34th America's Cup: multihulls!

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Thanks, Stephen! This time I did save it....

 

34th AC

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Stephen, keep in mind that when the boats are sailing level and IF there is no platform twist it is likely that the nominal 20% of the load carried by the rudder foil at takeoff is split betwen the two rudder foils.
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I still don't think I have enough info to answer your first question last night except to say that there is a good chance that TNZ's main foil is slightly more heavily loaded than the "L" on Oracle. Since we know the foil type is different and has more area I'd say there is a good chance that the foil loading per sq.ft. is less on TNZ.
click-

 

The fore-aft location of the foil affects the stability and the loading on the rudder foil, but I don't think it indicates a difference in approach.

 

34th AC

TNZ back to the water-some glimpses of her new aero fairings:
http://www.youtube.com/watch?feature=player_embedded&v=ygDcD43j5Ds

 

34th AC

Artemis sailing in San Fran:

click- Sander van der Borch pictures for Team Artemis-

 

34th AC

I'm posting this here even though there is a C Fly thread because the claims made for this design are possibly relevant to preventing a hydrofoil from pitchpoling in a seaway:

A Foiling Breakthrough?
As America's Cup Defender Oracle regroups and rebuilds after a spectacular and catastrophic pitchpole, a small team of rocket scientists on this side of the Atlantic is continuing to develop a very different hydrofoil configuration aimed specifically at resolving the problems of foils in waves.

The C-Fly project uses an innovative foil configuration that it's designers claim makes it impossible to pitch pole.

I went to Weymouth to sail her and the cat is our Boat of the Month feature in the current Dec issue of Yachting World

The use of four foils is certainly an unusual configuration. Most surface piercing foilers are arranged in a triangular arrangement where the main foils are forward and the aft foil acts like the tail plane on an aircraft, balancing the boat fore and aft as well as resisting any forward pitching force caused by the rig. The trouble is that if this aft foil lifts out of the water, the stern is no longer held down and the boat can pitch pole. Which is precisely what happened to the French team in 2009.

"Our configuration means that the boat is supported in each corner," he continued. "The further the bows are pressed down, the more foils are immersed and the greater the lift they produce. In fact each foil can exert a maximum of 1.5 tonnes of vertical force at a speed of 40 knots on a boat that weighs around 500kg."

But this is just the start.

"One of the problems with any high speed foil is that of cavitation," explained Richard Varvill. "When a wetted section starts to cavitate you lose control. With the extreme pitching and high angles of attack as the foil hits and breaks clear of the water through waves, we knew we had to design a ventilated foil so that the foil worked without being in direct contact with the water as wetted sections are."

Matthew Sheahan's full report: http://www.yachtingworld.com/blogs/matthew-sheahan/533053/a-foiling-breakthrough

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A bit more on the C Fly: http://www.boatdesign.net/forums/multihulls/c-fly-foiler-40687.html#post594051

 

An ETNZ video detailing the important matters of team beer production.

 

34th AC-TNZ @ 50kts. apparent upwind! 43.6kts boatspeed downwind!

This is a very good article and gives you a sense of what it is like aboard TNZ.
Well worth a read-and there are great pictures:
http://www.sail-world.com/USA/Gladw...n-on-Emirates-Team-NZs-AC72-at-43.6kts/103801

 

I guarantee you that the beer they brewed is leagues/orders of magnitude in quality beyond that of Steinlager, sponsorship notwithstanding ;-)

 

34th AC

Luna Rosa and TNZ on the same water today:

 

Some new shots of ETNZ's AC72 blasting around on the gulf in this Sail-World article.

http://www.sail-world.com/Australia/Americas-Cup:-Emirates-Team-NZ-blasting-in-the-Gulf/103907

 

Doug some more shots for you to make comment.


http://www.sail-world.com/NZ/Americas-Cup:-First-AC72-Practice-Race-takes-place-in-Auckland/103941


4 in fact:

 

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Thanks for that but not one mention of who seemed faster! In the small glimpses provided in the video TNZ looked way faster.
click-

 

34th AC

TNZ on foils:
Chris Cameron photos-click for larger version-

 

Doug and corley are you aware Chris Cameron has posted copyright on his photos.:?::?::?: and only recently.


Chris Cameron/ETNZ©


He might not go you but could go the website 4 allowing it or both.