The J-Class serves as a rating for large sailing yachts designed between 1930 and 1937. Reserved for a wealthy elite of yachtsmen, these boats were used to compete with the best sailing talents in three races of the America's Cup.

The 1930s

The J-Class is a development of Nathanael Herreshoff's Universal Rule for racing boats. It was established in 1929, two years after it was agreed between Britain and America that the Universal Rule would be used for large boats, where the International Rule would be used for 12mR boats and smaller. As a result, the 1930s America's Cup races were all fought in the J-Class.

Following Sir Thomas Lipton's near success in the 1920 America's Cup, he challenged again for the last time at age 79, in 1929. The challenge drew all the novelties developed in the previous decade on small boats to be ported onto large boats, and pitted British and American yacht design into a technological race. Between 1930 and 1937, the improvements brought to the design of sailboats were numerous and significant:

• the high-aspect bermuda rig replaces the gaff rig on large sailboats (1930)
• solid-rod lenticular rigging for shrouds and stays (1930)
• luff and foot grooved spars with rail and slides replace wooden hoops (1930)
• multiplication of spreader sets: one set previously (1914), two sets (1930), three sets (1934), four sets (1937)
• multiplication of the number of winches: 23 winches, Enterprise (1930)
• electronic navigational instruments borrowed from aeronautics with repeaters for windvane and anemometer, Whirlwind (1930)
• "Park Avenue" boom (Enterprise, 1930) and "North Circular" boom (Rainbow, 1934) developed to trim mainsail foot
• riveted aluminium mast (Duralumin), Enterprise (1930)
• Genoa Jib (Rainbow, 1934) and quadrangular jib (Endeavour, 1934)
• development of nylon parachute (symmetric) spinnakers, including the World's largest at on Endeavour II (1936)
• Duralumin wing-mast, Ranger (1937)

All these improvements would not have been possible without the context of the America's Cup. The competition was a bit unfair because the British challengers had to be constructed in the country of the Challenging Yacht Club (a criterion still in use today), and had to sail on their own hull to the venue of the America's Cup (a criterion no longer in use today): The design for such an undertaking required the challenging boat to be more sea-worthy than the American boats, whose design was purely for speed in closed waters' regattas. The yachts that remain in existence are all British, and probably log more nautical miles today than they ever did. This would not have been possible if Charles Ernest Nicholson did not obtain unlimited budgets to achieve the quality of build for these yachts. Yacht designer Clinton Hoadley Crane noted in his memoires that "America's Cup racing has never led to good sportsmanship. The attitude of the New York Yacht Club [...] has been more that of a man in the forward position at war who has been ordered to hold his position at all costs – 'at all costs.". In 1930, Thomas Lipton spent $1,000,000 for his Shamrock V challenge when America was facing a stock market crash, but the NYYC still built four cup defenders. The rivalry lead both countries to put a display of true technological demonstrators using the maximum load waterline length authorised by the rule for Endeavour II and Ranger in 1937. This seems to concur with J.P. Morgan's famous quote about yachts: "If you have to ask how much it costs, you cannot afford it."

Most J-Class yachts were scrapped prior or during World War II because steel and lead had become precious to the war effort. In the post-war era, J-Class racing was deemed far too expensive, so no challenge for the America's Cup was placed until 1958 with the smaller third International Rule 12mR class. A revival of the J-Class was triggered in the 1980s when Elizabeth Meyer refitted Shamrock V and Endeavour.

List of J-Class yachts

Ten yachts were built to the J-Class rule between 1930 and 1937, six in America and four in Great Britain. All three which survived were designed by Charles Ernest Nicholson: Shamrock V, Endeavour and Velsheda, of which the latter never served for an America's Cup challenge.

Other boats raced in J-Class regattas: The yachts Katoura (Starling Burgess, 1927), Resolute (Nathanael Herreshoff, 1914) and Vanitie (William Gardner, 1914) served as trial horses and most International Rule 23mR yachts were converted to the J-Class, of which three remain in existence: Astra, Cambria and Candida.

A replica of Ranger in 2004 accelerated the revival of the J-Class. Several replicas and original designs were subsequently planned for construction.

