Edited by bacho on Nov 24, 2015 - 07:22 AM.
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Greenville SC
Offering sails and other go fast parts for A-class catamarans
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The latest in trampoline tech!
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Posted: Nov 24, 2015 - 07:18 AM
This is a tramp that my shop was commissioned to build for a Foiling A-class cat. Sealed on the bottom, The tramp offers aerodynamic advantages. Being built from sail-cloth, its also extremely stiff making the center sheeting systems less "spongy". Its intended to be coupled with a deck sweeping main sail which would create an end-plate effect for the sail as well. New tramps available for Exploder A-class boats.
Edited by bacho on Nov 24, 2015 - 07:22 AM.
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Greenville SC
Offering sails and other go fast parts for A-class catamarans
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Posted: Nov 24, 2015 - 07:32 PM
That's cool! Is it slippery? What are the aero advantages? No air passes through the tramp?
Back to the debate about solid vinyl vs mesh Hobie tramps.
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Damon Linkous
1992 Hobie 18
Memphis, TN
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Posted: Nov 24, 2015 - 09:27 PM
Has nothing to do with the debate about solid or mesh Hobie tramps. Has to do with the end plate effect of bringing the mainsail down all the way to the tramp. This was proven at recent A cat worlds in Italy when Misha Heemskerk & Glen Ashby were well ahead of the pack because of mainsail down on the deck. Windsurfers found this out years ago with slalom sails designed to be raked back onto board deck. Pete -
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Posted: Nov 24, 2015 - 10:19 PM
The new sailed tramp
And the new boomless deck sweeper sail
but not on the same boat. Interesting.
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Jack B
Hobie 17
BC, Canada
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Posted: Nov 25, 2015 - 06:49 AM
Misha Heemskerk & Glen Ashby boat where not boomless but the boom was offset to one side of the sail to let it go down to the tramp.
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AB
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Posted: Nov 25, 2015 - 06:55 AM
The tramp is not reported to be any more slick than the mesh. It was even commented that shoes seemed to grip better on the sail cloth.
We brought down a prototype deck sweeping sail, however we were unable to try it as we had fitment issues with the boom. Turns out getting the boom allow full mast rotation and not hit the diamonds was harder than it looked.
We are going to try a boomless main again next as the builder for the booms will not be able to try again for a while.
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Greenville SC
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Posted: Nov 25, 2015 - 09:40 AM
how do you switch sides during a tack/gybe with the deck sweeping sail? -
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Posted: Nov 25, 2015 - 03:04 PM
You go behind it. As low as A-Cat books are already the space filled by the deck sweeper is pretty much no mans land anyway. -
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Posted: Nov 30, 2015 - 05:43 PM
Perhaps the additional sail area down to the deck has more benefit than the end plate effect. A pure right angle end plate is fairly draggy, due to junction drag. A convex or A-frame deck could ameliorate some of that drag. Tailored porosity in a standard tramp geometry might actually help. Has any of this been quantified with CFD or in a wind tunnel? It would be cool to see the trade offs.
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Posted: Dec 06, 2015 - 09:06 AM
My prototype sail matched with the tramp, really added to foiling stability.
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Greenville SC
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Posted: Dec 07, 2015 - 02:19 AM
Nice! Who is that? It's amazing what the A Class is doing with foiling. I'd that boat sailing to the International A Class rules or using the North American "exception".
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Damon Linkous
1992 Hobie 18
Memphis, TN
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Posted: Dec 07, 2015 - 08:42 PM
That is Bailey White, The boat is a fully class legal exploder A15.
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Greenville SC
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Posted: Nov 27, 2017 - 02:29 AM
Has anyone played with lowering the boom with a conventional main to get the deck sweeper effect? It would make crossing over more difficult, but if the gooseneck fitting went 50% lower, I wonder how much performance would be gained? Our Tornado is a fun boat so class legal isn't a comcern.
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Nacra 5.0
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Posted: Nov 27, 2017 - 02:50 AM
I talked to Randy Smyth about tramps once and he said on a non deck sweeping main setup, eg. theres no end plate effect to be gained, that a solid tramp would just create more drag and be slower than open netting. So if you have an old style cat the name of the game is getting the most breathable material you can use. But not open netting with holes so big your mainsheet would fall through.
