

[savageseadog]

I am pretty sure that the figure of eight would be strong enough for a 34 footer but I am not sure if there would be enough friction for the desired level of damping. However given that it only costs a few quid I would certainly give it a try if I had a bigger boat.

Figure of eight's are extremely strong, would do a 40 footer

 

[zoidberg]

The alloy 'Figure Of Eight' or 'Descendeur' was designed for abseiling - as 'friction devices' - and there are several variants available. Set up as the OP has described, they are economic and efficient in the 'boom brake' role.

Mountain rescue and coastguard rescue teams have used them for decades, to lower not just one individual down/up a cliff, but a stretcher with two guides. They're plenty strong enough.

The degree of friction can be varied A) by the pre-tension in the rigged line; B) by altering the route followed by the line through and around the 'Fo8'; C) by reeving a doubled line.

 

[Champagne Murphy]

We have used one of these for some time now on a 32 footer.
It was nessessaryto double the line through it so as to get enough friction though.

 

[Spuddy]

How do you get on with the lines crossing the side decks? Trip hazard, just a nuisance or no problem?

 

[Dutch01527]

How do you get on with the lines crossing the side decks? Trip hazard, just a nuisance or no problem?

I use snap shackles to connect it up. Generally I leave it rigged when out for a day with loose lines when not sailing downwind and have not had an issue with it getting in the way. I guess it is a potential trip hazard but no more so than all the other lines running back to the cockpit.

 

[{151760}]

Thanks for the info. It's definitely worth a try.

 

[rotrax]

Figure of eight's are extremely strong, would do a 40 footer

Quite correct-I made one up for our Island Packet 350, 37 feet and a heavy boat with a fair size rig. It worked perfectly once tensioned. For extra friction two turns can be made around the figure of eight-I used a Petzl-which gave First Mate peace of mind when she was on watch running downwind.

The Petzl was cheap, I had a suitable line in stock, plus a couple of blocks which I spliced to short strops with heavy caribeners on the ends for quick attatchment to our centre cleats which were in a perfect position and a reliable strong point.

Good kit to have available IMHO.

 

[DJE]

I use snap shackles to connect it up. Generally I leave it rigged when out for a day with loose lines when not sailing downwind and have not had an issue with it getting in the way. I guess it is a potential trip hazard but no more so than all the other lines running back to the cockpit.

My boat came with a Scott Boom Brake and I took it off because of the problems caused by the lines across the side decks. Something of a trip hazard when walking forward but much more of a problem when clipped on to the jackstay. You either have to crawl under the boom brake line or unclip to get past it. I haven't missed it so far and this is with a 33 sq.m. mainsail on a 39 footer.

 

[martinaskey]

Likewise, have used this system for several years on my 36ft S&S (9 tonnes). It slows everything down and gives you the choice of allowing the gybe to continue without having to release anything or to get back on course. I'm a climber and I have absolutely no concerns about breaking the figure 8 device - The breaking load for this sort of device will typically be in the 20 to 30 KN range more than enough to not fail before pulling out deck fittings etc.. The devices are sometimes specified with a load limit for use as a rappel device but this is more to do with the amount of braking friction you can develop rather than mechanical failure of the metal.
Martin

 

[Dutch01527]

My boat came with a Scott Boom Brake and I took it off because of the problems caused by the lines across the side decks. Something of a trip hazard when walking forward but much more of a problem when clipped on to the jackstay. You either have to crawl under the boom brake line or unclip to get past it. I haven't missed it so far and this is with a 33 sq.m. mainsail on a 39 footer.

The degree of trip hazard might be linked to the width of the boat, mine is only 8foot 6 inch wide and the angles mean that the line is therefore pretty low. I guess that it is a balance of hazard. A trip hazard if access forward of the mast is required when sailing downwind vs accidental gybe / boom swing.

I often sail with my wife and/or friends who are novices (but learning quickly). I am normally the only person going forward on deck in anything but the most gentle of weather and on balance think that it is a safer option for them to be protected from boom swings.

 

[DJE]

The degree of trip hazard might be linked to the width of the boat, mine is only 8foot 6 inch wide and the angles mean that the line is therefore pretty low. I guess that it is a balance of hazard. A trip hazard if access forward of the mast is required when sailing downwind vs accidental gybe / boom swing.

I often sail with my wife and/or friends who are novices (but learning quickly). I am normally the only person going forward on deck in anything but the most gentle of weather and on balance think that it is a safer option for them to be protected from boom swings.

There is always more than one way to skin a cat. We tend to avoid sailing dead downwind and point up enough to keep the genoa full, we gybe from broad reach to broad reach using the mainsheet and traveller to control the main. Occaisionally we sail goosewinged but usually with a preventer on the main.

 

[oldvarnish]

I then ran a line from the toe rail just forward of the mast, through the figure of eight, down to a block on the opposite toe rail and back to a spare deck mounted jamming cleat by the cockpit.

I've been looking for an image of how you lace the figure of eight thingy. Any climbers can point me in the right direction?

 

[steve yates]

I've been looking for an image of how you lace the figure of eight thingy. Any climbers can point me in the right direction?

try this https://goo.gl/images/qoKM6a

 

[steve yates]

by the way, if you want greater friction, just reverse the figure of eight device.