9 Metre

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9 MetreDevelopment

Design| Development class
Hull
LOA| 18 m (59 ft)
Former Olympic class

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The International Nine Metre Class is a construction class, meaning that the boats are not identical but are all designed to meet specific measurement formula, in this case International Rule. At their heyday, Metre Classes were the most important group of international yacht racing classes, and they are still actively raced around the world. "Nine" in the class name does not, somewhat confusingly, refer to the length of the boat, but the product of the formula; 9mR boats are, on average, 18 meters long.

## History

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The 9mR was used as an Olympic Class during the 1920 Olympics. No entries were made. The International Rule was set up in 1907 to replace an earlier, simpler handicap system which was often local or at best, national, and often also fairly simple, producing extreme boats which were fast but lightly constructed and impractical. The rule changed several times in history, and only about 50 boats were ever built.

## Rule development

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### 1907 Rule

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Used from 1907–1920

9.000  metres = L + B + 1 / 3 G + 3 d + 1 / 3 S − F 2 {\displaystyle 9.000{\mbox{ metres}}={\frac {L+B+1/3G+3d+1/3{\sqrt {S}}-F}{2}}}

where

* L {\displaystyle L} = waterline length (LWL)
* B {\displaystyle B} = beam
* G {\displaystyle G} = chain girth
* d {\displaystyle d} = difference between girth and chain
* S {\displaystyle S} = sail area
* F {\displaystyle F} = freeboard

## Olympic results

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### 1920

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No competitors entered the Olympics in the 9 Metre.

## References

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* v
* t
* e

Olympic sailing classes

Current classes|

* 470
* 49er
* 49erFX
* Finn
* Formula Kite
* IQFoil
* Laser
* Laser Radial
* Nacra 17

Former classes
(In order of first use)|

* Ton classes (0–½, ½–1, 1–2, 2–3, 3–10, 10–20, 20+ & Open)
* 6 Metre
* 7 Metre
* 8 Metre
* 12 Metre
* 10 Metre
* 12 foot dinghy
* 18 foot dinghy
* 6.5 Metre
* 8.5 Metre
* 9 Metre
* 15 Metre
* Skerry cruiser 30 m2
* Skerry cruiser 40 m2
* French National Monotype 1924
* Snowbird
* Star
* O-Jolle
* Firefly
* Swallow
* Dragon
* 5.5 Metre
* 12 m2 Sharpie
* Flying Dutchman
* Tempest
* Soling
* Tornado
* Windglider
* Division II
* Lechner A-390
* Europe
* Mistral One Design
* Yngling
* RS:X
* Elliott 6m

Youth classes|

* Nacra 15
* Techno 293

Former youth classes|

* Byte

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