I've thought about doing a park avenue boom to end plate the bottom of the main but I'm not sure if the added drag would outweigh the benefits. I might do some testing and see what happens.
The boom on my square mounts all the way down at the beam, but at the angle you need to still get under the boom at the back it still leaves a huge area for air to leak around and create vortices. Unless the sail is essentially completely sealed the effect is minimal from just moving the sail lower. You really need to add some material so you get the front half of the sail touching the deck.
I wouldn't just lower the main/boom down the mast solely to get it closer to the tramp because you're moving the sail into slower air all the time. Because the A class has to give up some area in the upper area of the sail to move it down low, the A's that run a DS setup are generally slower in light air. And from what I've read on the A forums I believe it's still up in the air if the reason they are faster in heavy air is due to end plate effect or just the fact that they have a lower center of effort and can carry more power due to more sail area down low.
Edited by tamumpower1 on Nov 27, 2017 - 04:07 AM. -
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Posted: Nov 27, 2017 - 12:48 PM
The word on the street is that DS sails are slower in the light air, but the race results over the past 6 months say otherwise...
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Posted: Nov 27, 2017 - 01:13 PM
Always hard to judge a new development when only rock-stars are using it. Sailors like Mischa can win races with anything, so anything they use looks fast.
It's the same game that sailmakers have played since the beginning of sailboat racing. Put your brand sails on a boat with the hottest sailors and your sails look really fast. Nobody ever gives their sails to the back of the fleet to demonstrate how much the slow guys improve.
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Damon Linkous
1992 Hobie 18
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Posted: Nov 27, 2017 - 01:28 PM
We were lucky enough to purchase the "used" gear from the Olympic Tornado sailors here for a few years (via jill/robbie of Red Gear Racing). It was amazing to get high quality sails, cutting edge tech (just slightly used, but no longer "new" enough for top level racers to use).
I had the Ogletree - Lovell main (had to cut off just a little for my 5,5 mast) and our friend had the Silver winning sail from the games in Greece on his 6.0. It was cuben fiber and he was fast! I currently have a "prototype" reaching spin from the last Olympics that had Tornado's still)
I like what they did with the alter cup (with all same cat models and gear) : where the teams swap (loaner) boats between races to keep things as fair as possible
Edited by MN3 on Nov 27, 2017 - 01:30 PM. -
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Posted: Dec 01, 2017 - 06:25 PM
Well to be fair, at this point there is many more people than just the rockstars using these set-ups. From my seat, the guys in the back are not any further back than they were before.
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Greenville SC
Offering sails and other go fast parts for A-class catamarans
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Posted: Dec 01, 2017 - 10:09 PM
The operative word there is “did.” Alter Cup has been a BYOB event now for several years. Not a very good indicator of the state of the sport when boat manufacturers can’t even commit to building 10 or 12 boats to support a national event because they’re afraid they won’t be able to sell them afterwards. Maybe they should hold the Alter Cup on Hobie TI’s....
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Posted: Dec 02, 2017 - 06:45 AM
As far as tramp stuff goes, as this was originally a post about trampoline technology, I would assume that if you are a racer you will want a mesh type of tramp. I'm old school, not a racer, so I would choose the solid vinyl because it's more of a dry ride and good for the sailing that I do. Anyway, in other news, with all the liability and competitive market these day, I can see why boat builders don't build specific race class boats for events like they used too. You're vehicle doesn't do well, then that's a sales killer, just like in the automotive world, race on Sunday, sell on Monday. The sailing community is very small compared to other sports so, manufacturers are cautious about putting a product out there that may not be up to standard. The boat loses, sales drop. Sucks, that a great boat may be fantastic but is skippered by a bad crew and looks bad. Hobie used to provide boats for national events, do they not still do that? I know the world of sailing is changing but damn, it's still a matter of a sleek hull, a sail, some wind and a way to make it all work. Happy sailing!!!
Edited by martyr on Dec 02, 2017 - 06:48 AM.
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Marty
1984 Hobie 16 Redline Yellow Nationals, "Yellow Fever"
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