Please select your home edition
Edition
Henri-Lloyd 2020 HLRC LEADERBOARD

America's Cup: Italian and British teams reveal first sailing AC75 images

by Richard Gladwell Sail-World NZ 18 Oct 2019 15:37 PDT 19 October 2019
Luna Rossa Prada Pirelli sails their first AC75 off Sardinia, Italy © Luna Rossa

In the past day, two of the recently launched America's Cup teams have released images of their first AC75's sailing and foiling, and apparently doing it well in ideal sailing conditions.

With these shots sailing fans can get some idea of the merits and complete design packages, rather than just ruminating on the nuances and hull shape seen at the launches.

The four AC75's yachts now launched fall into two categories - the Skiffs and Scows.

The Italian Luna Rossa Pirelli have, along with with Emirates Team New Zealand gone for the skiff option, with both using a skeg in the Italian AC75, and a bustle with the Kiwi Defender to provide some low drag buoyancy to help get the AC75 foiling and then soften the touchdown.

As has been seen on the Kiwi boat the reverse bow and increased hull volume performs a vital function in a breeze in a splashdown situation, where the bow kicks in and lifts the boat back onto her foils without too much impact on speed. We haven't seen how the scow approach reacts in this situation, and whether the flat bottomed hull is as forgiving as the skiff.

In one of the images from the Italians, we can see their skeg coming into close proximity with the water, and we would expect to see the same reaction as the Kiwi boat showed in its first video in a similar "water closure" situation. The Italian skeg being more sharply defined than the Kiwi's more rounded bustle, may have to make a deeper intrusion into the water to give the same lift. Which is the better approach remains to be seen.

The scow designs would be expected to have an edge in the aerodynamic stakes, which results in lower aero drag. We saw a similar approach in the 2013 America's Cup with the more aerodynamically efficient Oracle Team USA having the edge over the Emirates Team New Zealand AC72 which had greater hull volume was designed to be able to cope with an upper wind limit of 33kts or more. That limit was dropped to 25kts, and the seaworthiness of the two designs was never really put to the test in racing after racing on several occasions never got under way due to the wind exceeding the variable wind limit of 19.9 to 25.4kts before the start, and on another occasion during the racing.

Wind limits are unlikely to be imposed in Auckland due to the issues that arrive when an absolute threshold is exceeded by just 0.1kt. There is the ability to shift one of five course options and to one less affected area for safety reasons, making wind limits redundant. This is the same approach adopted for the 2009 Louis Vuitton Pacific Trophy when racing was conducted on the final day in quite extreme conditions in the IACC monohulls.

Further the AC75's with their soft mainsail could either make that reef-able or have a heavy weather mainsail. Jibs also come in three sizes, so rig reduction at the top end of the wind range is possible in a way that was not with the hard wingsails of the AC50 and AC72 eras.

No wind limit assures the certainty of TV coverage starting on time, and avoids the crazy sight from the 2000 and 2003 America's Cup boats returning home without racing due to a wind limit being exceeded and ignominiously being towed past Optimist fleets quite happily racing in the "excessive" conditions.

Add in the fact that the Defender is led by two former Volvo Ocean Race skippers to whom heavy air sailing is just part of the game, and the chances of the Kiwis agreeing to a wind limit for the Match is very remote indeed. What the Challengers do for their selection series is their business to some extent. However they would normally sail in the same conditions as the Match.

New York Yacht Club's American Magic and Royal Yacht Squadron Ltd's INEOS Team UK are both in the scow corner of the AC75 rule, and with the video that has been released by the US team and the sill images from both, the show a very clean aerodynamic profile and in that respect, assuming that rigs and foils are equal, would be expected to have an advantage. However, that assumption is something that will never happen in real-life, and we won't know the answer to that question until the first America's Cup World Series event in Cagliari, Sardinia. However, by then the construction of the teams' second AC75's will be well under way.

A rule change allowing the teams to alter both AC75's by 12.5% of the hull surface area could well be significant if changes are to be made after Cagliari ACWS.

Interestingly, the old rule allowed a 25% hull surface area change to the first boat only. But even that degree of permitted change is not sufficient to turn a skiff into a scow, or vice versa. Now it is split evenly between the two boats built by the four Super Teams.

