12-metre Class
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The 12 Metre class is a rating class for racing sailboats that are designed to the International rule. It enables fair competition between boats that rate in the class whilst retaining the freedom to experiment with the details of their designs. The designation "12 Metre" does not refer to any single measurement on the boat, and is not referencing the vessels overall length, rather, measures the sum of the components directed by the formula which governs design and construction parameters. Typically 12 Metre class boats range from 65 to 75 feet (about 20 to 23 m) in length overall; they are most often
sloop A sloop is a sailboat with a single mast typically having only one headsail in front of the mast and one mainsail aft of (behind) the mast. Such an arrangement is called a fore-and-aft rig, and can be rigged as a Bermuda rig with triangular sa ...
-rigged, with masts roughly 85 feet (26 m) tall. The first 12 Metres were built in 1907. The 12 Metre class was used in the Olympic Games of 1908,
1912 Events January * January 1 – The Republic of China (1912–49), Republic of China is established. * January 5 – The Prague Conference (6th All-Russian Conference of the Russian Social Democratic Labour Party) opens. * January 6 ...
and 1920 but few boats participated in these events. The 12 Metre class boats are best known as the boat design used in the
America's Cup The America's Cup, informally known as the Auld Mug, is a trophy awarded in the sport of sailing. It is the oldest international competition still operating in any sport. America's Cup match races are held between two sailing yachts: one f ...
from 1958 to 1987. Competitiveness between boats in the class is maintained by requiring the boats to be in compliance with the 12 Metre formula. Designers and builders are required to take into account such things as the
sail A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may ...
area, the boat length at the
waterline The waterline is the line where the hull of a ship meets the surface of the water. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line (positioned amidships), that indi ...
and the boat girth (the measurement around the boat from one sideboard, under the
keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...
, and then over the top on the opposite side back to the original side). The measurements are then weighted in the formula. For example, the present formula takes the square root of the sail area rather than total area. The combination of weighted measurements must be less than or equal to 12 metres. Designers are free to change any of the component variables, as well as other details, such as the size of the
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...
and keel, so long as the corresponding changes elsewhere produce an ultimate sum of 12 metres and the resulting boat is both seaworthy and safe. Though disparity between boats are minimized by the rule, enough variation exists so that races are as much about design and construction as they are about seamanship and tactics.


History


The formula and rules

The Formula and associated rules for designing and constructing 12 Metre yachts has been modified several times from inception in racing. The purpose of the Formula and rules was to encourage designer's creativity to optimize designs to get the best overall performance when racing while still maintaining competitive racing postures between different designs. Although the Formula and Rules allowed for some creativity they were also intended to be comprehensive enough to eliminate loop holes which could result in an extreme design which conformed to the 12 Metre rule but completely outclassed other contemporary designs on the race course. If the rules were considered to be too loose then it would discourage the building of new 12 Metre yachts for fear of a new boat being outclassed even before it was launched. The Rules were typically updated in response to advances in areas such as material technology (e.g. metal masts versus wooden masts), design technology (e.g. use of the wind tunnel to design sails and sail/mast combinations, advances in fluid dynamics), and equipment (e.g. winch technology). The Rule has four distinct periods:


First rating rule

Used from 1907 to 1920 : \frac \leq 12 \mbox where * L =
waterline length A vessel's length at the waterline (abbreviated to L.W.L)Note: originally Load Waterline Length is the length of a ship or boat at the level where it sits in the water (the ''waterline''). The LWL will be shorter than the length of the boat over ...
(LWL) * B =
beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized grou ...
* G =
chain girth Chain girth is a measurement of a yacht hull. Chain girth is specified in some design rules to handicap or match the capabilities of sailing vessels of similar design such as the 12 metre boats. Chain girth is measured as a straight line from ...
* d = difference between
skin girth {{unreferenced, date=January 2018 Skin girth is a measurement of a yacht hull. Skin girth is specified in some design rules to handicap or match the capabilities of sailing vessels of similar design such as the 12 metre The 12 Metre class is ...
and chain girth * S =
sail area A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may ...
* F =
freeboard In sailing and boating, a vessel's freeboard is the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship. In commercial vessels, the latter criterion measured relativ ...


