sortius@daycoder @stavvers @Jennifer_Pinkley so, you mean spinnakers? A type of sail.
Smooth moves reply guy
ckfinite@sortius The key difference between these and a spinnaker is how they produce force. A spinnaker is acting as a parachute, producing drag by being blown along by a wind, whereas a kite is flying with the wind. It's a further evolution on the wingsail concept that lets you arbitrarily orient the wing.
The main problem is that it's crazy difficult to control. Flying a kite in all weather is not easy and the system needs to be almost fully automated.
@ckfinite so it's a less efficient spinnaker... which is a sail.
Doesn't matter how you reply-guy it, it's a sail. A sail isn't defined by how it works, but by its purpose
@sortius It's dramatically more efficient than a spinnaker and can work over a much wider range of wind-relative headings. Sure, it's a sail for sure, it just works by very different principles compared to conventional rigging. You can't sail faster than the wind with a spinnaker, for example, but you can with one of these. SP80 wants to go 80kts with one.
The main problem is not efficiency, per se, so much as "keeping the kite from falling into the sea when the sky decides it hates it."
@sortius The benefit is coming from being lifting and from the additional movement of the kite in the wind. The kite then can realize the efficiency benefits of a wingsail on top of seeing a straight-up higher actual air velocity. You can then use this to go faster or to sail more upwind.
The best comparison to a kitesail is the wingsail, which really arose in the 60s. Kitesails have been of interest since the 90s (https://www.jstor.org/stable/pdf/44725651.pdf) but have been cripplingly unreliable.
@ckfinite I like how you've gone from saying "it's not a sail" to presenting straw man bullshit to me.
If they were so good they'd be on every America's Cup boat since the 1960's, but they're not
@sortius That's because America's Cup rules prohibit them from being used. A couple of teams flew them around in 2002/2003 (e.g. https://www.sail-world.com/Australia/Kite-Sails-For-Americas-Cup/-8770) and the rules were changed to keep them out.
Wingsails, sails that are directly attached to the boat but have airfoil geometries, have been used extensively in yacht racing, as in this AC72 class racing yacht whose mainsail uses a rigid airfoil geometry.
Kite Sails For America's Cup
The 2003 America's Cup regattas brought the world's best and fastest high tech sailing yachts to compete in New Zealand, but none more exotic than the USA team's yacht which flew a kite sail spinnaker designed by KiteShip USA during the Louis Vuitton Cup trials, to prove once and for all that regulation designed kite sails could be a decisive advantage in the America's Cup.
@ckfinite you're a joke mate, get in the bin