JumbleDuck
Well-known member
My ignorance on display: Won't whoever loses the cup be Challenger of Record, rather than the team which - effectively - came third?
INEOS AC 2-0
- Thread starter Ningaloo
- Start date
Bobc
Well-known member
The Challenger of Record (COR) arrangement, as it has come to be termed, allows one foreign YC to challenge (becoming the initial COR), that Club agreeing to the terms of the match with the defender and subsequently allowing the winner of the challenger selection series to step into the place of the COR. Prior to 1983, the challengers conducted the challenger selection regatta under their own management and at their own cost. Starting in 1983, Louis Vuitton sponsored the challenger selection, awarding the Louis Vuitton Cup to the ultimately selected challenger. Technically, the eventual winner of the challenger selection process becomes the final Challenger of Record, and win or lose in the match, goes down in history as the Challenger for that America’s Cup match.
So technically you are correct, but I believe that the defender can effectively choose the CoR if there is more than 1 potential coming forward. I might be wrong though.
snk
Well-known member
That's a bit of a puff piece for North Sails. The AC75's mast is a truncated wing using just the leading edge. This rotates and the rotation is controlled by the crew and cane independently set irrespective of the mainsail angle. The mast has twin skin sails attached. It is somewhere between a hard wing mast and a fully battened sail. Fully battened sails do weird things when the luff is tensioned with the cunningham and one consequence is compressing the battens making the sail fuller. The opposite of a soft sail. I think these AC75's can compress the mast with a rope attached tot he mast head. This will induce bend into the mast without tensioning the luff which is tensioned separately. This can do many things like dump the top of the mainsail to reduce power high up or the opposite, induce windwards bend of the the mast top and dramatically increase power. These are highly complicated controls and along with twin skin sails, I doubt very much this tech will 'trickle down' to normal boats.From North Sails:
THE CUNNINGHAM HITS THE BIG TIME
For most sailors watching, a Cunningham is a little string on the luff of the mainsail, just above the tack…
Upon finishing the phenomenal PRADA Cup Round Robin Day 4, packed with lead changes between INEOS Team UK and Luna Rossa PRADA Pirelli, Sir Ben Ainslie described an issue on the boat: Britannia’s Cunningham hydraulic ram failed to work for the entire race. Pre-start, INEOS Team UK had to set it and (hope to) forget it. Ainslie remarked in the post-race interview that his team was “missing one of the key power settings.”
Ken Read, President of North Sails, understood what was happening and why INEOS Team UK was struggling. In this high-performance foiler, the sail plan’s adaptability has become reliant on the Cunningham like as never before; it is now a vital factor in an AC75’s performance. Read took the opportunity to explain how Ainslie’s commentary is related to North Sails Helix Structured Luff technology.
“For most sailors watching, a Cunningham is a little string on the luff of the mainsail, just above the tack,” he said. “You pull it down; it tightens the luff, and that’s your upwind mode. You let it off for downwind mode. Wrinkles/no wrinkles- not a huge speed producer.”
Not the case in the 36th America’s Cup– wherein in this new age of the AC75 foiling monohull, the little Cunningham has a big job.
It takes some serious power, or sail depth, to lift the 6.5-tonne AC75 out of the water. Initially, the AC75 needs massive depth in its mainsail to generate power for lift-off. As soon as the boat is foiling, that depth becomes drag and the mainsail needs to be flat. As the boat accelerates, the mast bends, and a significant part of that bend comes from the Cunningham’s action. Therefore, the sail flattens, and boat speed increases geometrically. Turn the corner and head downwind, and you want some of that power back; the Cunningham gets eased. Rinse and repeat!
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. Throughout the race, the teams will constantly adapt their sail plan up and down the apparent wind range.
On a conventional boat, that would require changing the mainsail’s size by reefing up and down; on the AC75, this rapid, radical control of the mainsail is achieved by applying and reducing extreme tension at the luff– the Cunningham.
The ‘tiny little string’ has become a highly engineered, immensely strong component of the North Sails Helix structured luff system. It is, literally, the leading edge of sail engineering.
North Sails initially developed Helix structured luffs for downwind and reaching sails to enable them to operate in a wide wind range, including partially furled. But the AC75 yachts for INEOS TEAM UK, Luna Rossa PRADA Pirelli, and Emirates Team New Zealand demanded a much higher level of Helix integration.
Ken Read says the innovative Helix design philosophy is changing sail construction and sail trimming forever. “The Cunningham has become the foot pedal that modifies the sail plan to do everything you need in a complicated racing yacht.”
Traditionally, the mast bend is controlled primarily with the aft rigging– from the basic backstay to the most complex runners and checkstay configuration. The Cunningham is used to fine tune. However, if the Cunningham can become the one control to do it all, you greatly reduce drag as well as the complexity (perfect for cruising boats and short-handed boats), in turn, it increases the reactivity (essential for fast boats).
When integrated into a 3Di sail, the Helix structured luff demands a highly engineered carbon fiber taping system, built into the sail’s structure by robotics and then consolidated over a three-dimensional mold. In a complete turn-around from conventional sail-making, the Helix taping layouts within 3Di sails create new ways to look at sail trim across a wide range of shapes. The Helix concept is now available exclusively in sails designed and manufactured by North Sails for both racing and cruising- upwind and down.
It is trickling down, fast, to a sail plan near you.
