Well, I hate to admit it, but I *HAVE* been watching the America's Cup and digging into some of the commentary and analysis. Really enjoying it, much to my surprise. Why? I think this one photo sums it up:
- Diagonal Reach
- AC_reverse_leeward.jpg (88.27 KiB) Viewed 14653 times
Negative Leeway! Look at the wakes, these guys are sailing diagonally into the wind (no, they're not in a turn). How is this even possible?!? I may be blasé, but foiling itself is old hat by now. But this? What is going on?!? In this case, it's "simple"... they cant the arms so that one side of the foil is something near 45º to the surface. Now it it produces lift to windward, which can force the boat more towards the wind than the angle it is sailing. Add a little trim - these boats have "ailerons" on their foiling wings - and voila! But doesn't that affect your helm? What helm do you want on these boats anyway, weather, neutral, or lee? It certainly affects drag, your VMG may actually be lowered by sailing diagonally upwind. How to figure this out in real time? By stuffing the boat to it's gills with computers! And that guy in the back of the cockpit with what looks like a red Gameboy Controller - he's the "Flight Controller," in charge of keeping the boat up on it's foils and moving efficiently. So, he's not a tactician? Who's the tactician?!? Now things get fascinating, it depends on the boat but it's basically a "split-brain", everyone feeds their observations to the helmsman/skipper and he decides. Except on the Luna Rossa, where they use TWO helmsmen and swap at each tack...
And there's been actual match racing. Admittedly, most of the races have been won at the starting gun (making the pre-start maneuvers especially fascinating), or at the very latest by the time of the first tack (60 seconds after the start). But even after it's a "horizon job," the sheer seamanship in sailing these things is amazing. And...as Race 8 showed, a "horizon job" is no guarantee, the Kiwis overcame a 4-minute, 2km+ deficit to win by the same margin (an 8-minute swing!). It happened as both boats came off their foils in relatively light winds, but still amazing. Especially in the details - the Kiwi boat came off her foils during a "jibing duel" on a downwind leg... they were nipping on the Italians' heels while both boats were reaching towards the boundary line...no space to pass because of the boundary, so the Kiwis did a quick jibe behind the Luna Rossa... and went straight into their bad air while hitting a light patch at the same time and boom! down off the foils, decelerating from 30 knots to 2 in about 5 seconds. THAT is why they wear helmets and body armor. But.... since when do boats leave a wind shadow UPWIND on a run downwind? Since foiling, apparently. I know they generate so much apparent wind that they are never really running, the wind is always forward of the beam... but the implications are enormous - bad air upwind. Also, despite the flying hulls, or even because of them, drag is a huge component in winning or losing. Case in point, race 7 - the Italians had a slightly too large jibsail for the winds at racetime - maybe 10% larger than what the Kiwis were using. Controlling that sail cost them drag, the drag cost them 2-3 knots raw speed. Despite losing the start and losing the first two legs of the race, the Kiwis won when they managed to slip out of coverage upwind and extend away. Even with the aid of computers, it's still been a sailor's race - just different, very different. Those differences has made the AC worth watching again. And Ok, I'll admit, watching two 20-minute sprints is more "digestible" than watching a 4-hour 1970's vintage race, although I still miss Ted Turner's
Courageous.
Here's some videos, to give you a taste:
https://www.youtube.com/c/PlanetSailOnline/videosan introductory article:
https://www.yachtingworld.com/americas-cup/americas-cup-boats-7-things-you-might-not-know-about-the-ac75s-129881and the official America's Cup youtube channel:
https://www.youtube.com/c/americascup/videosIf you want to watch it live in the US (where it's pay-per-view, and very expensive), then you'll need a proxy server in another country. Use the Opera Browser, it has a built-in free VPN server, simple matter of hitting a button. I'm watching the AC from Finland
Enjoy!