As with the AC72 the vexed issue with the Code Zero is that in displacement mode the Extra is required in marginal conditions to get the AC75 up to foiling speed but once the AC75 is up and foiling the sail is an impediment as the apparent wind comes forward very quickly.

Ac75 apparent wind. Click and drag on the slider bar. The AC75 is not expected to be foiling until windpeeds of 9kts while its predecessor the AC50 could sail at four times the speed of the wind at just 6kts of breeze. There is only 4 degrees difference to the apparent wind from going on the wind to running as deep as you can.

Unless it is stopped dead in the water a boat will never feel the actual true wind. The AC75s are able to lift out of the water and fly in just six knots of wind. But once the boat is foiling the apparent wind speed and angle will change dramatically.

So same on a boat. If you lost the hydraulics while the boats were foiling they would be completely. The fifth yacht planned from the American Stars Stripes challenge has not yet been built and already the challengers and the defender are working on their second yacht which should be launched next summer for the first ones.

Throughout the race the teams will constantly adapt their sail plan up and down the apparent wind range. As the car speeds up the wind increases in velocity and the direction of origin feels like it moves forward. Or cd the angular momentum of the yacht.

The boat feels the new wind generated by its own speed. In mere seconds the AC75 goes from low-speed displacement sailing in as little as 10 knots apparent wind speed to high-speed foiling in excess of 50 knots apparent wind speed. In mere seconds the AC75 goes from low-speed displacement sailing in as little as 10 knots apparent wind speed to high-speed foiling in excess of 50 knots apparent wind speed.

Although the boats will be foiling most of the time it is going to be incredibly important to have a hull which gets you foiling as quickly as possible Bernasconi says. As explained in the article a year ago the hull of an AC75 in foiling mode should have zero lift zero heel and almost zero distance between the bottom of the hull and the water surface. Throughout the race the teams will constantly adapt their sail plan up and down the apparent wind range.