34th America's Cup: multihulls!

34th AC Oracle flies

This is more like it-click-expand-click: Pictures here: http://oracle-team-usa.americascup.com/photos/748/17-Launch-and-First-Sail
Picture by Guilain Grenier:

 

oceancruiser - the rule intent is to prevent the use of negative lift on the daggerboard foil. If the daggerboard where designed to produce suction (which by design they can at present) then this would effectively increase the righting moment (Rm) of the boat. Since sailing is about maximising Rm at every second of a race this is a very good strategy. The rule creators however and others have identified that if we allow this strategy it could be very dangerous since we could easily double the boats Rm with foils. If a foil broke (and one has already) then the entire sailing team would be catapulted half way across San Fran Bay as if the AC72 had been turned into a large trebuchet. This rule does not apply to the rudder and we shall see the boats sailed very flat with both rudders in the water. The windward rudder will be used to trim the boat (up and down) so in effect the boats will be able to increase their Rm by using the windward rudder. This maybe why 17 has such a large rear beam to allow it to be stiff for this torque transfer. Once rules are set its the designers job to get around them!! Cheers Peter S

 

Doug -The pod underneath is this the "Black thing"? If it is your comment re "extending the wing downward to this" can't be correct. The profile of the wing is set by the rules and cannot be changed while sailing? The pod is that low because they are maximising the structural depth of it. They have built a monocoque boat vs using the spider web of prestressed cables underneath. The only tensile structure is to hold up the spinnaker pole. The spider web contributes a very large parasitic drag plus it creates a hugh internal stress in the structure that serves no purpose other than to stop the cables going into compression and then the structure could buckle. The white structures could come up to the wing however and this may need an interpretation to be legal. But the wing will be very efficient and saving the end losses is not really the problem in this case. The wing is hugely overpowered for the job. The real winning strategy is minimising drag to improve the lift/drag ratio hence pointing ability and terminal speed potential. Peter

 

Oceancruiser- I've just reread the rules and rudders can only have one direction of movment so twisting the platform will be the only way to use the rudder for trim. The original draft rules allowed two degrees of motion. Its been over 1.5 years since I've read the entire rules sorry about that, I see a few things have changed. Cheers Peter S

 

34th AC Oracle flys!

Here is a video of Oracle flying with the windward rudder out. I don't think she'll do that in racing-I think she'll fly with the boat level: ( flying toward the end)
http://www.youtube.com/watch?feature=player_embedded&v=84xmwDnfsoU

 

34th AC on Foils!

from the front page of SA: read the whole article and check the thread here: http://www.sailinganarchy.com/index_page1.php

Dean Barker shares his thought on the strange latest AC manuvering in the AC

Today the Event organisers dropped a bombshell on the Americas Cup competitors when they announced they will no longer be requiring the Teams to be based on Piers 30 and 32, and more importantly would not be paying for any redevelopment of the Piers as has been promised for the last 18 months.

I am sitting here completely stunned. We are a little over 6 months from relocating our base to San Fran to what we have been told would be a fully functioning base area complete with Team hospitality spaces and full access for the public to watch the teams preparing and launching their boats. It is now going to be a concrete slab with absolutely nothing on it which will now require us to secure cranes, jettys, and all services required to function. We have never budgeted for this and to be dropped on us now is quite unbelievable.

I have to say we are a long long way from the vision presented to us back in September 2010. Larry Ellison has done a lot for this AC and has put a lot of his own financial resource into making the Americas Cup next year a big event. However I think in terms of a lot of decisions made along the way by different people here we are with only 3 challengers and now no base facility to operate out of. This is a long way from the success of 2007 in Valencia no matter how you package it.

The catamarans are great but the AC72's are just way too expensive. Not only is the design and build of the new boats extreme, but then you need a small army just to launch and retrieve the boat each day let alone the work to maintain it.

 

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Peter, all I know about the Black Thing is what my friend said below and what Steve Clark has supposedly said(same thing but I can't find the quote).
He was right about the White Thing and both he and I have been right abut manual control and I think you and I are right about the windward rudder. I think Oracles system for the windward rudder may be better than TNZ since Oracle apparently has the ability to precisely control twist. Note in the picture below twist is almost gone and the windward rudder is in the water. The other picture shows the White Thing deployed to form an endplate.
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Pictures by Guilain Grenier for Oracle. Left picture shows The White thing forming an endplate with the fron section of the mast sealed against it, Right picture shows foiling with the windward rudder in and almost no platform twist-the first picture of 17 NOT twisted:
Cick and expand and click again for best view---

 

The leeward hull has an ugly oscillation when the cat is near flying, (towards end of video) bow up, stern still down, a strange and quite fast moving flutter ... that looked decidedly unhealthy. I could well imagine a similar situation breaking things, or straining hull/beam connections. Just an observation. Something I'm aware of from my own boat failings. Don't see anything like that on NZilla.

 

34th AC on Foils!

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I have a theory: since 17 is being flown manually if the "pilot" slipped or somebody bumped into him that could happen? The altitude didn't look so high that the foil was having effects from the wave, do you think?

 

Looked ugly to me, Doug - and it was not from some manual operating crew slipping on his urine, looked too fast, and more like a typically slack hull/beam connection being activated by an out of control foil. If not that, then it is an insufficiently stiff platform. Also if it continues during a race leg, the foil will be SLOW. Imagine it fluttering the same as the bow hull sections were in the video, will be distorted and dragging. Might as well hand the cup over now ... to the Kiwi wool shed mob camped on shore (which is the apparent alternative with the latest news).

 

34th AC on Foils!

I assume AC 45 World Series fron San Fran racing will be broadcast on u-tube here: http://www.youtube.com/americascup starting tomorrow(Wens.)

 

34th AC on Foils !

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Go back and watch the video again and watch the tiller movements -there is a series of quick ,hard moves by Spithill that are exactly in sync with the bow "flutter". rohanoz found it on SA.
heres a link to the video to make it easy:
http://www.youtube.com/watch?v=84xmwDnfsoU&feature=player_embedded

 

Thanks.

 

Pete,

What do you think about the suggestion that the induced drag on the rudder winglets as a consequence would be counter any benefit of suggested trim.


:?:

 

Who are you referring to. Team ETNZ or supporters as per your quote.

However who says the boats when it comes to 2013 will be foilers. Have you considered the track might not be suitable for foilers to win a race.

Heres the latest comments from your favorite man Hutchinson

Friday Oct 5, 2012


Both teams have demonstrated an ability to foil, but it remains to be seen whether it will be viable while racing the tight course in San Francisco Bay.

Hutchinson said " his team would certainly look at foiling as an option, but they were aware of the risks and rewards".

"You would be naive not to look at it and think hard about it. What you have to look at in the bigger picture is what goes around the race course the fastest".

"The trick will be whether you have the space or the room to allow the foiling to work for you."

Pete what do you think about this:


An evolution from the successful Prada campaign of the 2000 America's Cup, Patrizio Bertelli's Luna Rossa entered into a ground-breaking partnership with Team New Zealand late last year to ensure they could make the startline in 2013.

The Italians bought the design of Team New Zealand's first boat and, at the end of the testing period, both teams will go away and build their second AC72 independently.

They plan to launch the boat in Auckland on October 26 and will do all their testing in New Zealand, although there are strict rules around information and data sharing between the two teams under the America's Cup protocol.


Team ETNZ consider their biggest threat to winning the cup is Luna Rossa not ORACLE.

It's a evolution not a revolution maybe