Oracle AC72, 25knots + the Famous Bareaway & End of the Story….

Update: Video of the pitch by Andrew Wisner below. No amount of technology, CFD, PhD degrees, and whichever tool and resource you may have can compare with a catsailor common sense.
Sometimes I repeat things too much, but the Bareaways on the AC72 was my first concern, then confirmed even by Grant Dalton (his major concern) and now sadly proven by the slim Oracle AC72.

Someone on the design team needs to get a ride on an F18 and see what happens when you bareaway in +20knots on an Infusion and then try with a another reknown F18.

That will tell you a lot about the dynamics and forces of catamarans no matter the size.

Till now the best prepared 72 for avoiding extreme pitchs in this situation is ETNZ , but I think they went too far on the bow rocker, reducing the needed volume to manage the power of a performance cat, again, whichever the size……

On incoming Mike Drummond’s interview there is a key question related to this… will see his thoughts.
Hope the crew is all OK. Images Robbie Dean / Oracle Racing/Americas Cup. Below report from Oracle Press.
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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.

Acutal Footage of the Pitch by Andrew Wisner

LIVE Broadcast of the Rescue

5 Responses

  1. Anonymous says:

    Much better understanding on bear aways you gonna gain on a Wildcat starting from 18 knots….Infusion? Dead easy…..

    Dom ITA106

  2. Anonymous says:

    The Oracle 72 has so much flex that the windward hull starts digging in before the leeward one.

    From that moment on the leeward hull stops foiling and starts digging in too, and that causes the foils to pull the boat under as well.

    It is like the perfect storm of pitchpoles…

  3. CSN says:

    Well that is EXACTLY the point Dom.

  4. Anonymous says:

    Looks like the foils startet to pull the bows down on some point when the bows went into the water. It maybe foils adjustment issue.

  5. Anonymous says:

    Boat n. 17 probably launched on a friday. It's fearful !