America's Cup: Will crucial Cup design decisions be determined in Cagliari?
by Richard Gladwell/Sail-World.com/nz 5 Feb 2020 13:23 AEDT
5 February 2020
NYYC American Magic training in Florida - January 17, 2020 © Will Ricketson
The first battle for the America's Cup World Series will take place at the end of the April in Cagliari, Sardinia and will be a strong design indicator for the Main Event nine months later.
The World Series regatta will be the first opportunity to get an answer for the skiff versus the scow hull question.
Two of the teams (Luna Rossa and Emirates Team NZ]have opted for the skiff design concept. The other two teams (INEOS Team UK and NYYC American Magic) have opted for the shallow bodied scow design concept.
The sting is that all teams will have made a commitment to the concept of their second AC75 well before the outcome of the series is known. If the battle of the four first generation AC75's determines that one hull shape is decidedly superior to the other, then for some, 2021 could be a very long summer in Auckland.
To date the three Super Teams have been quite guarded - epitomised by the paucity of video content of their AC75's that has been let go into the public purview.
The Defender, Emirates Team New Zealand has been the most open, but has had their hand forced by the amount of amateur video circulated through cyberspace by Kiwi fans. Before Christmas the Kiwi team let go video of a splashdown shot from a drone, and backed that up with video of their spectacular capsize on December 19.
The key question for Cagliari is over the two differing hull types - the flatter bottomed scow approach favoured by NYYC American Magic and INEOS Team UK, versus the V-shaped hull of the skiff option chosen by Emirates Team New Zealand and Luna Rossa.
In a podcast from the Road to the America's Cup series, INEOS Team UK skipper Ben Ainslie commented "the American boat is similar to our boat. I think it is maybe not a co-incidence that ourselves and the Americans have taken a slightly different path to the Kiwis and the Italians in terms of how much knowledge they had of the concept of boat we had before putting down the hull designs for Boat 1."
"That is more of a boat that is based around being in displacement mode and using that hull form to help accelerate in displacement mode and then go into lift off. Our boat is like that.
"There are some interesting considerations as to how all the boats perform out of the water and the blister effect on the Italian boat and the Kiwis. Our boat and the American boat don't have the blister, but they have more effective surface area, so what are the trade-offs there in terms of the end plating to the surface of the water. "
Ainslie's point is that the scow shape is orientated to get the AC75's foiling as quickly as possible, without requiring a heavy hand on the flight control systems to force the AC75 into flight mode. That would increase drag and have a negative effect on boat speed.
Last week Ainslie's team INEOS Team UK took the refreshing initiative of releasing the video of their AC75 making a splashdown which training off Cagliari, Sardinia.
Initially it was a regulation nose dive. The AC75 reared up high on her foils, which as photographers of the America's Class know is the time to start pressing the shutter button ready for an almost inevitable and spectacular re-entry, a scene best captured using a wide-angle lens.
A second or two later, Britannia duly obliged, with a massive splashdown with the spray reaching almost a third of the mast height.
But instead of tracking straight ahead Britannia suddenly turned 90 degrees to port. Many would have expected a capsize, but thankfully not and the AC75 came to a very wet halt, with her jib flapping.
A high performance skiff sailor, subsequently spoken to by Sail-World, maintained that any apparent wind high performance boat would have nose dived or similar in the same spectacular way to the Brits, if they made the same course alterations as INEOS Team UK. He also noted that the sails didn't appear to be fully powered up, and in the video the jib leech looked very twisted open, and was luffing in its forward section.
All of which indicates that things aren't always quite what they seem, and there are explanations for many AC75 issues which are at odds with the apparently obvious, or simplistic.
In the course of a wide ranging interview on PlanetSail with Matt Sheahan, Luna Rossa Prada Pirelli designer Martin Fischer discusses the AC75 design issues.
Responding to a question as to whether Luna Rossa had joined the capsize club, whose founder member was Emirates Team NZ's AC75 which launched clear of the water following a gybe and then slowly rolled into a capsize.
"Not yet - I'm hoping we can avoid it [a capsize]. But it will happen one day, for sure," he replied.
"In my opinion all the teams will capsize sooner or later," Fischer added.
"It was not a big drama. They had the boat up in three and a half minutes and continued ..sailing. There was no damage.
"You will try and avoid it obviously, but it is not a catastrophe - like it was with the AC72, for instance. It was a disaster when they capsized. That is not the case here."