| Re: AC72 Oracle Team USA Spaceship has landed
[Re: samc99us]
#253620 10/18/12 04:47 AM 10/18/12 04:47 AM |
Joined: Feb 2005 Posts: 4,118 Northfield Mn Karl_Brogger
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Posts: 4,118 Northfield Mn | What are the bets on seeing this thing fly again? ah, google Larry Ellison. He has almost more money than god. It'll be on the water again ricky-tick I'm sure. Hell, a local company just spent $31m on an Oracle product, so that should help.
I'm boatless.
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: Karl_Brogger]
#253623 10/18/12 06:38 AM 10/18/12 06:38 AM |
Joined: Jun 2001 Posts: 3,906 Clermont, FL, USA David Ingram
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Posts: 3,906 Clermont, FL, USA | Your fascination with poo is disturbing.
David Ingram F18 USA 242 http://www.solarwind.solar"Do or do not. There is no try." - Yoda "Excuses are the tools of the weak and incompetent" - Two sista's I overheard in the hall "You don't have to be a brain surgeon to be a complete idiot, but it helps"
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: P.M.]
#253624 10/18/12 06:45 AM 10/18/12 06:45 AM |
Joined: Feb 2005 Posts: 4,118 Northfield Mn Karl_Brogger
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Posts: 4,118 Northfield Mn | BWAHAHAHAHA! That avatar is high-larious!
I'm boatless.
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: P.M.]
#253627 10/18/12 07:29 AM 10/18/12 07:29 AM |
Joined: Feb 2005 Posts: 4,118 Northfield Mn Karl_Brogger
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Posts: 4,118 Northfield Mn | I would watch that as an Olympic sport. Especially if they toilets were set up like hurdles.
I'm boatless.
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: Team_Cat_Fever]
#253631 10/18/12 09:24 AM 10/18/12 09:24 AM |
Joined: Feb 2009 Posts: 43 where the wind never blows Lockenfisch
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Posts: 43 where the wind never blows | ...You can't push the development edge that hard without some consequences. Sorry but multihulls pitchpole and break their riggs eversince... its just bad luck if you, me, Oracle or someone else will be the next one day ;-) Here it looks to me as if the recovery and the counteraction to not let the mast, wing go down was too slow. Maybe they had just no idea, never planned that?
Last edited by Lockenfisch; 10/18/12 09:25 AM.
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: Lockenfisch]
#253632 10/18/12 10:00 AM 10/18/12 10:00 AM |
Joined: Dec 2001 Posts: 5,590 Naples, FL waterbug_wpb
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Posts: 5,590 Naples, FL | do you think the foils may have hurt the hull's ability to recover from the nose-dive during the turn down?
Since those things aren't adjustable, I would figure at some point the foils were actually trying to dive for lobster along with the bows...
And having 131 feet of wing pushing didn't help, either...
Jay
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: waterbug_wpb]
#253637 10/18/12 12:50 PM 10/18/12 12:50 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | do you think the foils may have hurt the hull's ability to recover from the nose-dive during the turn down?
Since those things aren't adjustable, I would figure at some point the foils were actually trying to dive for lobster along with the bows...
And having 131 feet of wing pushing didn't help, either... Those foils must have had incredible loads on them during that event...and you would think that when those lifting boards point to the bottom that they drive harder to the bottom. I heard mention that the foil loads tore up the hulls during that dive and they didn't even know if the hulls were repairable.
Jake Kohl | | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: Jake]
#253638 10/18/12 02:12 PM 10/18/12 02:12 PM |
Joined: Jan 2005 Posts: 105 Bloomington, IN jbecker
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Posts: 105 Bloomington, IN | Also, the main L-foils at that high negative angle of attack must have produced a lot of drag and contributed to slowing the boat, so in addition to pulling the whole boat down, they contributed to the torque loads that forced the bows down.
It will be interesting to see what design changes come out of this. I'm picturing main foils with super strong hinges so that the L-foil part swings to near vertical when top loaded, and back to horizontal under normal upward loads. I wonder if such a thing is possible with modern materials, and if the drag and weight of such a hinge would be acceptable. It would not be an angle of attack control per se, so it seems like it might be acceptable under the rules.
Jeff Tiger 849
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: P.M.]
