The AC72 (America's Cup 72 class) is a class of wingsailcatamarans built to a box rule, which governs the construction and operation of yachts competing in the 2013 Louis Vuitton and the America's Cup races. The class was subsequently replaced by the smaller AC50 class.
Background
Following the 2010 America's Cup, where the Golden Gate Yacht Club's USA 17trimaran defeated the catamaran Alinghi 5, it was decided by the winners that the next America's Cup competition would be sailed in catamarans in the hope of making the sport more attractive to television audiences.[2] At the same time a smaller sister class, the AC45, was developed to allow teams to practice and adjust to the new formula as well as create a greater exposure of sailing to the general public with the America's Cup World Series.
Specifications
The AC72 has the following maximum specifications:[3]
Overall length: 26.2 metres (86 ft)
Waterline length: 22.0 metres (72.2 ft)
Beam: 14.0 metres (45.9 ft)
Weight: 5,900 kilograms (13,000 lb)
Maximum draught: 4.4 metres (14 ft)
Crew: 11
Maximum speed
Using foils for the first time in the America's Cup the AC72 was expected to sail faster than the wind: upwind at 1.2 times the speed of the true wind, and downwind at 1.6 times the speed of the true wind.[4][5] But in fact it proved faster, averaging about 1.8 times the speed of the wind with peaks slightly over 2.3.[6] A multiple of 2.79 times wind speed was achieved by Emirates Team New Zealand in practice, which sailed at 44.15 knots (81 km/h, 50 mph) in 15.8 knots of wind on July 18, 2013.[7]
Typical racing speeds are over 30 knots (55 km/h, 34 mph) with the boats capable of sailing well over 40 knots (74 km/h, 46 mph) in the right conditions. The fastest race speed recorded was on Emirates Team New Zealand which was 47.57 knots (88 km/h, 55 mph) in 21.8 knots of wind (2.2 times the wind speed) on September 24, 2013.[8]
On 17 October 2012, Oracle Racing's AC72 pitchpoled (somersaulted) and capsized, causing severe damage to the yacht. The wingsail was completely destroyed while being swept under the Golden Gate Bridge by a strong ebb tide.[12]
The other two teams, Luna Rossa Challenge, and Team New Zealand, both suffered minor setbacks, including hitting seals[13] and damaging their wing sails, resulting in loss of sailing time.[14]