The conundrum for all teams is whether their second AC75 is a Skiff or a Scow - and that is a decision that can now only be made in the simulator. That process can only be done after the teams digitise what they believe are their opponents' designs and then undertake comparative sailing in the world of virtual reality.

The teams then have to make a decision as to whether to build one of each, and then do further testing with the possibility that their first boat could become their race boat.

Or if they opt the for a two skiffs, or two scows, approach. Then they are able to make incremental design changes to refine their race boat to be the best it can be.

Stars + Stripes USA, with one boat from a base Emirates Team New Zealand design is already committed to the Skiff or Scow camp - probably the former.

Related Articles

America's Cup Rialto: Taking on the white water
Defiant was the only AC75 sailing today, docking out just before noon heading for a seabreeze After yesterday's action on the Waitemata Harbour with Emirates Team New Zealand and American Magic sailing in a staged race, today was very tame by comparison. Defiant was the only AC75 sailing today, docking out just before noon Posted on 22 Sep
America's Cup Rialto: Two AC75's race in Auckland
The two AC75's currently in Auckland met up on the Waitemata Harbour on Monday afternoon The two AC75's currently in Auckland met up on the Waitemata Harbour this afternoon for the first shoot-out of the 36th America's Cup. Fortuitously the two teams were both training on Course C. Updated with an amazing 19 minute video Posted on 21 Sep
America's Cup Rialto: AC75's dodge a bullet
Both AC75's were out sailing in Auckland on Thursday, sailing once again in fresh breezes offshore Both AC75's were out sailing in Auckland on Thursday, sailing once again in fresh breezes offshore breezes of 18-20kts, gusting 22kts. The next day, Auckland was hit by a surprise 70kt squall, which gusted to 55kts on Course C. Posted on 18 Sep
Baffling Youth America's Cup decision
Rugby deal raises questions over cancellations of Youth America's Cup and other events Leading sailing journalist, editor and winning America's Cup team manager, Alan Sefton comments on the recent rejection by the Ministry of Business, Innovation and Employment of the Youth America's Cup Posted on 17 Sep
America's Cup: Butterworth joins Challenger group
Brad Butterworth to be a contact figure and facilitate a direct communication flow with the hosts Four times America's Cup winner, Brad Butterworth, joins COR 36, Challenger of Record of the 36th America's Cup presented by PRADA, in the capacity of External and Institutional Relations Officer. Posted on 17 Sep
America's Cup: NZ vessels get new marina offer
Silo & Viaduct marinas offer new deal for NZ vessels and offer bond refund for visitor vessels The official marinas of the 36th America's Cup have tacked in response to a wind shift in superyacht visitation rules - opening 28 berths up to Kiwi vessels at standard rates, while offering overseas boats bond refunds. Posted on 16 Sep
America's Cup Rialto: AC75 gymnastics
American Magic's AC75 Defiant performed some spectacular gymnastics on Monday American Magic's AC75 Defiant performed spectacular leaps and nosedives on Monday - when training in winds well above the racing limit. She recovered from both incidents without capsizing despite the high-risk sailing in winds above the racing limits. Posted on 15 Sep
America's Cup Rialto: Sept 14 - Waitemata Rodeo
One squall came through at 30kts gusting 33kts, catching both teams, luckily ETNZ was under tow One squall came through at 30kts gusting 33kts, which caught American Magic, and she wisely waited it out. But it was the lighter 25kt squalls that appeared to catch Defiant at twice - spectacularly losing control as her rudder ventilated. Posted on 15 Sep
America's Cup Rialto: Sept 12 - The 4 o'clocker
Te Aihe could be seen sailing with what looked to be lighter air sails including Code Zeros. On Saturday, Emirates Team New Zealand left the dock at 1000hrs in a 15kts breeze, which eased during the day back to 10-12kts. Te Aihe could be seen sailing off Auckland's East Coast Bays with what looked to be lighter air sails including Code Zeros. Posted on 13 Sep
America's Cup: Flight of the Patriot
American Magic took delivery of its second AC75 at its Auckland base last Friday New York Yacht Club American Magic, a Challenger for the 36th America's Cup, took delivery of its second AC75 racing yacht at its Auckland base on Friday, September 4th, 2020. Posted on 11 Sep
Henri-Lloyd 2020 HLRC FOOTERUpffront 2020 Foredeck Club SW FOOTERSOUTHERN-SPARS-MISSY-FURLING-BOOMS-728-X-90 Bottom