Are you a little confused by all the different types of boats to be built and sailed in the 35^th America’s Cup? Let’s see if we can sort them out.

We’ll start with the race boats for the America’s Cup. The AC62 Class was dropped at the end of March 2015 when the Challenger Committee voted to change the Protocol. Luna Rossa was on the losing side of that vote and promptly made good on their threat to withdraw. The 62 foot long AC62 with a crew of 11 was replaced by a 48 foot long, largely one design yacht with a crew of six. Colloquially referred to as the AC48, the new class confusingly has an old name: “America’s Cup Class.” The hulls, crossbeams and wing planform and section are all tightly specified in the class rule. The design teams have three main areas to be creative: daggerboard shapes, aerodynamics and control systems for boards and for the wing. Protocol restrictions on launch dates mean we will see these boats for the first time in late Summer or Fall 2016 or perhaps not until early 2017.

A smaller, mostly one design boat was touted as a cost saving. In reality, the cost savings are more likely to come from shipping and operational cost than from design savings – designers have plenty of opportunity to be creative with the AC45-based development boats, as you will read below. First, though, let’s look at the race boats for the AC World Series.

The one design AC45’s will race in the AC World Series beginning in July in Portsmouth. A one design foiling package has been retrofitted to the original AC45 design, now called the AC45F. There are no other visible changes – the crew of five still sit on the hulls and the helmsman has a tiller. Camber and twist are controlled with lines on the foot of the wing. The non-foiling AC45 was already a very physical boat. With no grinding pedestals, the AC45F needs batteries to power the daggerboard rake control system, activated by pushbuttons at the helm and just behind the board cases. The horizontal stabilizers on the rudders can be adjusted between races with a worm screw at the head of the rudder, as on the AC72’s.

Now let’s look at the development boats. These boats will not race – they are platforms for testing design ideas and for training. In the turgid prose of the Protocol, these are charmingly called “a yacht allowed in Article 1.1(bbb)(ii).” Not surprisingly, the sailors have other names for them. Artemis Racing calls theirs “Turbo.” Oracle Team USA calls theirs “Sport.” Ben Ainslie Racing uses “T1” for test boat one. Before they withdrew, Luna Rossa just called theirs “Piranha” and “Swordfish,” the same names they had in their former life as one design AC45’s. The Protocol says that long as the lower part of the hulls is the same shape as a one design AC45, you can build whatever you want and modify it as much as you want. BAR’s foiling “T1” uses the standard hulls and crossbeams of an AC45 and looks just like an AC45F, although it surely has some systems in the hulls, out of sight. When last seen, Luna Rossa’s two test boats were also standard AC45 platforms, but with wheel steering and a cut out in the hull where the helmsman could stand.

Oracle and Artemis have shown the most interesting development boats. Both have flared hulls to make room for wheel steering and a grinding pedestal in each hull.  Both have D-section crossbeams that are longer than the standard tubular beams, approximating the length to beam ratio of the now discarded AC62 rule. They also have center pods under the wing like Oracle’s AC72. This was part of the class rule for the AC62 and is in the rule for the 48 footer. The rudder locations are different, and Artemis has two winches per hull – one for the wing and one for the jib, while Oracle has only the wing trim winch. Oracle launched their boat in San Francisco with a full hydraulic control package for the wing while Artemis originally had only the line controlled system, similar to the original AC45 wing controls. Artemis has since added hydraulic controls to their wing. We can only wonder if these boats have electric pumps to provide enough hydraulic pressure for the board and wing controls, given that there is only one pedestal per hull.

While they were in San Francisco, both teams were already practicing manoeuvers and developing crew choreography. Both shipped their development boats to Bermuda and began sailing on the Great Sound in early May.

What will we see in the coming months? Presumably all teams will want to make their development boats as close to the rule for the race boats as they can. The Protocol allows them to build multiple wings for the development boats that are identical to the race boat wings. The limit of two wings for the race boat only comes in to effect when a wing is installed in the race boat. The daggerboards will be so close in size that the Protocol was changed to limit the number of boards that can be built for the development boats. Perhaps most importantly, will it be possible to build an exact race boat deck layout and control systems on top of the lower hull sections from an AC45? Given the importance of crew work in the tight confines and variable winds of Bermuda’s Great Sound, there are big advantages to be had from perfecting manoeuvers early, rather than waiting until you are facing multiple match points mid-way through the America’s Cup Match.

In 1992, both the challenger - Italian syndicate Il Moro di Venezia - and the defender - Bill Koch's America3 - had five America's Cup yachts for test and development. The rules for 2017 attempt to hold down expenses by limiting challengers to one AC62. The defender may build a second AC62 but must race the first one. The rules also forbid sailing "surrogate yachts" - defined as multihulls over 33 feet (10 meters) long. There is an exception: teams may sail up to four boats based on the AC45.

The exception: It's not a surrogate if the hulls are shaped like an AC45

The Protocol allows almost unlimited testing as long as the test boat has the same lower hull shape as an AC45, as your editor explains here and here. Teams will need at least one standard, class legal AC45 to race in the America's Cup World Series. They can build up to three more boats with no limits on wings, foils, crossbeams and systems, as long as the lower part of the hulls have the same shape as AC45 hulls.

A few questions

ACEA announced this week that all six America’s Cup teams have agreed to a project to modify the AC45 catamarans for foiling in the America’s Cup World Series (ACWS). When will racing in foilers begin? Will the foiling AC45's be one design? What wind speed will be needed to foil an AC45? Will the Youth America's Cup be raced in foiling AC45's?

