AC45

AC45
Name	AC45
Type	Racing catamaran
Length	13.45 m
Propulsion	Wing sail

AC45

The AC45 is a 45-foot high-performance one-design foiling catamaran introduced as an international racing platform for the America's Cup ecosystem and global match racing circuits. It served as a bridge between traditional keelboats and the wing-sailed foiling classes used in elite events such as the America's Cup World Series, the Louis Vuitton Cup, and the America's Cup campaigns of the 2010s, enabling teams from organizations including Oracle Team USA, Emirates Team New Zealand, Team New Zealand, Artemis Racing, and Groupama Team France to develop foiling tactics, crew work, and aerodynamic tuning.

Design and specifications

The AC45 was conceived under technical parameters influenced by the International Sailing Federation frameworks and the design philosophies of leading naval architects who had worked on prior America's Cup entries such as BMW Oracle Racing boats and designs from Luna Rossa Challenge. The platform measured 13.45 metres overall with a beam that allowed for wide trampoline decks and high righting moments similar to multihulls designed by firms tied to VPLP Design and Sethus design houses. Its rigid wing sail reflected advances used in the 2010 America's Cup and later campaigns involving full-scale wings like those on BMW Oracle Racing 90, trading traditional soft sails for an articulated, cambered aerofoil with control systems inspired by aerospace companies linked to teams such as Oracle Team USA and Emirates Team New Zealand.

Construction techniques incorporated composite materials commonly used by teams such as Groupama Sailing Team and yards that had built for Artemis Racing and Synergy Russian Sailing Team, blending carbon fibre monocoques, honeycomb cores, and high-modulus spars derived from suppliers who also worked with Malizia and Alinghi. Foil technology included daggerboards with T-foils and lifting surfaces that echoed developments from experimental craft in events like the Volvo Ocean Race and prototypes seen in trials by Luna Rossa.

Development and history

The AC45 emerged as part of a strategic move by the America's Cup Event Authority and stakeholders to create a standardized class to broaden participation beyond in-house development programs such as those at Team New Zealand and Oracle Team USA. Initial design work drew on lessons from the 2007 America's Cup and 2010 America's Cup, when multihull experimentation accelerated after entries from syndicates including Alinghi and BMW Oracle Racing. Launches and commissioning for many teams involved collaboration with shipyards and designers associated with Cookson Boats, Green Marine, and independent naval architects who had previously worked on Extreme Sailing Series platforms.

The AC45 entered competition in series promoted by entities like the America's Cup World Series and events organized around ports including San Francisco, Auckland, Portsmouth, and Valencia. Syndicates used the class as a development tool for crew drills, wing trim protocols, and hydrofoil control procedures that later influenced America's Cup campaigns led by Emirates Team New Zealand and Oracle Team USA.

Performance and capabilities

With T-foil appendages and rigid wing sails, AC45s were capable of rapid acceleration and sustained high-speed foiling in conditions similar to those encountered in regattas hosted by Auckland, San Francisco Bay, and Genoa. Speeds frequently exceeded those of conventional keelboats from events like the Sydney Hobart Yacht Race when foiling conditions aligned with wind regimes studied by meteorological services used by teams such as Land Rover BAR and Team NZ development squads. Handling demanded coordination akin to operations aboard craft in Extreme Sailing Series fleets, with flight control, pitch damping, and sail trim all critical to avoid catastrophic pitchpoling incidents that had historical precedents in multihull racing involving syndicates like Groupama.

Crew work mirrored practices from Oracle Team USA and Emirates Team New Zealand programs: high-frequency communication between tactician, helmsman, trimmers, and foils operator, all while managing load-bearing systems from suppliers previously engaged by Luna Rossa Challenge and Artemis Racing.

Operational use and operators

Operators included professional syndicates established for the America's Cup World Series such as Oracle Team USA, Emirates Team New Zealand, Luna Rossa Challenge, Artemis Racing, Team France, and several independent entries from nations represented at the 2013 America's Cup and 2017 America's Cup cycles. The class facilitated training, promotional events, and grassroots exposure through partnership with venues like Cowes and Marseille, and through media collaborations involving broadcasters who covered regattas in cities such as Newport and Portsmouth.

National sailing federations and professional teams used AC45s to refine foil handling and aerodynamic theories relevant to campaigns by entities like SoftBank Team Japan and Ben Ainslie Racing.

Variants and modifications

Several teams retrofitted AC45 hulls with upgrade packages that borrowed elements seen on experimental foiling craft from builders tied to Alinghi Red Bull Racing and Groupama Team France. Modifications included reinforced crossbeams, updated control pedal systems inspired by designs used in Oracle Team USA trials, and alternate foil profiles reflecting research from naval engineering groups affiliated with University of Auckland and European institutions engaged in America's Cup technology research. Some hulls served as testbeds for wing-sail articulations that later appeared on larger America's Cup challenger boats.

Incidents and safety

High-speed foiling introduced risks consistent with earlier multihull incidents experienced by syndicates like Artemis Racing during test programs and during competitive campaigns in venues such as San Francisco Bay and Auckland Harbour. Reported incidents ranged from structural failures under extreme load to capsize and collision events during inshore match races, prompting rule changes and safety protocols endorsed by the America's Cup Event Authority and implemented by teams including Oracle Team USA and Emirates Team New Zealand. Emergency recovery procedures and crew training were adapted from practices used in offshore teams such as those in the Volvo Ocean Race.

Legacy and impact on maritime racing

The AC45 class accelerated adoption of hydrofoil technology across professional sailing, influencing design choices in subsequent America's Cup cycles contested by Emirates Team New Zealand and Oracle Team USA and inspiring innovations in spectator-friendly regattas like the Extreme Sailing Series and new professional circuits. Its role in standardizing high-performance foiling platforms influenced training programs at institutions such as the Royal New Zealand Yacht Squadron and commercial initiatives by yards formerly engaged with Cookson Boats. The class contributed to broader public interest in cutting-edge multihull design and advanced sail aerodynamics, leaving a technological and cultural legacy within competitive sailing communities and among organizations that continue to develop foiling craft.

Category:Racing multihulls