Artemis Mea Culpa

Wow. In the world of Americas Cup racing you hardly ever hear straight talk about what's happening, especially after major setbacks. So kudos to Paul Cayard for giving Scuttlebutt's Craig Leweck an EXTREMELY (at least in AC terms) candid update on how wrong Artemis got the foiling issue, how much catching up Artemis has to do, and how they are going about it. 

Here's a taste:

Sailing against Oracle was a full-scale verification that we needed to make some pretty big changes, and that's what we are doing. We are taking it on. The good news is that we learned this in February and not in July. So we have some time to react. But we need to commit more to foiling.

When discussing foiling, it is important to understand that it is not black and white. It is a spectrum, and what we are really saying when we say 'foiling' is that we are reducing displacement of the boat. The lifting occurs through the foils on the rudder and the daggerboard design. On a spectrum between zero and the full weight of the boat, a fully foiling boat is lifting the full weight of the boat.

Our boat had J boards, and while they lift a percentage of our displacement, they do not lift all of it. The game of foiling is trading off the drag associated with the boards. The fully foiling boats use L boards, but both the surface area of these boards, and the tightness of the L board angle, create more drag than the J board. However, they also cause more lift.

So each team's design tools predicted what the cost of the drag would be, and what the benefit of the lift would be, and it is fair to say that we got it wrong. So now we are reacting. Our team has come together, and is fully committed to tackling this issue full on. 

There's lots more, and you can read the full thing here. It's a must-read on how the teams have been thinking

about foiling and the trade-offs.

Here is the training session in which harsh reality knocked the Artemis team off its tracks.

And, for comparison, here's how ETNZ is looking: