34th America's Cup: multihulls!

[Silver Raven]

Originally Posted by P Flados

I agree that altitude control is required.

With the crew available on this size boat, manual control would be possible.

Given that an aiplane pilot controls both steering and altitude, I would be tempted to assign altitude control to the man on the helm.

If manual altitude uses the rudder for control, the entire boat Angle of Attack (AoA) would be adjusted (just like a traditional airplane). Putting the extra complexity all on the rudder makes sense to me given what is allready going on with the dagger boards (one goes up & the other goes down on each tack).

FYI, as I recall, the paper on Rocker indicated that they felt that the poor performance was due to four foils in the water all of the time. The photos of the Oracle boat show that they pull one dagger up & they can potentially fly one rudder a good portion of the time. They also seem to have a relatively small horizontal surface on the dagger.

I my assessment, this all adds up to potential for much higher top speeds without much loss in the less than optimum conditions.

This may be a case, where a plentifull supply of funds and talent can show that just because "no one made it work before" does not mean "it can not be done".

Gooday 'P-F' What a great post - thanks for adding so much of value to this discussion. I'm sure all of us appreciate it - I know I sure do.

Just 'love' your last paragraph. Couldn't agree more. I also try to keep the 'PMA' idea going at all times - 'Positive Mental Attitude' - sure has worked for me. Thanks again - ciao, james

[Doug Lord]

Originally Posted by Doug Lord

Just checked a copy of the preliminary AC 72 rule-no movable ballast, no movable flaps or any kind of flow control device.
Gary must be right(Nah) though I just can't believe a crew could control a 45 or 72' wingsailed cat in pitch.
--
The only thing I see in this preliminary draft is that while the rule specifies that the "bilgeboard" cannot move more than 20mm at its lower loadbearing support there is no restriction, that I saw, on pivoting the daggerboard. If that is still true in the final rule then this may explain how they do it but it would have to be manuallly controlled. Pivot the daggerboard to change the angle of incidence of the main foil. The rudder foil will naturally "trail" the daggerboard: if you can move the daggerboard then you don't need to move the rudder foil.
Boats like the Rave and Osprey are controlled in altitude by "wands"(surface sensors) connected to flaps on the main(daggerboard) foils. While the rudder foil flap can be moved to "tune" the boats pitch angle it is not necessary to move the rudder foil or flap at all- the boat will foil just fine. The Rave was modified by a couple of guys to use a manual control system where a joystick controlled the main foil flaps instead of a wand-they said it worked well. On the AC 45, if I'm right about pivoting the board being legal, it would be a simple matter to design a system that allowed the board to be retractable and most importantly ,pivotable manually. Problem solved.....

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Checked the final version of the rule posted on SA(and below).There is nothing in that version of the rule that prohibits pivoting of the daggerboard as long as it does not translate fore and aft at the lower bearing more than .02m(.78"). There is no reference to the lower bearing being fixed-just that it does not translate relative to the hull(it could pivot w/o translating). There have been foilers that used this exact method to avoid the complication of a flap. I'm more convinced than ever that this is the explanation of how they control the main foil angle of incidence. The board would not have to pivot much and could be designed to move easily even under load. But it would ,apparently, have to be done manually.

Note:
9.4 The lowest load transfering bearing shall not translate relative to the hull,
9.5 A daggerboard shall not translate more than .02m(.78")in the bearing referred to in 9.4 above.
There is a prohibition(9.9) against generating force for the pupose of increasing righting moment but the lee foil doesn't do that and the windward foil is retracted.

[Doug Lord]

From Scuttlebutt Europe today:

ORACLE Team USA Spithill Strong on Day One in Newport


Newport, Rhode Island, USA: It was a frenetic opening day of racing at the AC World Series in Newport, the sixth and final stop on the global international circuit. In glorious conditions on Thursday afternoon, the overall series leader, ORACLE TEAM USA's Jimmy Spithill, extended his lead, while his nearest rival, Dean Barker, saw his season championship hopes sink with a dramatic and unexpected capsize.

Spithill had roaring start in the opening fleet race, powering off the starting line in light breezes to lead from start to finish, giving the American team top seeding in the match racing quarterfinals, which started immediately afterward. Pushed to the limit in the match racing, the team responded to advance to the semi finals.

Conditions were tricky to start the day, with the forecast sea breeze not having filled in by race time at noon. But that didn't trouble Spithill, who extended a narrow lead at the first mark all the way around the race course. A big wind shift late in the race gave the chasing pack some hope, but Spithill held on for what was doubtlessly a satisfying birthday present for the 33 year-old skipper.

Paired against Luna Rossa Piranha, Emirates Team New Zealand unexpectedly capsized in the building conditions. More dramatically, the Kiwis couldn't get their boat upright for nearly an hour, the wing filling with water. At one point, the boat was no longer on its side, but instead had its bows pointing straight up at the clear blue sky, as the boat drifted along in the current. Early indications are that the wing suffered damage in the incident, but the team expects to be racing on Friday.

