…Spain, site of the trials for the America’s Cup. These guys are crew on one of the boats & have come up with some nice looking designs:
http://www.youtube.com/watch?v=zdTwjnitVlk
http://www.youtube.com/watch?v=ZVhsyI7KwnU
The stretchy stays appear to be real stabilizers.
The stretchy stays appear to be real stabilizers.
Bill,
I’m not a landyacht sailor… is the flexible stay an inovation here, or has it been around in other machines? If not, this has to be VERY exciting!
Very cool videos, thanks.
yar
Yar,
Please see the attached photo of Tony Johnson’s new rig as an example of the alternative to the stretchy stays, as a means to stabilize the boat. If you notice, he has a long “springboard” extending from the front of his hull, as well as a bendy “plank” serving as the rear crossbeam/axle. These elements will allow the entire platform to flex downwards, which in turns allows the mast to tilt sideways. Tony states:
“What is very evident in a puff is the plank and springer compression with mast fall off. You can see the whole rig sort of pumping during acceleration.”
The composite wingmast allows lateral bend during gusts which serves to flatten sail camber & increase twist.
I still think this approach bears investigation for use in multihulls to decrease capsize potential.
Also, the new wingmast was one (of two) that Tony & I built 2 weekends ago for him & Harry Allen in Minneapolis, Minnesota. The picture is from Lake Minnetonka.
Bill
Hi William:
How is Tony’s mast stepped? I’m new to all of this, so forgive my ignorance. Is the mast mount flexible or is the mast flexible? Because the boat depresses, or sinks downward in wind gusts, does that loosen the stays and, thus, allow the mast to bend with the wind?
Thanks for your help,
Dave
Hi Dave,
Good questions.
The mast is mounted on a swivelling bolt on top of the boom, allowing it to rotate freely. The same bolt continues thru the boom & terminates in a “socket” (a drilled out #10 socket head cap screw) which is then stepped on a round head brass wood screw on the deck. This ball & socket joint allows free rotation in all directions. Thus, the mast & boom can both rotate independently of each other.
The mast itself is also flexible, allowing a limited amount of lateral bend in a gust which results in sail camber flattening, as well as simple energy absorbsion.
The platform flexure is a separate issue. It absorbs gust energy as well as allowing the side stays to slacken, which causes the rig to “slop” off to leeward & spill excessive air.
You may want to check out http://groups.yahoo.com/group/IRCSSA/
for more pictures & information.
Regards,
Bill
http://www.youtube.com/watch?v=7mOVKwPpL2Q
Bill:
Thanks for taking the time to explain.
Dave
Dave,
The closeup shot might help you see how it is set up
Taken the same day as the video, but from the other side of the rink . Wish the video had been from that side, to avoid the backlighting.
Bill
Thanks William. That helps a great deal. What an innovative (it sure seems so to me!), excellent setup.
Dave