What is the AC45 foiling catamaran raced in the Louis Vuitton America's Cup World Series and how is it sailed? We find out

The boat being raced in the Louis Vuitton America’s Cup World Series is the AC45 – sometimes also called the AC45f. It is a one-design 44ft foiling catamaran (that’s what the ‘f’ in AC45 stands for).

The design was developed after the 72ft AC72 design that was raced for the 34th America’s Cup in San Francisco in 2013 and conceived as a scaled back, less expensive and more easily transportable version.

Once up on foils, these boats are very fast, reaching peak speeds of 37-38 knots.

They have two large L-foils and two spade rudders with T-foils.

They are crewed by five people: a helmsman, wing trimmer, floater, jib/gennaker trimmer and bowman. There is also space behind the aft beam for a guest racer/observer.

Oracle Team USA AC45

Oracle Team USA AC45


The floater is called different things on different teams. On Land Rover BAR, the floater is Freddie Carr and the nature of this job makes it one one the fastest paced and most energetic on board.

This crew runs around the boat and does different jobs, including controlling the running backstays. They are often operating at max heart rate.

The helmsman and wing trimmer sit next to each other and feedback to one another constantly throughout the racing. The tactician on board may be the wing trimmer or another crew. On Land Rover BAR, the tactician, usually Giles Scott, is the headsail trimmer.

The two foils have winglets that produce vertical lift, with rake controlled by elevators, while the T-foils on the rudders control horizontal stability.

The AC45 race boats can only be sailed as part of the World Series and practice days, so America’s Cup teams have their own training boats on which to try different control systems, perfect manoeuvres and make technical developments.

To race in the America’s Cup teams must take part in the eight events that make up the Louis Vuitton World Series events. They AC45 costs costs €675,000.

Hull construction: Carbon composite

LOA: 13.45 m (44.1 ft)

Beam: 6.90 m (22.6 ft)

Weight: 1,290–1,320 kg (2,840–2,910 lb)

Maximum draught : 2.7 m (8 ft 10 in)

Air draught : 21.5 m (71 ft) without extension, 25.5 m (84 ft) with extension

Wing: 20 m (66 ft) 83.5 m2 (899 sq ft) wing element with three slotted flaps.

It also includes a 4m wing extension: 4 m (13 ft)


Jib: 48 m2 (520 sq ft),

Gennaker area: 125 m2 (1,350 sq ft).

Matthew Sheahan sailed on the AC45 at last year’s Bermuda World Series events and explains his impressions of these super-powerful boats.