Please select your home edition
Edition
Lizard 2020 - LEADERBOARD
Product Feature
Crewsaver Crewfit 165N Sport (NEW)
Crewsaver Crewfit 165N Sport (NEW)

America's Cup: New AC75 class rule analysed

by America's Cup Media and Richard Gladwell 29 Mar 2018 12:33 BST 30 March 2018
The new AC75 class will feature supplied and one design features © America's Cup Media

The Royal New Zealand Yacht Squadron and Circolo della Vela Sicilia, together with their respective teams Emirates Team New Zealand and the Challenger of Record - Luna Rossa, published the AC75 Class Rule for the 36th America’s Cup today.

The 62 page AC75 Class Rule defines the parameters within which teams can design a yacht eligible to compete in the 36th America’s Cup. It regulates all aspects of the boat to ensure fair and exciting racing, whilst leaving plenty of freedom for innovation to flourish.

The rule is a "box rule" with the overall hull length being 20.6 metres which coverts to 68.5ft and if you add in the bowsprit the length grows to 75ft - hence the AC75 moniker.

Draft with the arms down is a maximum of 5metres. Beam is a little unusual in that it not specified, however the pivot points of the foil arms is specified at 2050mm from the centre giving a distance between the points of 4100mm - the tolerance is extremely tight on the distance between the pivot points - at just +/-2mm per side. The hull outside that measurement looks to be free area, but with little point - just adding drag and weight.

The hull shape is controlled with a couple of beam measurements at points 17m and 19m from the transom where the hull cannot protrude more than 1600mm and 1000mm respectively - the effect is to stop a skimmer or scow type hull being designed.

Building a hull that is too small is countered by a minimum volume "the hull surface shall enclose a volume of at least 70 m3".

Other measurements also apply however within those constraints the hull design is free.

An interesting way of controlling hull alterations is the use of IEGS files which must be submitted when the boat is first floated, and then resubmitted after each alteration. It is then a relatively simple task for the Measurement Committee on a computer screen to check the exact changes made and whether those lie within the allowed percentage change.

The sailmakers are back in business with each boat being allowed 10 mainsails and 29 jibs. The sails in turn are constructed of "skins" which can be replaced and altered.

The mast will be a one design spar to a supplied drawing package and will have two tracks on the after edge of the D-section spar to take the luff rope of the double skinned mainsail.

All standing rigging is also supplied.

The new AC75 is also good news for the carbon batten business with eight battens being allowed per main and jib. Inflatable battens are banned.

The development of the Class Rule has been a four-month process led by Emirates Team New Zealand, working together with Luna Rossa Challenge.

“We are pleased to publish the Class Rule on time as per the Protocol. It has been a detailed collaboration with the Challenger of Record on all aspects of the rule, including the one design and supplied parts. We feel we have done a great job containing costs on certain aspects, while leaving the rule open enough for the America’s Cup to continue as the driving force of innovation and technology in sailing,” said Dan Bernasconi, Design Coordinator for Emirates Team New Zealand.

Highlights of the AC75 Class Rule include:

- Strict limitations on the number of components that can be built including hulls, masts, rudders, foils and sails, thus encouraging teams to do more R&D in simulation and subsequently less physical construction and testing

- Supplied foil arms and cant system to save design time and construction costs

- Supplied rigging

- One design mast tube

In addition, the ‘soft wing’ mainsail concept that has been developed for the AC75 Class Rule is expected to have a trickle down effect on sailing in the future.

The crew size is restricted to 11, without any quota specified for female sailors. The sailing crew must average 90kg with a maximum weight of 990kgs. There is provision for a "guest racer" who can weigh in at 100kg maximum.

The new has extensive provisions about the specification of materials allowed to be used in the hull construction, which is an attempt to control costs of construction and eliminate the use of exotics materials and processes.

Overall hull length must be between 20.600 and 20.700 metres. Maximum draft (with the foil arm lowered to maximum cant angle) is 5.00metres.

All control systems must be operated by the crew by either using a control surface or a control system. It is not permitted to receive "feedback" from a yacht state - ie a sensor or other control on the yacht.

Crews can only use hands as the primary "force input devices".

Foil Cant Systems may only be driven by battery power. Batteries will be supplied.

The hull will feature tight sections which the crew will not be allowed to enter.

