All the boats on this page are rigged with ropes stretched between ends of the boom.
If it works for guys that a completely fatigued and sleep deprived to sail the boat safely around the world , it is more than safe for your average cruiser sailing anywhere they would likely find themselves. This is not some theoretical idea,ย it has been in play for many years on boats that cannot afford any failures in areas where rescue is out of the picture .
This is an open 50 with a huge mainsail and 23' boom ,you can see the vang line.
The following 4 images show Open 60 class boats. The wad of black hanging under the boom at midpoint is the thimble sliders.
Above: Vendee nonstop around the world boat.
Above: Gooseneck Attachment.
Above: Open 50 Artforms with Allen Neubauer 94 BOC skipper delivering from NZ the rock that is behind the downhaul line is "THE ROCK" or Cape Horn for the yachties
IMPORTANT UPDATE: Preventers are notorious for breaking booms so should not be installed like most people do. If its a preventer you use to prevent an accidental boom gybe on a monohull , you will want to fuse it with a small line that will pop if the boom was to drag in the water otherwise you will have catastrophic failure from the water load , on multis it's different, if you drag your boom, you are in bigger problems. Either system you may use will need to attach to the boom somehow, and most attach it directly causing all the failures you hear about because of the point loading. Here is what I have been doing for years and have never had any failures because of pure mechanics . I use a very stout high tech line, either spectra/dyneema, vectran or one of the other flavors and run it along the underside of the boom from front to back. This line needs to be pre stretched to take out any sag and it is lashed tight one end to the other. Anything like a brake or preventer line is attached to this line and can be free running back and forth along theย length as it will find its true center . The brake/preventer now puts the boom in pure compression load through the tensioned line, and unless the load generated is incredibly high the boom will never break. I use a preventer line when sailing downwind (Leopard 47) to vang sheet the main to get proper leech twist. I also never sail any deeper than 150 degrees apparent as this is useless on any boat especially on a multi where you will be going slower than the wind. It is better to gybe downwind and keep the speeds up a little, it is also safer in the fact you won't round down causing an accidental gybe. Hope this helps you understand the principle. - Troy Bethel (ex professional racer)
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