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44'cruisingcat · 20-11-2017, 23:33

Supposedly faster than the cats, but they have downwind sails? The cats were so fast they were always sailing upwind. If these are faster....

Gonna take a lot of horsepower to move those ballasted foils. Probably going to have similar crew requirements to the cats. A helmsman, a tactician, and a bunch of cyclists.

fxykty · 21-11-2017, 00:18

While a clever solution to generating max power with few people, cyclors were nearly universally deplored and I am sure will be explicitly banned in the next cup. At the launch of the new design there was much emphasis on sailing crews. Especially if all the sails are soft and there will be sail changes. I guess everyone has a nostalgia for the Fremantle 1987 cup contest.

Interesting angle that they’ve introduced trickle down to regular sailing as one of the aims of their design decision to use foiling monohulls.

As for faster, maybe it’s in VMG for the downwind legs? Or just hyperbole to assuage the faster is better crowd that wanted to keep the cats?

PaulinOz · 21-11-2017, 00:45

Thanks for the info Cyan, that was my understanding but was doubting what I thought was the case.

Suijin · 21-11-2017, 04:36

Quote:

Originally Posted by fxykty

As for faster, maybe it’s in VMG for the downwind legs? Or just hyperbole to assuage the faster is better crowd that wanted to keep the cats?

I can see these being faster around the whole course. More maneuverable, probably lighter overall in terms of the hull. I think the premise is that if the boat is flying on foils you don't need two hulls...just put the foil outboard on an arm.

I do have a feeling this may make for some spectacular wipe-outs.

As for the technology "trickling down"..yes, maybe to other racing designs and the odd day sailor but I can't see a cruising foiler anytime soon...

Chuck Hawley · 21-11-2017, 09:50

Is anyone worried about the outcome of a collision between two of these boats when the foils are raised on the windward side? I have an image in my head of someone swinging a scythe in the dark and not thinking about the consequences of hitting someone. Looks like terrible seamanship, but perhaps this is turning into a game of survival.

Chuck

Sailmonkey · 21-11-2017, 10:01

Quote:

Originally Posted by Chuck Hawley

Is anyone worried about the outcome of a collision between two of these boats when the foils are raised on the windward side? I have an image in my head of someone swinging a scythe in the dark and not thinking about the consequences of hitting someone. Looks like terrible seamanship, but perhaps this is turning into a game of survival.

Chuck

This isn’t seamanship, this is pushing the envelope in a one design class. Rules can and will be written to mitigate foil/rigging interactions. But it’s still a sport that is fast evolving.....if it worries you, don’t watch it.

Cheechako · 21-11-2017, 10:22

If it's foiling then I don't think it really matters if it's mono or cat. So whatever works. But I'm sure it must preclude whatever the traditionalist's wanted out of going back to monos. Why not just a grid structure with longitudinal air bags to float until it gets on the foil? Why does it need a hull at all?

Utahsailor · 21-11-2017, 10:26

Cyan: The rules banned closed loop control, but the Kiwis showed the optimum positions from an all but closed loop system on a screen and the the human just lined up a dot with the position and closed the loop with a great deal of help.

I'll bet that they allow onboard power for the foils and require the grinders for normal sail trim.

the raised windward foils are the scariest part- imagine aggressive luffing with those daggers raised to windward.

Chuck Hawley · 21-11-2017, 10:29

Quote:

Originally Posted by Sailmonkey

This isn’t seamanship, this is pushing the envelope in a one design class. Rules can and will be written to mitigate foil/rigging interactions. But it’s still a sport that is fast evolving.....if it worries you, don’t watch it.

Thanks for the kind words, Sail Monkey.

Actually, I have "watched" a lot of sailing tragedies, having been on the inquiry panels of the WingNuts incident, the Artemis incident, and the Vestas Wind incident. I've seen what happens when boats are either unstable, or they come apart and kill sailors. I also serve at the Chairman of the Safety at Sea Committee of US Sailing, and I think every day about how to make sailing less hazardous for offshore sailors. So forgive me if I worry about 75' boats sailing in close proximity with sharp foils above the water.

Chuck Hawley

cyan · 21-11-2017, 13:24

Quote:

Originally Posted by Chuck Hawley

Is anyone worried about the outcome of a collision between two of these boats when the foils are raised on the windward side? I have an image in my head of someone swinging a scythe in the dark and not thinking about the consequences of hitting someone. Looks like terrible seamanship, but perhaps this is turning into a game of survival.

Chuck

Chuck brings up a valid point here. When I zoom in on the image I start to see a blend of Mad Max and Waterworld. Maybe it's just me...

