Universal rule

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The Universal Rule (Universal Rule for Yachts) determined a

Before 1914, the

Mathematically, the Universal Rule formula as introduced in 1903 was: ${\displaystyle R={\frac {0.2\cdot L\cdot {\sqrt {S}}}{\sqrt[{3}]{D}}}}$[5]

Variables:

• L - Rated Boat length, definition tweaked from year to year by the New York Yacht Club
• S - Measured Sail area, up to 1923 to British Navy method, then amended for 3/4 mast-height jibstay and foresails, after the 1928 IYRU London Conference same as Metre-boats of the International Rule. See J-Class.
• D - Dead-weight by weighing, no sails no provisions, converted by formula to the equivalent cubic feet of seawater.
• R - Rating

The numerator contains a yacht's speed-giving elements, length and sail area, while the retarding quantity of displacement is in the denominator. Also the result will be dimensionally correct; R will be a linear unit of length (such as feet or meters). Sailing craft are thus rated when their ${\displaystyle R}$ rating falls within a certain range. J-Class boats, for example, are any single masted craft with an ${\displaystyle R}$ between 65 and 76 feet (adjusted upward from original to allow British yachts under the International Rule to compete.

The listing for single mast boats, namely classes I through S.

• Class I: Rating = 76– 88 feetSkene, 1941, indicates this applicable to yachts from around 1930:

Universal Rule: ${\displaystyle {\textbf {Rating}}={\frac {0.182\cdot {\textbf {L}}\cdot {\sqrt {SailArea}}}{\sqrt[{3}]{Displacement}}}}$

where

• ${\displaystyle {\textbf {L}}=L.W.L.+.5(q.b.l.-{\frac {100-{\sqrt {L.W.L.}}}{100}}\cdot L.W.L.)}$
• L.W.L. = Length (on) Waterline, measured in measurement trim, in upright position^[6][7]
• q.b.l. = quarter-beam length, measured at the quarter-beam position of the maximum beam (mainframe)on the inside of the hull to the inside of the hull skin
• The Length factor in the 1903 Formula is the Measurement Length^[8]

The yachts were divided into Development Classes

• Class J
  : Rating = 65 – 76 feet
• Class K: Rating = 55 – 65 feet
• Class L: Rating = 46 – 55 feet
• Class M: Rating = 38 – 46 feet
• Class N: Rating = 31 – 38 feet
• Class P: Rating = 25 – 31 feet
• Class Q: Rating = 20 – 25 feet
• Class R: Rating = 17– 20 feet
• Class S: Rating = 0 – 17 feet

Incorrect upper limits; should read 16.x feet, etc.^[9]

• The Pond Racing Yacht Marble-head is related to the Universal Rule^[10]
• The current International A class yacht retains several elements of the Universal Rule in its formulas^[11]

There were multi-mast classes too, running Class A to Class H.

See also

• Square Metre Rule (sailing)
• Ton class
• International or 'Metre' Rule

Footnotes

Note: The 1941 edition of Norman Skene's book (posthumously (1878-1932)) is the most up to date outside the confidential notes of the Rules Commission notes of the New York Yacht Club. Skene was the designer of J-Class yacht "Yankee" (1930)^{[citation needed]}, America's Cup contender, eliminated in the last selection match,^[12] so had access to these rules.

• "New York Yacht Club", website www.nyyc.org and New_York_Yacht_Club
• "The M-yacht", website extant?
• "J-Class Racing Association", J Class Yachts Association, website www.jclassyachts.com/news
• "J Class - Sparkman & Stephens" www.sparkmanstephens.com/yachtdesign/sailyachts/jclass_designs.php
• "America's Cup Book 1851-1983', John Rousmaniere
• "The Herreshoff Marine Museum", website www.herreshoff.org/ and Herreshoff_Marine_Museum
• "Twelve Meter Challenges for the America's Cup", Norris D. Hoyt, 1977
• "The Guinness Book of Yachting Facts and Feats", Peter Johnson (editor), 1975
• "Sensible Cruising designs",L. Frances Herreshoff, 1991 (contains lines of two J-class yachts)
• "Mystic Seaport Museum" www.mysticseaport.org/ and Mystic_Seaport
• Several articles by "Wooden Boat" magazine on S, R, Q, P, M and J Classes. WoodenBoat Magazine www.woodenboat.com
• "The Twelve Metre Yacht: Its Evolution and Design 1906-1987",Chris Freer
• "The America's Cup: The History of Sailing's Greatest Competition in the Twentieth Century" by Dennis Conner (Author), Michael Levitt (Author), 1992
• " Olin J. Stephens II. Lines: A half-century of Yacht Designs by Sparkman & Stephens, 1930-1980.", 2002, David R. Godine,
  ISBN 978-1-56792-195-3
  .
• "Vim" a Twelve Meter Design by Sparkman and Stephens
• "Aero-hydrodynamics of sailing", Czesław Antony Marchaj,
  ISBN 0-229-98652-8
• "1928 IYRU London Conference"[13]
• "Biography Norman l Skene by John G Evans", Sciences 360 www.sciences360.com

References