#253640 10/18/12 03:01 PM 10/18/12 03:01 PM |
Joined: Jan 2005 Posts: 6,049 Sebring, Florida. Timbo
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Posts: 6,049 Sebring, Florida. | We all have had the same problem at every bear away, think A mark in a good blow, many times with the same results (pitchpole). As you turn from going upwind to downwind, you've got several additional forces all happening at once, to include the centrifical force the rig exerts as it's being swung in the big arc, the added drive from the (momentarlily, until you accelerate) greater aparant wind which is now puhsing the bows down, not lifting the windward hull up, and the added drag of going faster, on the boards which also pulls the bows down, until they get into foiling mode. From watching that video several times, it looked like a classic bear away nose dive. As they bear away and unroll the jib, the bows go down and never really come back up...they just keep going deeper and deeper as they accelerate, until it's too deep to recover. Use full screen to see this: http://www.youtube.com/watch?v=drgglIebuQY On our boats, we can all run to the back, to keep the bows up when we get to A mark and we know it's coming, but they can't shift as much (relative) balast aft, as we do in that situation. I still think it needs more volume in the bows to help prevent this nose diving. That was the cure for the early Blades, as well as some of the A cats. You may recall years ago, when the mega cat Playstation had to have it's bows modified, enlarged, etc. The first time they took it out in big wind and waves, they also stuffed the bows and nearly pitched it right over. The only beach cat I've felt 'safe' on in a big wind bear away was the Inter 20, and it's known for it's huge, fat bows. When I look at the design of the AC72's, I see A cat like, skinny bows. Great for keeping weight off...but not so good for preventing a picth pole. Remember, they cannot simply 'dump the main' when it gets blowing too hard and you want to bear away, like we can. If they are going to keep going out in 25knots, they'll need bigger bows, or a much better righting system! It looked very similar to this earlier pitchpole, on the 45' version, nearly identicle; http://www.youtube.com/watch?v=-KNql99zT6s Now, watch this next video of the first sail of Oracle 17. Pay particular attention to what the bows are doing, they always seem to be pointing down. Near the end of the vid. at 1:50, they are just cruising back to the dock, not pushing it, not even blowing too hard, but going downwind, and the bows are looking like they want to dive. http://www.youtube.com/watch?v=Sr055W97l4o Go to 'full screen' you'll have a better look.
Blade F16 #777
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: P.M.]
#253642 10/18/12 03:47 PM 10/18/12 03:47 PM |
Joined: Jan 2005 Posts: 6,049 Sebring, Florida. Timbo
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Posts: 6,049 Sebring, Florida. | I can hear them on the docks now:
"Hey...get some Duct Tape! And HURRY!"
Blade F16 #777
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: waterbug_wpb]
#253646 10/18/12 07:36 PM 10/18/12 07:36 PM |
Joined: Jun 2002 Posts: 1,658 Florida Suncoast, Dunedin Caus... catman
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Posts: 1,658 Florida Suncoast, Dunedin Caus... | do you think the foils may have hurt the hull's ability to recover from the nose-dive during the turn down?
Since those things aren't adjustable, I would figure at some point the foils were actually trying to dive for lobster along with the bows...
And having 131 feet of wing pushing didn't help, either... They are adjustable. They can adjust the angle of attack. There is a learning curve here and they missed the setting for the conditions at hand. If you check out Sailing Anarchy ,Tide Tech shows that the conditions changed when they made that last bear away. Had they had the time or knowledge to set the foil properly they may have been alright. They are not counting on forward buoyancy to keep the bows up. They are counting on the foils for that.
Have Fun
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: rehmbo]
#253649 10/18/12 09:39 PM 10/18/12 09:39 PM |
Joined: Jun 2001 Posts: 12,310 South Carolina Jake
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Posts: 12,310 South Carolina | So is the lesson then to travel-in when starting to stuff as the apparent wind shifts aft? Part of that makes sense, but when the apparent wind is at 90°, It would be really tough to override the instinct to dump the traveller. Not sure I'd have enough time to think about it... Past a certain point, you are just screwed. IF you can keep your speed up through the turn you are better off as you apparent wind will remain more forward. When the boat stuffs hard enough to go over, I don't think anything you can do will save it. Sail in, sail out, it's only going to change the angle with which the mast hits the water. Once it stuffs, the momentum and wind pressure are working against you and you have no helm. I've been out where it took three or four attempts to bear away to get through the turn. The trick was to get through the turn as fast as the foils would let you when the waves and wind are just right. The faster you can make that turn, the better off you will be. Get your speed as fast as possible, hang on, and yank it through hopefully just short of your rudders stalling. These guys were just hugely overpowered and as they bore away, the rudders were probably stalled and about 1 second later and another second after that, there wasn't enough rudder in the water to have any influence over the direction of the boat. That wing is ONE HUNDRED AND THIRTY FEET TALL!!! That's a lot of tomahawk momentum!
Jake Kohl | | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: P.M.]
#253651 10/19/12 12:34 AM 10/19/12 12:34 AM |
Joined: May 2006 Posts: 1,383 Kingston SE South Australia JeffS
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Posts: 1,383 Kingston SE South Australia | There was a thread on here a long time ago about a guy that made a CO2 cartridge with balloon that you could inflate to stop a mast turtling, would something like that have stopped this wing filling with water which stopped the righting?
Jeff Southall Current boats Nacra 5.8 1703 Animal Scanning Services Nacra 5.8 1667 Ram Raider Nacra 18 Square Arrow 1576
| | | Re: AC72 Oracle Team USA Spaceship has landed
[Re: JeffS]
#253652 10/19/12 02:44 AM 10/19/12 02:44 AM |
Joined: Feb 2009 Posts: 43 where the wind never blows Lockenfisch
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Posts: 43 where the wind never blows | There was a thread on here a long time ago about a guy that made a CO2 cartridge with balloon ... you can buy one. Just search for: Secumar Auto Inflation Anti-Inversion Mast Float Somehow not very common. I've never seen a boat equipped with it. Propably because getting a beach cat out of the 100% turtle position by manpower is not so difficult, as far as the boat is not too wide like Tornado, H21, or others. That "airbag-recovery" could work on any boat I guess. | | |
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