Will foil development win the America’s Cup in 2013?

We have already seen a lot of development work by the AC72 design teams trying to get an edge. Each team is allowed to build 10 daggerboards. Click any of these photos to see it full size.

Testing foil shapes

Alinghi 5 was built for the 2010 America’s Cup

The giant catamaran Alinghi 5 lost to Oracle’s 90 foot wing sailed trimaran USA 17 in the 33rd America’s Cup Match in Valencia in 2010. Alinghi tested S-shaped foils but used straight boards in the races.

You can see one of Alinghi 5‘s S-boards outside the Lake Geneva Museum in Nyon, Switzerland.

Alinghi 5 S-foil

Evolution of foil design for the 2013 America’s Cup

Emirates Team New Zealand

AC72 design - ETNZ launched boat 1 with S-foils. AC72 design – ETNZ launched boat 1 with S-foils.

Emirates Team New Zealand first tested S-shaped daggerboards.

In February 2013 they started testing two different shaped boards with simple curves.

At the launch of their second boat, we could see that ETNZ installed a different shaped board in each hull.

ETNZ tests different shaped daggerboards in their second AC72, launched February 2013.

Oracle Team USA

AC72 AC72 “USA 17” with straight L-shaped daggerboards.

OTUSA started testing straight boards with an L-shape and are now testing a curved board, too. Notice the winglets on the rudders. On the first day sailing, OTUSA broke the starboard daggerboard – no doubt a big surprise to the design team. They replaced it with a modified board from their 90 foot trimaran which won the 2010 America’s Cup.

After their pitchpole capsize in October 2012, OTUSA made major repairs to their first boat and fitted their second wing (the first wing was completely destroyed in the capsize). In this photo you can see the winglets on the rudders, too.

Oracle Team USA repaired AC72 – 1 straight board, 1 curved board.

Prada Luna Rossa

Luna Rossa AC72 straight daggerboard

Luna Rossa bought the design of ETNZ’s first boat, which the rules – unusually – allow. ETNZ got some money, Luna Rossa got a good design and saved a lot of time. ETNZ tested S-shaped boards, but Luna Rossa went with straight L-shaped boards.

Luna Rossa will not build a second boat (all the other teams are building two boats) but they will continue development. We have already seen them testing different shaped boards. In this photo, note that they are also testing the shape of the winglet – the surface that generates lift.

AC72 design - Luna Rossa testing curved daggerboard. AC72 design – Luna Rossa testing curved daggerboard.

Artemis Racing

As of 19 March 2013, the Artemis AC72 is being modified. In a speed test with OTUSA in late February, they were so far off the pace that they decided to make some major modifications.

Artemis’s AC72 was not designed for full foiling. The daggerboards provide enough lift to carry about 80% of the weight of the boat – enough to reduce drag, but not nearly as much drag reduction as can be achieved by full foiling. Head designer Juan Kouyoumdjian has said that while foiling is fast in a straight line, the “transitions” from foiling to “displacement mode” (floating) during tacks, gybes and mark roundings will be more important than straightline speed. Artemis added winglets to their rudders, which foreshadowed their decision to change the design of their second boat to enable full foiling.

Artemis AC72 with winglet on rudder.

Updated 22 March 2013 by Jack Griffin