查看“︁12米”︁的源代码

[[File:Freedom1.jpg|thumb|{{le|自由號 (帆船)|Freedom (yacht)|自由號}}12米級帆船]]
'''12米'''（{{lang-en|12 Metre}}）是根據{{le|國際規例 (帆船)|International rule (sailing)|國際規例}}所設計的一個級別的[[帆船]]。此規格並不代表帆船任何一個尺寸為12米，而是根據特定的方程式所計算出來的總數不大於12米。它容許參賽者很大的靈活性對船隻的各範圍進行探索，亦帶來某程度上的規範確保比賽的公平性。首條方程式於1907年定立，並於1908、12及20年的[[奧林匹克運動會]]中使用。

1907年至20年的方程式：
:<math>
\frac{L + B + G/3 +3d + \sqrt{S}/3 - F}{2} \leq 12 \mbox{ metres}
</math>

1920至33年的方程式：
:<math>
\frac{L + G/4 +2d + \sqrt{S} - F}{2.5} \leq 12 \mbox{ metres}
</math>

1933年以後的方程式<ref>{{cite web|url=https://12mrclass.com/wp-content/uploads/2019/12/12M-Class-Rule-2018-WS-ApprovedforPublication.pdf|title=International Twelve Metre Class Rule|publisher=World Sailing / International 12-Metre Association|date=1 November 2018|access-date=2020-01-20|archive-date=2022-11-28|archive-url=https://web.archive.org/web/20221128035623/https://12mrclass.com/wp-content/uploads/2019/12/12M-Class-Rule-2018-WS-ApprovedforPublication.pdf|dead-url=no}}</ref>：
:<math>
\frac{L + 2d + \sqrt{S} - F}{2.37} \leq 12 \mbox{ metres}
</math>

* <math>L</math> = [[水线长]] (LWL)
* <math>B</math> = [[船宽]]
* <math>G</math> = {{le|链条周长|chain girth}}
* <math>d</math> = {{le|船壳周长|skin girth}}與链条周长的差距
* <math>S</math> = [[船帆]]面積
* <math>F</math> = [[乾舷]]

== 參考 ==
{{reflist}}

== 外部連結 ==
{{commons category}}
*[http://www.12mrclass.com/yachts/detail/273-itemId.511706987.html 12 Metre Specifications and Year] {{Webarchive|url=https://web.archive.org/web/20170703093439/http://www.12mrclass.com/yachts/detail/273-itemId.511706987.html |date=2017-07-03 }}
*[http://www.12mrclass.com The International Twelve Metre Association (ITMA)] {{Wayback|url=http://www.12mrclass.com/ |date=20221130070520 }}
*[http://www.12mr.de Trivia 12 Metre Restoration: 12 Metre yachts built the world wide] {{Wayback|url=http://www.12mr.de/ |date=20220815042508 }}
*[https://web.archive.org/web/20110902203759/http://www.12metercharters.com/history.asp History of 12 Metre Class and list of all US 12 Metre yachts built]
*[https://web.archive.org/web/20080908115319/http://www.sparkmanstephens.com/yachtdesign/sailyachts/twelvemeter_designs.php Sparkman & Stephens: The Twelves] (Technical explanation)
*{{cite book|title=The Twelve Metre Class|author=Luigi Lang, Dyer Jones & Jan Slee|publisher=ltyachting.com|year=2010|isbn=978-88-95171-22-7}}
*https://archive.today/20121208213332/http://www.columbiatrading.com/cgi-bin/columbia/30590.html
*[http://www.sceptre1958.co.uk ''Sceptre'' Preservation Society] {{Wayback|url=http://www.sceptre1958.co.uk/ |date=20220926070433 }}
* http://www.12mr.de/ {{Wayback|url=http://www.12mr.de/ |date=20220815042508 }} Trivia (Norsaga)

[[Category:奧林匹克運動會帆船比賽]]
[[Category:帆船賽事]]