Second rating rule

Used from 1920 to 1933. : \frac \leq 12 \mbox where * L = waterline length (LWL) * G = chain girth * d = difference between skin girth and chain girth * S = sail area * F = freeboard


Third rating rule, and, from 1956, the America's Cup rule

Used from 1933 onwards: : \frac \leq 12 \mbox where * L = waterline length (LWL) * d = difference between skin girth and chain girth * S = sail area * F = freeboard Associated with the formula is an extremely comprehensive set of rules, which can be classified into two main areas: safety, and ensuring competitive racing. For example, the maximum total area of all cockpits is specified to minimise the chance of a boat being swamped in rougher seas. Structural requirements are specified to ensure that strength is not sacrificed by the need to get weight low down in the keel. Materials are specified plus numerous other details concerning all aspects of the boat. The intention is to challenge designers but ensure competitive racing.


America's Cup

The America's Cup racing resumed in 1958 after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
by a syndicate led by
Henry Sears Henry Sears (1913 – March 1982) was an American commander and a commodore of the New York Yacht Club who competed in the America's Cup and discovered multiple species of marine fish. Early life Sears began sailing at the age of eight. As a ...
, more economical vessels were desired to replace the huge and expensive
J-class yacht A J-Class yacht (sometimes called a "J-boat") is a single-masted racing yacht built to the specifications of Nathanael Herreshoff's Universal Rule. The J-Class are considered the peak racers of the era when the Universal Rule determined eligibi ...
s that were raced in the 1930s; the 12 Metre class was selected. In September 1956, a
Royal Yacht Squadron The Royal Yacht Squadron (RYS) is a British yacht club. Its clubhouse is Cowes Castle on the Isle of Wight in the United Kingdom. Member yachts are given the suffix RYS to their names, and are permitted (with the appropriate warrant) to we ...
syndicate was formed to build a 12 Metre for the 1958
America's Cup The America's Cup, informally known as the Auld Mug, is a trophy awarded in the sport of sailing. It is the oldest international competition still operating in any sport. America's Cup match races are held between two sailing yachts: one f ...
. The UK challenger was selected based on model tank testing and David Boyd's second design was chosen. ''
Sceptre A sceptre is a staff or wand held in the hand by a ruling monarch as an item of royal or imperial insignia. Figuratively, it means royal or imperial authority or sovereignty. Antiquity Ancient Egypt and Mesopotamia The ''Was'' and other ...
'' was launched at the yard of
Alexander Robertson & Sons Alexander Robertson & Sons was a boatyard in Sandbank, Argyll, Sandbank, Argyll and Bute, Scotland, from 1876 to 1980. The yard was located on the shore of the Holy Loch, not far from the Royal Clyde Yacht Club (RCYC) at Hunters Quay, in the bui ...
on 2 April 1958, but lost to the New York Yacht Club yacht ''Columbia'' in September 1958. ''Sceptre'' is currently owned and raced by the Sceptre Preservation Society. Alexander Robertson and Sons Ltd also built two of the earliest 12-Metres: ''Heatherbell'' (designer Thomas Glen-Coats, 1907), which represented Finland in the 1912 Summer Olympics; ''Cyra'' (designer
Alfred Mylne Alfred Mylne (1872–1951) was a Scottish yacht designer, born in Glasgow. He founded A Mylne & Co. in 1896. Work Alfred Mylne was apprenticed to the Scottish shipbuilders Napier, Shanks and Bell, and went on to work as a draftsman and appr ...
, 1909). In 1987, use of the 12 Metre class was ended, switching to
International America's Cup Class The International Americas Cup Class is a class of racing yacht that was developed for the America's Cup between 1992 and 2007. These yachts, while not identical, were all designed to the same formula to offer designers the freedom to experiment ...
boats for the 1992 competition.