Friday's program has the one race Match Racing semi finals, followed by a single fleet race. Racing starts at 11:55 EDT Thursday and is live on: http://www.americascup.com/en/Events...cing-Schedule/

www.americascup.com

[Doug Lord]

Highlights of yesterdays racing including Team New Zealand's capsize: www.youtube.com/americascup

Racing schedule http://www.americascup.com/en/Events...cing-Schedule/


Team NZ capsize:

[tspeer]

Originally Posted by Silver Raven

Gooday Doug. I think if you check the records - you will find that 'THE BOAT" - USA 17 - was using water ballast to great advantage in winning the 2 races. Yes/no ???...

No. A water ballast system was installed during testing, but it was removed before the regatta.

[Doug Lord]

Team NZ will reveal their new AC72 next Saturday the 21st of July. Oh boy!
http://etnzblog.com/#!2012/07/big-ni...th-the-big-cat
Time is 5:30pm Sat NZ time-1:30AM EDT


Next racing August 21-26 in San Fran http://www.americascup.com/en/Events...013-AC-Events/

[Stephen Ditmore]

Originally Posted by Corley

SR as far as I know BMW Oracle USA17 trimaran didn't use water ballast. The Alinghi catamaran did but they were so completely outclassed on every point of sail it was hard to judge whether it offered much advantage. Not to mention the incredible racking in the platform on Alinghi under very minor wave action, sure USA 17 racked but it was much more controllable I guess you have to expect some in even a carbon platform thats 90' wide and incredibly lightweight.

In light of this it's interesting that Oracle now employs former Alinghi engineer Dirk Kramers, while Paul Bieker seems to have been bumped.

[tspeer]

Just for the record, Paul has done work for America's Cup Event Authority, which should not be confused with Oracle Team USA. He's not been bumped. I think he has been there and done that, and now prefers not to get totally embroiled in the AC rat race.

Likewise, Morelli and Melvin worked for ACEA to develop the class rule for the AC72 before they got involved with the ETNZ campaign.

[Stephen Ditmore]

Ah, glad to hear it. I do still wonder whether Dirk Kramers was picked up specifically to fill Paul's shoes. Anyway, I'm excited to see what you and all the teams come up with.

[Doug Lord]

From Scuttlebutt tonight:

* The second season of the America's Cup World Series kicks off next month
in San Francisco when 11 AC45s compete for the first time at the venue for
the 34th America's Cup. This event will mark the first time Artemis Racing
fields two teams, and it will be the debut for Ben Ainslie Racing.
Competition is planned for August 22-26. See schedule here:http://tinyurl.com/ACUP-071712

[Gary Baigent]

Just seen the monster AC72 and its monstrous wing ... but as it happened, only took my old Canon rangefinder film camera along ... so you'll have to wait half an hour before I post the digital images.
Anyway, as a taste, looks magnificent.

[Doug Lord]

Originally Posted by Gary Baigent

Just seen the monster AC72 and its monstrous wing ... but as it happened, only took my old Canon rangefinder film camera along ... so you'll have to wait half an hour before I post the digital images.
Anyway, as a taste, looks magnificent.

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Geez, you really know how to hurt an AC freak! Pictures Now! Does it use foils for vert. lift? "L" foils on the rudders? (please!)

[Gary Baigent]

Won't be long Doug. Actually I'd had a meeting again with the harbourmaster about our moorings in Motions Creek (and the power of wealth over us poor sailing boys - the give and take is 95% take on their side, we shift) ... and anyway I just dropped the old Canon in my bag just in case something was happening at Viaduct on my way back ... and there the monster was. I climbed up the corner of the wall and covered gate to get the best shots (I hope). But there are some blurry shots already on Sailing Anarchy ... but mine will be sharper.
Didn't see any lifting foils, Doug, because I had to be quick, but will check closely when the disc comes back.

[Doug Lord]

Originally Posted by Gary Baigent

Won't be long Doug. Actually I'd had a meeting again with the harbourmaster about our moorings in Motions Creek (and the power of wealth over us poor sailing boys - the give and take is 95% take on their side, we shift) ... and anyway I just dropped the old Canon in my bag just in case something was happening at Viaduct on my way back ... and there the monster was. I climbed up the corner of the wall and covered gate to get the best shots (I hope). But there are some blurry shots already on Sailing Anarchy ... but mine will be sharper.
Didn't see any lifting foils, Doug, because I had to be quick, but will check closely when the disc comes back.

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Thanks, Gary. I wouldn't want you to think I was impatient or anything. Nah, not me-I'm so patient I can hardly stand it.....

[Corley]

Beautifully finished boat, here are some photos from the Emirates/Team New Zealand website.