12 Metre
Rating class for racing sailboats, used in America's Cup 1958–1987.
The 12 Metre class is a rating class for racing sailboats designed to the International rule, enabling fair competition between boats that rate in the class while retaining design freedom. The designation "12 Metre" does not refer to any single measurement but rather the sum of components directed by a formula governing design and construction parameters. First built in 1907, the class was used in the Olympic Games of 1908, 1912, and 1920, and is best known as the boat design used in the America's Cup from 1958 to 1987.
- First built
- 1907
- Olympic use
- 1908, 1912, 1920
- America's Cup use
- 1958 to 1987
- Typical length overall
- 65 to 75 feet (about 20 to 23 m)
- Typical mast height
- roughly 85 feet (26 m)
- Rig type
- most often sloop-rigged
Lore & Background
The 12 Metre class was established in 1907 under the International rule, with the first boats built that year. The class saw limited participation in the Olympic Games of 1908, 1912, and 1920. Its most prominent role came when the America's Cup resumed in 1958 after World War II, as more economical vessels were desired to replace the huge J-class yachts. The class was used in the America's Cup until 1987, when it was replaced by International America's Cup Class boats for the 1992 competition.
The formula governing the class has been modified several times, with four distinct periods: the first rating rule (1907–1920), second rating rule (1920–1933), third rating rule (from 1933 onwards, also used for the America's Cup from 1956), and later adjustments. The formula includes weighted measurements such as waterline length, sail area, girth, and freeboard, and the sum must be less than or equal to 12 metres. Designers are free to change variables like rudder and keel size as long as the boat remains seaworthy and safe.
Notable boats include Sceptre, launched in 1958 for the UK challenge, which lost to Columbia. Alexander Robertson and Sons Ltd built two early 12-Metres: Heatherbell (1907) and Cyra (1909). Several new 12 Metres have been built after 1987, including 'Kiwi Magic' (1992) and 'Lionheart' (2019), and a revival of interest in classic yachts has led to increased restorations and racing of older boats.
Reader's Guide
The 12 Metre class holds significance as a design rule that balanced competition with creativity, allowing designers to experiment within a strict formula. Its use in the America's Cup from 1958 to 1987 made it the most famous racing yacht class of that era, replacing the expensive J-class and enabling more economical competition. The class's formula evolved over time, incorporating advances in materials, design technology, and equipment, while maintaining safety and competitive parity. The class's legacy includes a revival of interest in classic yachts, with many older boats restored and raced in prestigious regattas. The 12 Metre class demonstrates how a rating rule can foster innovation while ensuring fair racing, influencing later yacht design and competition formats.
Did You Know?
- The designation '12 Metre' does not refer to any single measurement on the boat, but rather the sum of components directed by the formula.
- The 12 Metre class was used in the Olympic Games of 1908, 1912, and 1920, though few boats participated.
- The class was used in the America's Cup from 1958 to 1987, after which it was replaced by International America's Cup Class boats.
- Several new 12 Metre boats have been built after 1987, including 'Kiwi Magic' (1992) and 'Lionheart' (2019), and a revival of interest in classic yachts has led to restorations.
Frequently Asked Questions
What does the name '12 Metre' actually refer to?
Despite the name, no single dimension of the boat is twelve metres. The figure comes from a rating formula that sums various design and construction parameters, and a boat qualifies for the class when its calculated rating reaches that threshold.
Was the 12 Metre an Olympic class?
Yes, it appeared at three consecutive Summer Games: 1908 in London, 1912 in Stockholm, and 1920 in Antwerp. It has not been part of the Olympic programme since 1920.
What is the 12 Metre best known for?
The class is most closely associated with the America's Cup, where it served as the designated racing class from 1958 through 1987. During that span it became the iconic symbol of the trophy competition.
How large is a typical 12 Metre?
Most boats in the class measure between 65 and 75 feet (roughly 20–23 m) overall, with masts reaching about 85 feet (26 m) above the deck. The majority are sloop-rigged, though the class allows some rig variation.
Is the 12 Metre a single fixed design?
No—it is a rating class rather than a one-design rule, so builders enjoy considerable freedom in hull shape, rig, and construction. The only requirement is that the finished boat's calculated rating under the International rule places it within the 12 Metre band.
More in Olympic sailing classes 1-24
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