Post-America's Cup

12 Metre yachts were used for the last time in America's Cup competition at the 1987 event held in Fremantle, Australia. 12 Metres continued to race together on a local basis but due to the high cost and without the impetus and prestige surrounding competition in the America's Cup, no new boats have been built since 1987 save one. The latter part of the 20th century saw a big revival in interest in classic yachts including 12 Metre yachts and particularly those of wooden construction. There was an increasing number of prestigious regattas in attractive locations such as the Mediterranean and the Caribbean. Also, a more prosperous global economy prevailed and the result was an increasing number of restorations and racing of older 'classic' 12 Metres. Potential restorers of older boats who wanted to race were potentially faced with a dilemma of whether to restore a boat to its original specification or make modifications to make an older design competitive with a newer design. For example, a yacht designed under the First International Rule would have a wooden mast,
gaff rig Gaff rig is a sailing rig (configuration of sails, mast and stays) in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar (pole) called the ''gaff''. Because of the size and shap ...
, and sails made of cotton; whereas yachts designed under the Third International Rule, such as ''Vim'', had a metal mast,
Bermuda rig A Bermuda rig, Bermudian rig, or Marconi rig is a configuration of Mast (sailing), mast and rigging for a type of sailboat and is the typical configuration for most modern sailboats. This configuration was developed in Bermuda in the 1600s; the t ...
, and sails made from
Dacron Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...
. To encourage participation in racing and also engage the restoration process which remained true to the spirit of the original design, the 12 Metre class association introduced a handicapping system to allow 12 Metres of all ages to race together on a more equal footing. The basis is a handicap applied to each boat according to the 'era' of its design to encourage owners to restore older boats and participate in exciting and sociable racing. A 12 Metre is classified as belonging to one of three periods. Each Period is defined as a range of dates which coincided with a particular type of keel or rudder design becoming widespread. *Division A:- Also called Grand Prix, this subclass starts when winged keels became the norm. It covers all 12 Metre yachts built with winged keels and all constructed after 1983. ''
Australia II ''Australia II'' (KA 6) is an Australian 12-metre-class America's Cup challenge racing yacht that was launched in 1982 and won the 1983 America's Cup for the Royal Perth Yacht Club. Skippered by John Bertrand, she was the first successful ...
'', launched in 1982, was the first wing keeled 12 Metre so is considered the first of this division. ''USA'' (US 61), also fits into this category, even though its keel structure is different from the standard winged keel of the class. It is also the only 12 Metre to have a "canard" or rudder mounted forward of the keel. *Division B (Modern):- Starts when a
skeg A skeg (or skegg or skag) is a sternward extension of the keel of boats and ships which have a rudder mounted on the centre line. The term also applies to the lowest point on an outboard motor or the outdrive of an inboard/outboard."A small fin f ...
mounted rudder separated from the keel became the norm. It includes all 12 Metres built during the period 1968 - 1983. '' Intrepid'' is considered the first Modern even though it was built in 1967 since it was the first 12 Metre to use a skeg mounted rudder. It excludes ''
Australia II ''Australia II'' (KA 6) is an Australian 12-metre-class America's Cup challenge racing yacht that was launched in 1982 and won the 1983 America's Cup for the Royal Perth Yacht Club. Skippered by John Bertrand, she was the first successful ...
'', built in 1982, which is in Period A due to its winged keel design. *Division C (Classic):- All other 12 Metre class yachts built before 1968 but excluding '' Intrepid'' which is in Period B by virtue of its skeg mounted rudder design. Divisions D (Vintage) & E (Antique) are the remaining 2 Divisions based on the year of construction including Antique (most of which are in fact gaff rigged). Older sloop-rigged yachts like ''Vim'' and ''Onawa'' fit into the Vintage category, yachts like ''
Erna Signe ''Erna Signe'' is a 1911 Swedish 12 metre class yacht. It was by designed by William Fife III and built by August Plym at Neglingevarvet. Career ''Erna Signe'' was launched in June 1911. ''Erna Signe'' competed in the 1912 Summer Olympics, hel ...
'' belong to the Antique division. In the early 21st century interest in ownership and restoration of 12 Metres was such that specialist restoration companies would speculatively locate old boats under threat of destruction and publicize the availability in order to attract the funding for a full restoration.


