So when an AC75 is sailing upwind in 18 knots of breeze at a boatspeed of 40 knots the crew on deck will be experiencing 40 knots of wind over the decks plus a percentage of the true wind speed.

Ac75 upwind angle. The AC75 feels like a big Airbus jumbo jet. When drag angle of the hull is negligible the formulas for calculating V A and β are. AC75 capable of 5x windspeed - apparent wind angle 115 deg AC50 capable of 4x windspeed - apparent wind angle 143 deg windsurfer and blokart and AC62 capable of 3x windspeed - apparent wind angle 191 deg.

Emirates Team New Zealand have a different method. A upwind 90 on port tack for X 22. On Thursday 19th November Emirates Team New Zealand were the last team to launch their second AC75 the boat on which the Kiwis will defend the 36th Americas Cup over the period March 6 to 21 2021Three weeks before the start of the Americas Cup World Series in Auckland Tip Shaft interviewed Martin Fischer co-design coordinator at Luna Rossa Challenge and Benjamin Muyl chief.

Normal downwind speeds on the Vampire are 20-25 knots on the AC75 35-50 knots. The visually diverting aspect of the AC75 is the foil each side which will serve alternately as a hydrofoil generating lift and as a lever producing righting moment. From 25 to 38 knots downwind.

Upwind the AC75 will need to build speed by coming off its optimal VMG upwind course for some time and may have to sail a reaching course to some degree Eventually speed will build and from a rig point of view while reaching sheets will be eased a little and come back on as the boat pops up. V A square root V T cos 90 true wind angle 2 V T sin 90 true wind angle V B 2 β 90 arctan V T sin 90 true wind angle V B V T cos 90 true wind angle Sail power. The peak downwind speed on the Vampire is 35 knots but we have yet to see 70 knots from the AC75s and cavitation problems may make it.

Foils aside the AC75 is a relatively normal monohull with a conventional hull a rig that is not dissimilar to other high-performance yachts and will be sailed with a crew of 12. Lining two boats up beside each other and sailing as fast as possible but with both boats constrained to a straight-line either upwind or downwind for 10 minutes at a time. This thing is very locked-in and smooth.

On the flipside the same effect may mean the trailing boat needs a bigger wind shadow to slow it down so the effects could cancel out. Your goal is to get the mast straight with 20 degrees of heel. When sighting mast bend position your eye just above the gooseneck on the aft side of the mast and look straight up the mainsail luff groove.