“The AC75 Class Rule sets the parameters for the teams to develop and race the fastest sailing monohull on earth. The rules are the result of a close collaboration and a true partnership between Emirates Team New Zealand and Luna Rossa,” said Martin Fischer, Design Coordinator for Luna Rossa Challenge.

“This marks a definite milestone and a turning point from developing the rule to developing the boat,” said Dan Bernasconi. “Overnight we have to completely change our thinking, from trying to write a fair rule, to doing our best to design the fastest boat within the constraints of the rule. We have to stop thinking about what we intended the rule to mean, and start trying to pick it apart for what the words actually say - and see where there might be room to squeeze some advantage.”

This will be the same for the best minds in yacht design and technology across all of the teams who will begin to reveal their innovations 31 March 2019 when the first AC75 yachts can be launched.

The class rule can be downloaded by clicking here

Related Articles

Prada Cup: Hutchinson confirms raceboat rebuild
American Magic confirmed that the team will remain in the Prada Cup American Magic Executive Director Terry Hutchinson has confirmed that the team will remain in the Prada Cup, after nearly sinking their raceboat Patriot yesterday evening in Auckland. Posted today at 2:39 am
Prada Cup: Day 3: Course A - off Barker's place
For Day 3 of the Prada Cup, racing will shift to a new course area off Milford Beach For Day 3 of the Prada Cup, racing will shift to a new course area, in an unusual response to the predicted wind. For the first time in the Prada Cup, Course A off Auckland's East Coast Bays, and North Shore suburbs, will be used. Posted on 16 Jan
America's Cup Rialto: Jan 16 - A day of surprises
Day 2 of the Qualifiers for the Challenger Selection Series, in the 36th America's Cup had as many s Day 2 of the Qualifiers for the Challenger Selection Series, in the 36th America's Cup had as many surprises as the first day of the event. Posted on 16 Jan
Prada Cup: INEOS Team UK scores a hat-trick
Day 2 of the Prada Cup continued to turn the challenger form book inside out. Day 2 of the Prada Cup continued to turn the challenger form book inside out. American Magic from the New York Yacht Club, was widely expected to emerge as top challenger from the Round Robin phase of the Challenger Selection Series. Posted on 16 Jan
Prada Cup: Day 2: Course C - D options
Regatta Director Iain Murray has advised that racing will be held on either Course C of D race areas Regatta Director Iain Murray has advised that racing will be held on either Course C of D race areas today. The breeze is expected to come in later than the 3.12pm start schedule and will be from an average of 230 degrees - or SSW. Posted on 15 Jan
America's Cup Rialto: Jan 15 - Arise, Sir Ben
INEOS Team UK today surprised everyone, perhaps including themselves, with two wins from two races INEOS Team UK today surprised everyone, perhaps including themselves, with two wins from two races on the opening day of the Prada Cup in Auckland. Even more telling the British extended their margin on 11 of the 12 legs sailed. Posted on 15 Jan
Prada Cup Day 1 belongs to British
Team INEOS UK put their stamp on the Prada Cup with two wins on Day 1. Team INEOS UK put their stamp on the Prada Cup with two wins on Day 1. Here's the action as it happened: Shining sun and southerly sea breeze is the theme for Day 1 of the 2021 Prada Cup as the three challengers line up for the first official racing. Posted on 15 Jan
Prada Cup: Challenger Selection Series ready to go
Three Challengers for the America's Cup will compete for the first ever Prada Cup From tomorrow January 15, the three Challengers for the America's Cup will compete for the first ever Prada Cup - one the major International sporting events in the world this year. Posted on 14 Jan
Kiwi grinding veteran on eighth America's Cup
Kiwi sailor Sean Clarkson making an eighth bid for the silverware - but this time for the Americans As the challengers for the 36th America's Cup prepare to square off this week, Suzanne McFadden finds Kiwi sailor Sean Clarkson making an eighth bid for the silverware - but this time for the Americans Posted on 13 Jan
America's Cup Rialto: Jan 12 - Brits on the rise
Ben Ainslie and friends will be sleeping a lot easier after a solid performance in the Practices Ben Ainslie and friends will sleep a lot easier tonight in Auckland, after a solid performance on the two days of practice racing, ahead of the start of the Prada Cup on Friday. Bookies have made a significant drop in the odds for their Parda Cup chances. Posted on 12 Jan