Not news: foiling AC45's in America's Cup World Series

The Protocol already provided for the possibility of changing the AC45 Class Rule and moving to foiling in 2016. At the 9 September press conference Luna Rossa skipper Max Sirena expressed his wish to move to foiling for all AC World Series racing. Three teams, Luna Rossa, Artemis Racing and Oracle Team USA have already modified AC45's for foiling. Each team has made the modifications differently. The trick is to keep the AC45 a one design class and avoid an arms race in AC45 development. This means the AC 45 Class Rule needs to be changed and the boats used for racing must all be modified by the builder, Core Composites. At least six AC45's - one for each competitor - will need to be modified by Core Composites. The question is when - before any racing begins, or part way through the series?

News: agreement to continue the ACWS in 2018

The big news this week was getting all six teams to agree to continue the America's Cup World Series in foiling AC45's in 2018, regardless of who wins the America's Cup. Read more.

AC45's for racing and AC45's for development

America's Cup World Series racing will take place in one design AC45's, with standard hulls, crossbeams, daggerboards, rudders, rigging and wings. Just as the AC45 already has a standard wing extension for light air, perhaps we will see two different daggerboard shapes - one for foiling conditions and another for displacement mode in light air, or for the Youth America's Cup. Each team will need at least one "class legal" AC45 for racing and for their youth team.

For development, the teams will continue modifying other AC45's to test ideas for their AC62. Until the AC62's are launched around September 2016, we may see a lot of interesting AC45 development, as these photos show.

Keeping costs down??

The Protocol strictly limits the number of daggerboards and wings a team can build for their AC62, but allows an unlimited number of daggerboards and wings on their development AC45's. In fact, as long as the lower part of the hulls is the same shape as an AC45, they can build anything they want to test - a boat with wider beam, aerodynamic crossbeams, cockpits and grinding stations, daggerboard and rudder rake controls, you name it.

Different boards for foiling and for displacement mode?

You can be sure all the teams will test a number of daggerboard shapes. Depending on which venue is chosen for the America's Cup Match, teams may need different sets of daggerboards for their AC62 - one set for foiling in moderate to strong wind and another, lower drag set, for displacement mode in light air. Remember how time ran out on Emirates Team New Zealand in Race 13 last September? The wind was at times barely strong enough to fly a hull, let alone foil. Might they have finished within the time limit if they had used lower drag, non-foiling boards?

We'll probably see daggerboards optimized for stable foiling on the one design AC45's. But the teams will test a wide range of shapes on their development AC45's.

If you like the details, keep reading...

The current AC45 Class Rule does not allow wind instrumentation, navigation electronics, hydraulic controls or anything else not on a standard AC45.

Your editor has already pointed out here that the Protocol for the 35th America's Cup allows unlimited development (read "spending") on up to three 45 foot catamarans. Now Oracle Team USA has given us a peek at a design for one of these exotic "development AC45" catamarans.

Limits on sailing AC62's and AC62 "surrogates"

Teams are not allowed to launch their AC62 catamaran until approximately September 2016 - 150 days before the round robin racing begins in the "America's Cup Qualifiers." Nor are they allowed to sail "surrogate yachts" - multihull yachts longer than 33 feet overall - for training, test or development of AC62 components. (They are allowed to race surrogates, e.g. Extreme 40, or use surrogates purely for promotional sailing.)

No limits on up to three "development AC45" catamarans

Protocol Article 1.1 (bbb) (ii) makes an exception to the definition of "Surrogate Yacht." As long as the lower part of the hulls have the same shape as AC45 hulls, the designers can build whatever they want on top. In the OTUSA renderings, we can see that they have designed flared hulls to accommodate cockpits, a grinding pedestal and wheel steering. They have added hydraulics for daggerboard control, an end plate under the wing, and what looks like a pod under the platform. What else have they added that we can't see? Probably wing controls. In addition, rule would allow them to add motors to simulate additional grinding pedestals to provide the same amount of hydraulic pressure they will have available on their AC62 so they can test all their control systems.

No limits on wing sections and daggerboards

Protocol Article 35.7 limits teams to four "AC45" yachts, one of which will need to be class compliant for America's Cup World Series racing. But there is no limit placed on the number of wings, daggerboards or any other component. Wing geometry is tightly restricted by the AC62 Class Rule, but building multiple wings would allow testing of different control systems. Teams can test a maximum of 12 daggerboard sections for their AC62, but any number of shapes on their "development AC45."

We should be seeing plenty of interesting design ideas in 2015 and 2016!

notes:  Protocol w/ amend 1-4

35.10. Limits on Daggerboards:

(a) Each Competitor may build, acquire or otherwise obtain:

(i) a maximum combined total of four (4) one-piece AC Class

Daggerboards and/or AC Class Daggerboard upper sections;

Refer amendment 4

(ii) a maximum of eight (8) AC Class Daggerboard lower sections

provided that such maximum shall be reduced by two (2)

sections for every one-piece AC Class Daggerboard that is

counted in the limit permitted in Article 35.10(a)(i); Refer

amendment 4

(iii) from August 1, 2015, a maximum combined total of six (6)

one-piece Non-AC Class Daggerboards and/or Non-AC Class

Daggerboard upper sections for a yacht allowed under Article

1.1(bbb)(ii); and Refer amendment 4

(iv) from August 1, 2015, a maximum of twelve (12) Non-AC Class

Daggerboard lower sections for a yacht allowed under Article

1.1(bbb)(ii). This maximum is reduced by two (2) sections for

every one-piece Non-AC Class Daggerboard that is counted

in the limit permitted in Article 35.10(a)(iii). Refer amendment

4