34th America's Cup: multihulls!

[Doug Lord]

34th AC

Eyewitness act. from SA: by JAG

"I just happened to pull up the St.FYC webcam about 20 seconds before the capsize. They were coming upwind on port tack a little below the yacht club. They had both hulls in the water like they were taking a breather (sailing relatively slow). They they accelerated on an upwind point of sail heading towards the middle of the bay. When they turned down through the 'zone of death' with barely any heel, the bows started to dig and spray started flying everywhere. It didn't appear like they were unfurling the Code 0. Even with the jib blown, the boat continued to pitchpole in what seemed like slow motion. It probably took 7 seconds from when the bows dug in until the wing hit the water. I couldn't tell on the webcam if anyone flew directly into the water on impact. One other observation, it did not appear like they were unfurling the Code 0 during the bearaway.

Glad to hear everyone was alright! "
=================
Picture from the Weta Trimaran facebook page:
click on image-

 

[Doug Lord]

Oracle capsized

Live coverage here: https://www.youtube.com/watch?feature=player_embedded&v=3ua2puIu4Kk

NBC San Fran coverage: http://www.nbcbayarea.com/news/local/Team-USA-Oracle-Boat-Capsizes-in-Bay-174485331.html

 

[Doug Lord]

Oracle pitchpole

Found on SA:

MEDIA ALERT: ORACLE TEAM USA 17 Capsizes During Training in San Francisco
San Francisco, Tuesday, October 16, 2012
SAN FRANCISCO - ORACLE TEAM USA 17 – the team’s AC72 racing yacht – capsized during training at approximately 3 pm PT today on San Francisco Bay. All crew and ORACLE TEAM USA team members are safe. It was the boat’s eighth day on the water since the launch in August.

Said tactician Tom Slingsby of the capsize:

“We called for a bear-away as we were out training. The winds were blowing about 25 knots, and there was strong ebb current at the time. We started the bear-away, and as the boat accelerated it pitch-poled.

“We didn’t know what was going to happen with the new boat. When the nose went down, the wing hit and a few guys went in the water. We were unsure if the wing would snap, so we all climbed off the boat.

“Luckily, everyone is accounted for and no one was hurt. The wing is pretty badly damaged, and we are working to get the boat back in position to return to Pier 80.”

The crew and boat will return to the team base at Pier 80 in San Francisco and assess the situation further. Additional details and images to follow.
--

 

[Doug Lord]

Oracle pitchpole

ABC SAN FRAN Live:
http://abclocal.go.com/kgo/livenow?id=8849852#&cmp=twi-kgo-article-8849852

 

[Corley]

Another article on the capsize at americascup.com

http://www.americascup.com/en/news/3/news/8482/oracle-team-usa-capsize-ac72-on-san-francisco-bay

 

[Stephen Ditmore]

If they need help rebuilding that wing I recommend the ornithopter team:
http://hpo.ornithopter.net/?q=team
(along with the Object 2 Skiffworks team + Rossi Milev + their regular cast).

 

[Doug Lord]

Oracle Capsize

I gather that she's drifted thru the Golden Gate bridge and is way on the Pacific side of the bridge. Not good-such a damn shame.....

 

[Stephen Ditmore]

Perhaps it's headed for Lanai...

 

[Doug Lord]

Oracle Capsize

Here is the capsize caught on video:
http://www.youtube.com/watch?feature=player_embedded&v=drgglIebuQY

 

[Gary Baigent]

Twist, too much twist, (how long have we been saying that?) twisted windward hull crashes down, total low volume bow(s) bury ... end of story.
Even in that video a couple of days ago, taken through public viewing telescope, Oracle looked horribly bow down and wrong, creating large areas of white water.
Sad to see all that boat building time and effort lost - luckily the capsize was so slow, no one was hurt.

 

[groper]

Ouch... the whitecaps show some pretty decent wind there...

Watching the lee bow submerge, its stays under for a good 100m before it passes the point of no return... makes me wonder if the foil angle was too negative at the time...

 

[HASYB]

Whow...impressive slow pitchpole. luckily no one hurt.
Kind of strange to see Oracle 17 "submarining" like what seems to be forever, before "finally" turning over.
It looks caught in a situation. Rather than twist it looks as if they turned the corner to fast and the windward hull submarined.
Did something break before it going in "submarine mode"?
Any one of what could have been done to avoid turning over in similar situation next time?
Is it possible deploying some sort of breaking chute on the stern to instantly reduce speed and save the situation.

 

[Gary Baigent]

Not carrying a headsail MIGHT have helped - but horrible platform twist and too low reverse bows screwed this boat, also the pod didn't help either. Course this will be vehemently denied ... by the deniers.

 

[SteveMellet]

Deploying an emergency chute / drogue off the back would only load up the rig faster and accelerate the pitchpole.
I'm with Gary on this, the design was all wrong from the start. When the first video of it trying to foil came online, as the leeward hull started to fly, the windward hull dropped quite suddenly and slammed quite hard, I wondered how long the t-foil rudders and the L-board would take this abuse before something broke. When they attempted the bearaway the boat accelerated and the windward hull dropped in again, this time with the nose pointing down due to the racking platform. Lifting foils don't lift if they're pointed at the bottom of the bay. The windward foil then did what it was designed to do at that angle of attack, which was to be a handbrake.
Oracle got the design totally wrong, there's no amount of patriotism should be able to convince you otherwise.

 

[groper]

i must admit, initially i thought the design may have been very clever by allowing the twist to complement the control - but now it seems more like an Achilles heel.

Think about it, how many different permutations of wind speed, boat speed, tack angle, foil angle, sail trim etc yield a different rig loading, and thus platform twist angle? How does one account for such a broad range of loadings and manage to manually control the flight when 2 hulls in the water, flying a hull, and all the time compounded by foil and rudder angles changing all the time with the twisting??? with bloody good luck is about all i can imagine!! Add a decent breeze, and one little mistake ends it all REAL QUICK.... a successful platform will need a good amount of inherent stability particularly with regard to longitudinal pitch or it has little chance of making it round the course in 1 piece, let alone winning a cup...