Events


Olympics


World Championships


Yachts

* ''Onawa'' (US 6) & ''Anitra'' (US 5) - The oldest American 12 Metre yachts still intact. * '' Vim'': Designed in 1939 by
Olin Stephens Olin James Stephens II (April 13, 1908 – September 13, 2008) was an American yacht designer. Stephens was born in New York City, but spent his summers with his brother Rod, learning to sail on the New England coast. He also attended the Massa ...
who considered the possibilities given by every aspect of the rules and produced a very fast boat. ''Vim'' had numerous innovative features including a trim tab on the rudder, two-speed winches and a lighter mast made of
Duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...
(a form of aluminium used in the aircraft industry). ''Vim'' is considered a benchmark design which was continually refined over her racing career. In 1939 ''Vim'' came to the UK and won 19 races out of 28. The next generations of 12 Metres designed and built 20 years after ''Vim'' was launched still found Vim extremely difficult to beat in competition. * Sparkman & Stephens designed five successful America's Cup defenders for the NYYC. The first was ''Columbia'', winner of the 1958 Cup, followed by ''Constellation'' in 1964. ''Intrepid'' won the 1967 and 1970 America's Cups. '' Courageous'' won in 1974 and 1977 (skippered by Ted Hood in 1974 and
Ted Turner Robert Edward "Ted" Turner III (born November 19, 1938) is an American entrepreneur, television producer, media proprietor, and philanthropist. He founded the Cable News Network (CNN), the first 24-hour United States cable news, cable news ch ...
in 1977). The last of the S&S designed 12s to win the America's Cup was ''Freedom'' in 1980. '' Columbia'' ''Intrepid'' ''Courageous'' and ''Freedom'' are still sailing and racing today in Newport. * ''Sceptre'' (K 17), the British challenger for the America's Cup in 1958, is believed to be the only UK challenger still sailing in British waters. *''Weatherly'', designed by
Philip Rhodes Philip Leonard Rhodes (1895–1974) was an Americans, American naval architect known for his diverse yacht designs. Life Rhodes designed a wide variety of vessels from 7' dinghies to 123' motor-sailors, from hydrofoil racers to America's Cup win ...
, successfully defended the
America's Cup The America's Cup, informally known as the Auld Mug, is a trophy awarded in the sport of sailing. It is the oldest international competition still operating in any sport. America's Cup match races are held between two sailing yachts: one f ...
in 1962, and is also sailing and racing today in Newport. * ''
Australia II ''Australia II'' (KA 6) is an Australian 12-metre-class America's Cup challenge racing yacht that was launched in 1982 and won the 1983 America's Cup for the Royal Perth Yacht Club. Skippered by John Bertrand, she was the first successful ...
'', Alan Bond's famous
winged keel The winged keel is a sailboat keel layout first fitted on the 12-metre class yacht ''Australia II'', 1983 America's Cup winner. Design This layout was adopted by Ben Lexcen, designer of ''Australia II''. Although Ben Lexcen "had tried the winged ...
boat that won the 1983 America's Cup. The boat that ended the longest winning streak in sport. Designed by
Ben Lexcen Benjamin Lexcen AM (born Robert Clyde Miller, 19 March 1936 – 1 May 1988) was an Australian yachtsman and marine architect. He is famous for the winged keel design applied to ''Australia II'' which, in 1983, became the first non-American ya ...
, ''Australia II'' was one of the first racing yachts to use appendages on the keel, which allowed the yacht to point higher, sail faster and be quicker in stays. The keel design also allowed a reduction in weight in the keel which then allowed other beneficial changes in the measured dimensions which resulted in a yacht optimized for the conditions on the race course at Newport, Rhode Island. * ''
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
'' (KZ 7) "Kiwi Magic" Runner-up in
1987 Louis Vuitton Cup The 2nd Louis Vuitton Cup was held in Fremantle, Western Australia in 1987. The winner, Stars & Stripes, went on to challenge for and win the 1987 America's Cup. Teams Twelve syndicates from six countries (Canada, France, Italy, New Zealand ...
, and the third 12 Metre to be made from fibreglass. Sister yachts KZ-3 and KZ-5 did not compete at the 1987 America's Cup but took part in the 1986 World Championships in Perth. KZ-7 went on to win the 1988 World Championship in Sardinia. Nicknamed the " Plastic Fantastic". Skippered by Chris Dickson * '' Stars & Stripes 87'' (US 55) Winner of the 1987 America's Cup. The fastest heavy weather 12 Metre boat ever built.


See also

* Square Metre Rule (sailing) *
Ton class Ton classes are categories used to identify classes of yachts. Thames tonnage Early attempts at creating rating rules were based on the British "old tonnage measurement" system to calculate the volume of the hold of large commercial ships. It ga ...


References


External links


12 Metre Specifications and Year

The International Twelve Metre Association (ITMA)Trivia 12 Metre Restoration: 12 Metre yachts built the world wideHistory of 12 Metre Class and list of all US 12 Metre yachts builtSparkman & Stephens: The Twelves
(Technical explanation) * *https://archive.today/20121208213332/http://www.columbiatrading.com/cgi-bin/columbia/30590.html
''Sceptre'' Preservation Society
* http://www.12mr.de/ Trivia (Norsaga) {{America'sCup Keelboats Olympic sailing classes 12-metre class Development sailing classes