Talk:Universal rule

The context here is Yachting is it not? Can we have a somewhat less "universal" title? --Wetman 21:20, 29 August 2005 (UTC)

Yep, it's a Yachting term, i'm not a yachter so I don't know a ton about the topic, just enough to build this stub :) I just know that is is really called the "Universal Rule" (double caps), if there are some other Universal Rules though perhaps this should be turned into a disambig page, but I couldn't readily locate any other Universal Rules on Wikipedia --Fxer 21:46, August 29, 2005 (UTC)

Overall or waterline length?

Is the Length factor the overall length or the waterline length? I'm guessing waterline but I don't know much about boats. Lisiate

I think this article is slightly inaccurate, definitely incomplete. Skene indicates this:

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

where

• ${\textbf {L}}=L.W.L.+.5(q.b.l.-{\frac {100-{\sqrt {L.W.L.}}}{100}}\cdot L.W.L.)$16:18, 16 June 2014 (UTC)
• L.W.L. = Load Water line Length
• q.b.l. = quarter-beam length

where for example the J-class yacht Rating must be equal to 76, where 76 ft ≤ L.W.L. < 88 ft and Displacement ≤ 166 tons

The NYT archives describes L as a practical model for the "sailing length", which is the waterline length when the boat is heeled in moderate winds. The article also offers the contemporary method for displacement measurement of boats, but you have to be knowledgeable about things like Simpson's rule, which I suspect must have been similar to the Cubical Contents Rule in use for the 1881 America's Cup.

Generally speaking, this was the situation as it stood after deliberation/proposal/vote in 1905. If nothing was changed for 1930 — 1937 America's Cup challenges, I suggest the article be permanently amended.

Nuttyrave (talk) 22:29, 9 May 2009 (UTC)

"Load Waterline rejected", New York Times, 1908-10-09 states that in 1908 the Universal Rule replaced the 5.5 factor in the divisor by 0.182 in the numerator. The article mentions other restrictions such as schooner/yawl handicaps when racing with sloops, as well as limitations on draught. As such, I have reverted the top formula to reflect the change. The article is still wrong and incomplete.Nuttyrave (talk) 12:33, 28 May 2009 (UTC)

Proposal ChangesAmericascupfreak (talk) 16:05, 16 June 2014 (UTC)

Extended content

The Universal Rule (Universal Rule for Yachts) determined a yacht's eligibility to race in the America's Cup from 1914 to 1937 and for this the J-class was chosen. Boats built according to the rule reached their peak in the large J-class yachts. This Rating Rule is intended to calculate a rating for yachts, which can then be used to calculate its Time Correction Factor (T.C.F.) in order to have disparate yachts racing against each other.

Before 1914, the Seawanhaka Rule was used for America's Cup racing, and after 1937 smaller boats were desirable, and so the International Rule gained popularity in the 12-Metre Class and smaller to the detriment of the M-class and smaller and became the standard. The 6, 8 and 12 Meter (Metre)16:05, 16 June 2014 (UTC) Classes and from 1948 on the 5.5-Meter (Metre)16:05, 16 June 2014 (UTC), were the most popular and the 12-Metre was used for the America's Cup until 1987, the last year the America's Cup was sailed in 12-meter yachts.

Yacht designer Nathanael Herreshoff devised the rule in 1902 "Herreshoff Rule" and accepted by the New York Yacht Club as the rule-making body for 1903. Herreshoff had designed winning America's Cup yachts which fully exploited the Seawanhaka rule, which was based only on a yacht's upright waterline length and sail area, to create narrow boats with long overhangs. This reached its peak with Reliance, the defender of the 1903 America's Cup, which was described as a "racing freak", suitable only for certain conditions. This prompted Herreshoff to propose a rule which also took into account the displacement of the boat.

Universal Rule formula

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

Variables:

• L - Rated Boat length, definition tweaked from time to time 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 $R$ rating falls within a certain range. J-Class boats, for example, are any single masted craft with an $R$ 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. Skene,1941, indicates this applicable to yachts from around 1930:16:05, 16 June 2014 (UTC)

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

where

• ${\textbf {L}}=L.W.L.+.5(q.b.l.-{\frac {100-{\sqrt {L.W.L.}}}{100}}\cdot L.W.L.)$
• L.W.L. = Length (on) Waterline, measured in measurement trim, in upright position
• 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

The yachts were divided into Development Classes

• Class I: Rating = 76– 88 feet16:05, 16 June 2014 (UTC)
• 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; as far as is known, none built
• Class P: Rating = 25 – 31 feet
• Class Q: Rating = 20 – 25 feet
• Class R: Rating = 17– 20 feet
• Class S: Rating = 0 – 17 feet

(Remove)16:05, 16 June 2014 (UTC)

• The Pond Racing Yacht Marble-head is related to the Universal Rule

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

Footnotes

Note The 1941 edition of Norman Skene's book (posthumously (1878-1932)) contained a brief description of the rule.16:05, 16 June 2014 (UTC) (Remove: 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), America's Cup contender, eliminated in the last selection match, so had access to these rules.)16:05, 16 June 2014 (UTC)

• "New York Yacht Club", website www.nyyc.org and en.wikipedia.org/wiki/New_York_Yacht_Club
• "The M-yacht", website
• "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 en.wikipedia.org/wiki/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 en.wikipedia.org/wiki/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 www.sparkmanstephens.com/yachtdesign/sailyachts/twelvemeter_designs...
• "Aero-hydrodynamics of sailing", Czesław Antony Marchaj, ISBN 0-229-98652-8e: en.wikipedia.org/wiki/Czesław_Marchaj
• "1928 IYRU London Conference"

References

"Biography Norman l Skene by John G Evans", Sciences 360 www.sciences360.com › Earth Science › Water and Oceanography ~

update references

can we find a better link/citation for "skene 1941" the hyperlink just goes back to the Wikipedia page. Rqds (talk) 03:58, 11 May 2025 (UTC)