Ken Read predicts that every sailboat, from weekend cruiser to offshore multihull, will have some form of Helix involved in the future. “That means people will be able to trim sails in ways we haven’t seen before. They will need to learn a few new tricks with these features in the sails, but the efficiency of your sail plan will change dramatically. It will reduce the number of sails you actually need in your inventory. And you don’t have to own a foiler to take advantage!”
Thanks to development on AC75 mainsails such as Sir Ben Ainslie’s, everyday sailors will enjoy more uncomplicated, more powerful sail wardrobes using technology directly from the America’s Cup.
All this was known in the 70's !
Lightwave395
Well-known member
I'm sure you could explain that to Ken Reid better than I could
flaming
Well-known member
CoR is technically the first valid challenge that is delivered to the commodore of the winning yacht club after the AC is won.
What actually happens is that the two teams in the final will have lined up their chosen CoR in advance and broadly agreed the type of class and racing between them, and once their boat is on match point they take the commodore out of public access during the racing, together with the representative of the challenging club, who will hand over the challenge immediately the winning boat crosses the line to win the cup.
In the recent cups this has been achieved by hiding the commodore away on a superyacht to watch the racing, with the representative of the chosen CoR as a guest. Oh, and a TV crew to film it...
This prevents any other representatives from clubs that do not share the defender's vision for the next cup getting in first...
flaming
Well-known member
INEOS came up short against LR, but by a lot less than the scoreline suggests I think. LR were just a tiny bit quicker upwind in the lighter conditions, and seemed to have better tacks.
The opinion of quite a few people who are a lot better informed than me is that the mainsail was the key difference between the boats. Specifically the boomless design on LR allowed better shape low down, which helped with exactly those things, grunt in the light and acceleration. Once the breeze was up, INEOS seemed to have better speed, which suggests that the foils and aero package wasn't terrible.
One of the weirdest things to realise about the AC75s is that they are actually pretty underpowered...
What is most interesting to me is that INEOS had a boomless setup on boat 1, but reverted to a boom for their race boat. I would love to know the thought process behind that,,,,
The opinion of quite a few people who are a lot better informed than me is that the mainsail was the key difference between the boats. Specifically the boomless design on LR allowed better shape low down, which helped with exactly those things, grunt in the light and acceleration. Once the breeze was up, INEOS seemed to have better speed, which suggests that the foils and aero package wasn't terrible.
One of the weirdest things to realise about the AC75s is that they are actually pretty underpowered...
What is most interesting to me is that INEOS had a boomless setup on boat 1, but reverted to a boom for their race boat. I would love to know the thought process behind that,,,,
snk
Well-known member
Ha! No chance. Where the tech has moved to is very impressive. The loads on the rig are unbelievable. Bending that mast even a few cm makes a huge difference and is imperceptible when watching the footage. Trying to find good footage of the the head of the sail in strong winds isn't easy but you get glimpses of a lot of movement up there. I don't think any of the boats were more than a percent apart in speed but some trams have got more data and more sailing time to refine the control systems. I do think this is where Ineos lost out. Prada was doing a lot of sailing in string winds off Sardina, way way back. I'm sure this helped them get the boat to settle and sail fast and smooth. Then they refined this in NZ with improvements in boat 2.I'm sure you could explain that to Ken Reid better than I could
RJJ
Well-known member
I agree - what's the point of a boom when you can make your clew touch the deck?
JumbleDuck
Well-known member
Thanks very much, everyone who replied. I am enlightened. What a bizarre event it is.
Kukri
Well-known member
Perhaps they could not get the very complex systems needed to work reliably? The loads are fearsome, as Mozzysails point out in their explanation of the jerky way that LR’s clew moves.
Lightwave395
Well-known member
Interesting after the event interview with Sir Ben and Grant Simmer:
Snowgoose-1
Well-known member
Did you see his spat about LR and press conference?
Kukri
Well-known member
Yes. He’s not a happy chap. But whether Jim Ratcliffe feels like putting his hand in his pocket for another £150 million may be another matter. Unlike Tommy Lipton, he isn’t flogging anything apart from Grenadiers to consumers.
claymore
Well-known member
Indeed - named after Briggs Cunnigham who also used to race AC Cobras I think, a contemporary of Carrol Shelby (Possibly a predecessor of Thomas
)
Kukri
Well-known member
When I was a boy a Cunningham Hole was used to get a few more races out of an otherwise worn out and baggy mainsail.?
Bobc
Well-known member
First race tomorrow morning.
I think we'll know within 5 minutes of the start.
I think we'll know within 5 minutes of the start.
dunedin
Well-known member
Maybe wasn't competitive racing then?
One event I was at the top 25% of the fleet had new sails measured at the start of the week, and the sailmaker winner used new sails each day! (The rules were changed to prevent that for the next season).
Cunningly used extensively on all the new sails though
Kukri
Well-known member
“I don’t!”?
adwuk
Active member
Only thing I can deduce after all the racing is, whoever wins the start wins. The biggest issue, from a match racing perspective at least, is the fact that the apparent wind is always forward or the beam, so on the downwind legs you don't see the role reversal with the trailing boat able to go on the offensive.
Snowgoose-1
Well-known member
Leaving starting to one side seems in all AC racing so far that each boat will excel in certain wind bands so it's all lottery. As said starting is paramount if you are inferior wind speed. I find that blokes grinding is ridiculous . What skill do you need for that ?