Preventer
We wanted end-of-boom preventers for the mainsail. Many boats opt for preventer/vang systems in which the block and tackle is attached on each side near the edge of the deck, providing both downward and forward forces to stabilize the boom. There are conditions under which the vang/preventer systems can lead to boom breakage. Since our boat already had a hydraulic boom vang we were predisposed to a separate preventer system. After the debacles with our standing rigging, traveller, and mast work we decided to ask Toss Rigging to come up with a preventer solution.
Brion Toss' preventer system consists of two pieces of line for each side. The first is slightly shorter than the boom and is attached to a padeye at the end of the boom. There is a section of bungee spliced inside the cover and the other end is an eyesplice. The bungee provides enough tension to slide the eye over a horn cleat near the goose neck for storage.
The boom out for a nice downwind run.
The second piece of line has a caribiner splice to one end. This line is long enough to reach the bow and run back to the cockpit.When we are at sea the forward line for each preventer is run from the aft deck cleat, through the forward hawse, then back to our gate where we clip the caribiner to the lifelines. When we need the preventers we grab the eye of the line attached to the boom off the cleat near the goose neck and attach it to the caribiner. We then let the mainsail out farther than necessary, tension the preventer, than pull the main sheet back in. This tensions the whole system, preventing any movement.
We are very happy with this system. In 20 foot seas off the coast of Washington the boom was rock steady.
In the next picture we are off the Baja coast running wing-on-wing with the jib poled out with the spinnaker pole. This has become our favorite downwind sail combination.
A very nifty preventer system, thanks to Brion Toss and his employees for executing it so well.