Dave_S · 21-11-2017, 14:36

Quote:

Originally Posted by cyan

Nope.

These boats used MANUAL controls not AUTOMATIC controls.
See section 15.
http://ac.mueva.eu/media/files/m377_...ss-rule-v1.pdf

The rules for 2017 DID allow electric and electronic assisted actuators and valves, however there were specific limitations on these. The main limitation was essentially that no positional feedback was allowed. This is the critical barrier which eliminates any "computer control".

For instance, the rudder system could have an electronic valve that energized a hydraulic cylinder (pressurized by all that human cranking) which applied a specific force to the rudder. You could even SET that force with a steering wheel on board that utilized a pressure sensor. However, the only feedback allowed was for the pressure, NOT the position.

This distinction in the rules forced a HUMAN to complete the feedback loop. A computer cannot decide what to do without knowing the heading, or at least the rudder position. Neither were allowed here, causing the human to always steer. The electronics effectively gave the helmsman extra strength, donated by the cyclists/grinders. This super-human strength was needed to quickly move the rudder, wing, and daggerboard.

Simply put, the delicate touch needed to sail (and fly) was 100% human, and 0% computer.

I LOVE the idea of a race like this which uses incredible technology to go as fast as humans and wind and boat can possibly go without external power or computer controls.
I HATE the idea that this is now the America's Cup, now without sail changes and spinnakers and hiking out and...
(I guess I'm officially ready to be a grandpa?)

Does this apply to steering or steering and foils. 100% human control as the decision maker for the foils must be more than difficult and I would have thought impossible with just 2. I had assumed a computer handled the foils.

Although if I were looking at rules that stated we weren't allowed any positional feed back I'd use stepper motors/hydraulics. By activating the motors with a precise driver you can know where your at without any confirmation and the computer can still make the calls based on knowing where it told the foil to be rather than the foil telling the computer where it is.

I love that the winners draw up the new rules, they are the best people at creating or closing loop holes. It must blow out costs though but how much fun would that be.

cyan · 21-11-2017, 14:52

Quote:

Originally Posted by Utahsailor

Cyan: The rules banned closed loop control, but the Kiwis showed the optimum positions from an all but closed loop system on a screen and the the human just lined up a dot with the position and closed the loop with a great deal of help.

Yeah, good point, Utahsailor! I briefly saw that. I think the rules were written badly for AC50. They allowed force feedback but not position feedback in an effort to make controlling everything purely a manual task. With clever engineering, you could roughly derive position with the inclusion of friction stoppers or other mechanical aids. Most of the 30 designers on the Kiwi team were electrical engineers and hydraulic engineers.

The Kiwis' best move was the cyclors- more power per person, while leaving the hands free to help with trimming. (2 of the cyclors also simultaneously trimmed) One cannot really help trim when one is grinding with both arms, simply for power.

Well done, Kiwis, with a tiny budget and an unusually short time span due to the major one-design size changes. I was rooting for the other boys, but you have to tip your hat to the underdog.
(Unless, of course, we find one day that the harmless-looking blue hydraulic valve case actually contained a little gyro board from a drone.

)
[/QUOTE]

Scotty Kiwi · 22-11-2017, 19:17

Quote:

Originally Posted by a64pilot

Other than if the rules don’t allow it, why not wing sails? Aren’t they the fastest?
I have next to no knowledge about this level of sailing, just a passing amount of aerodynamics.
As I see it a sail is a single surface air foil, a wing sail is I assume a double surface airfoil, and a double surface is more efficient, ask any ultralight person or hang glider.

That's interesting. I've been thinking about the likelihood of wing sails. I looked again and couldn't tell whether or not wingsails were depicted in the animation.

Although they're clearly faster I'll bet against wingsails on the basis of statements about trickle down to other classes of sailing and a desire to not remove the rig at the end of each day.

Are "regular" mainsails more exciting than windsails in these races? Probably not, because the teams pick the sail to use for each race according to the wind forecast, and once the main is up, it is up. It may as well be a wingsail.

The allowance for a code zero for light airs is interesting. That would infer no foiling, but standard yacht racing in light air. NZ's weather is changeable, and that could cause problems for race scheduling and TV coverage cancellation - as happened a fair bit in Bermuda. From memory they needed 12 to 22 knots? A wider window of acceptable race conditions makes the event run better. But this also has interesting connotations for boat design, in that the boats must be able to work in a wider set of conditions. And this also helps with the applicability of lessons to other sailing classes.