Thursday, December 27, 2018


You might ask what's up with the 36th America's Cup (AC) going back to monohulls after the highly successful last two AC racing on foiling catamarans? The truth of the matter is everyone knew if New Zealand won the AC their goal was to go back to monohulls as the powers-that-be hated the multihulls. Going back to monohulls was purely a decision of monohull versus multihull mentiality, and because New Zealand won so did the monohull purists.

So the plan now is not just to go back to big beautiful monohulls but to take it a interesting step further and race on 75' foiling monohulls, called the AC75. Yes you read that right, foiling MONOHULLS. Even though the designers of these vessels feel they can be successful with the design there are many well educated designers who feel the opposite. In the end, when the boats hit the water the truth will be known.

The AC75 monohull plan is to have one large wing sail and folding ballasted foils on either side of the boat, and one fixed foil aft. That is the main gist of it, even though there are a lot more smaller details to the design. The wing sails design is well known and so with that knowledge particularly from past AC wing development that is not a big challenge to complete. Team Luna Rosa is developing a new wing sail on an old AC catamaran (see video below at the 5:07 minute mark). However I am hearing some talk of using soft sails, from Grant Simmer of Team UK.

Arguably the biggest design challenge is the forward ballasted folding foils on either side of the hull. The challenge with a ballasted folding foil is it's heavier and thicker profile than the previous thin non ballasted foil on the AC catamarans with thus more drag and having to lift them in and out of the water. The weight plus the increase drag is causing excessive strain on the foils. The new smaller test boats are showing this issues via cracking and breakage. It should be noted the increased drag likely means the AC75's may not be able to foil in as light winds as the previous AC cats. Plus lifting a 1000+ pound foil in and out of the water has its own challenges. One must ask while foiling up wind, while doing a tacking dual if they will be lifting those heavy foils quickly in and out of the water, over and over.

Then there is the issue of stability and avoiding capsizes. It is interesting to note how monohull sailors mocked the AC cats for potential capsizes, and now it appears its a bigger issue on these foiling monohulls. At the 4:17 minute mark in the below video you will see the test boat crash (notice the stabilizing pontoons on either side of the boat and CGI video editing) and Grant Simmer (CEA of team UK) comments about the many capsizes, while not smiling (4:52). The idea of the design is that the ballasted folding foil hanging out of the water on the windward side of the boat will offset the heeling to excess. Problem is the ballasted foil is only so big so its effect on stability will be variable based on wind direction and wave conditions. The AC cats had the advantages of width and length, sailors sitting on the windward side as ballast, plus an inline rear and forward foils. With the AC75 monohull it has limited width, length may have a limited affect, sailors weight is more central, and the foils are offset, i.e. one in the middle on the stern and one to the leeward forward. Maybe they could put two steering foils on the stern to improve stability and steering.

Appears to me due to the noted design challenges they may have to limit racing in stronger winds for safety reasons, and realize foiling in light winds will not be possible and during tacking duals.

So with these noted issues and no doubt other issues that will develop one can only ask if the added cost and challenges are worth going from the proven AC cat to the unproven AC75 foiling monohull. To the unbiased the answer is obvious but to the fixated monohull puriest the obvious is not obvious.

Additionally you might ask what does Jimmy Spithill think about this new class of AC boat? You might also ask what Jimmy has been doing since the last AC as it seemed he dropped off the end of the earth after the last AC. Here is his comments on this topic from his interview with CNN's MainSail programme.

America's Cup veteran Jimmy Spithill has labelled the new boat to be used in Auckland "a beast" that will take the game to "another level" (good or bad?).

Australian Spithill has remained strangely quiet since joining Italian syndicate Luna Rossa after winning and losing the Auld Mug with American billionaire Larry Ellison's Oracle Team USA.

It seems the man who was the dominant skipper in the cup's multihull era  - winning on a massive 113-foot trimaran in 2010, defending on a monster 72-foot catamaran in 2013 and losing in a smaller version foiling cat last year – is intrigued at the prospect of a return to monohulls under the orders of new Cup holders Emirates Team New Zealand.

While the 75-foot foiling monohulls to be used in Auckland 2021 remain on the designers computers, Spithill has garnered enough knowledge from his new team who are the Challenger of Record, to have a good feel for what's in store.

"This one will be another level," he predicted (up or down?).

"It's extreme, it's expensive, from first take, and what we are seeing, it's unstable, and it's going to be very, very physical.

"Will it work? That's the question. The America's Cup has always been at the leading edge of boats. Look at what's happened over the last decade. The AC72 kind of reminds me of this boat in that it is very, very powerful and never been done before.

"The speeds we could have for a monohull… it'll be a beast of a boat. It's out there."

Spithill famously destroyed one of Oracle's AC72s in a capsize in the lead up to the 2013 Cup when pushing the limits under high winds on the San Francisco bay.

He sailed for Luna Rossa in the 2007 America's Cup, skippering their boat in Valencia in the last phase of monohulls. He was at the helm when they lost the Louis Vuitton challenger series final 5-0 to Team New Zealand.

With Oracle out of the frame for the next Cup, Luna Rossa were quick to snap up the experience of the 39-year-old who has been involved since 2000 and has an intimate knowledge of foiling.

He has been used as an on board strategist for Luna Rossa's development phase in the TP52 Super Series which is raced in conventional monohulls and the Italian syndicate is proving highly competitive.

Spithill has also maintained his ties to Australian maxi Comanche, helping them to third in the annual Sydney to Gold Coast race this week, where they frustratingly surrendered their lead 15-miles from the finish as light airs hit, allowing their rivals to catch them.

The first of the new America's Cup boats are due to be launched from March 31 next year 2019.

36th America's Cup takes place March of 2021. I will keep you up to date on the AC75 development.

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