replicas or J-Class conversions    did not compete or qualify    Challengers    Defenders
Launch	Sail	Name	Designer	First ship-owner and Yacht Club	Description
1893	K1	Britannia	George Lennox Watson	Prince Albert Edward, RYS	converted to the J-Class (1931). scuttled after King George V's death (1936). replica in construction
1907	K7	White Heather II	William Fife III	Myles Burton Kennedy, Royal Albert YC	23mR converted to the J-Class (1930). scrapped to cast the lead for Velsheda (1932)
1928	JK2	Astra	Charles Ernest Nicholson	Sir Adam Mortimer Singer, RYS	23mR converted to the J-Class (1931). refitted (1987)
1928	K4	Cambria	William Fife III	Sir William Berry, RYS	23mR refitted (1995, 2001). Re-rated as a J-Class (2003)
1929	K8	Candida	Charles Ernest Nicholson	Hermann Anton Andreae, RSYC	23mR converted to the J-Class (1931). refitted (1989)
1930	JK3	Shamrock V	Charles Ernest Nicholson	Sir Thomas Lipton, RUYC	Challenger (AC1930). refitted by Elizabeth Meyer (1989).
1930	1	Weetamoe	Clinton Hoadley Crane	George Nichols syndicate, NYYC	eliminated (AC1930, AC1934). sold for scrap (1937)
1930	JUS2	Yankee	Frank Cabot Paine	John Silsbee Lawrence syndicate, NYYC	eliminated (AC1930, AC1934, AC1937). sold for scrap (1941)
1930	3	Whirlwind	Lewis Francis Herreshoff	Landon Ketchum Thorne syndicate, NYYC	eliminated (AC1930). sold for scrap (1935)
1930	4	Enterprise	Starling Burgess	Harold Vanderbilt syndicate, NYYC	winner 4:0 (AC1930). sold for scrap (1935). replica planned
1933	JK7	Velsheda	Charles Ernest Nicholson	William Lawrence Stephenson, RYS	refitted (1997). World's tallest carbon fibre mast (56m, 2008)
1934	JK4	Endeavour	Charles Ernest Nicholson	Sir Thomas Sopwith, RYS	Challenger (AC1934). refitted by Elizabeth Meyer (1984)
1934	J5	Rainbow	Starling Burgess	Harold Vanderbilt syndicate, NYYC	winner 4:2 (AC1934). eliminated (AC1937). sold for scrap (1940). replica in construction
1936	JK6	Endeavour II	Charles Ernest Nicholson	Sir Thomas Sopwith, RYS	Challenger (AC1937). sold for scrap (1947). replica (Hanuman, 2009)
1937	J5	"77C"-Ranger	Starling Burgess & Olin Stephens	Harold Vanderbilt, NYYC	winner 4:0 (AC1937). sold for scrap (1941). replica ("77C"-Ranger, 2004)
2004	J5	"77C"-Ranger	Fred Elliot/Danish Yacht	John A. Williams, NYYC	Starling Burgess & Olin Stephens replica ("77C"-Ranger, 1937)
2009	JK6	Hanuman	Gerard Dykstra	James H. Clark	Charles Ernest Nicholson replica (Endeavour II, 1936)
2010	JH1	"77F"-Lionheart	Andre Hoek		Starling Burgess & Olin Stephens original design ("77F", 1937)
building	J7	Atlantis	Andre Hoek		Frank Cabot Paine original design ("A", 1935)
building	JH2	Rainbow	Gerard Dykstra	Chris Gongriep	Starling Burgess replica (Rainbow, 1934)
in design	JS1	Svea	Andre Hoek	corporate syndicate	Tore Anton Holm replica (1937)

Specifications of the J-Class

The Universal Rule was established in 1903 by Nathanael Herreshoff and the NYYC to normalise the sailing sport at every size of boat. The J-Class was first developed in 1929 from the Universal Rule and rates boats with the following criteria:

• rating: 65<\FRAC{0.18\CDOT\TEXTBF{L}\CDOT\SQRT{SAILAREA}}{\SQRT[3]{DISPLACEMENT}}\LE76<></\FRAC{0.18\CDOT\TEXTBF{L}\CDOT\SQRT{SAILAREA}}{\SQRT[3]{DISPLACEMENT}}\LE76<>math>
  where \textbf{L}=L.W.L.+.5(q.b.l.-\frac{100-\sqrt{L.W.L.}}{100}\cdot L.W.L.)
  L.W.L.
  
  
  
  = Load Waterline Length in feet
  q.b.l.
  
  
  
  
  
  = quarter-beam length in feet
  sail area and displacement are measured in square and cubic feet
  
  
  
  
• ≤ L.W.L.
• maximum draught:
• minimum mast weight: in 1930; in 1934; for the whole rig in 1937
• standards: Lloyds' A1 scantling rules
• build: aluminium hull forbidden in the 1930s, authorised today
• design: 1930s (replicas are only rated to the J-Class provided their design dates back to the 1930s)
• racing: elapsed time (1930s), Velocity Prediction Program ratings (today)

Launch	Name	Builder	LOA	LWL	Beam	Draught	Displacement	Sail area
1930	Shamrock V	Camper and Nicholsons	119 ft 1 in	81 ft 1 in	20 ft	14 ft 9 in	134 tons	7,540 ft²
1930	Weetamoe	Herreshoff Manufacturing Company	125 ft 9 in	83 ft	20 ft	14 ft 6 in		7,550 ft²
1930	Yankee	George Lawley and Son	126 ft	83 ft	22 ft 6 in	14 ft 6 in	148 tons	7,288 ft²
1930	Whirlwind	George Lawley and Son	139 ft	86 ft	21 ft 9 in	15 ft 6 in		7,335 ft²
1930	Enterprise	Herreshoff Manufacturing Company	120 ft 9 in	80 ft	23 ft	14 ft 6 in	128 tons	7,583 ft²
1933	Velsheda	Camper and Nicholsons	127 ft 6 in	83 ft	21 ft 6 in	15 ft
1934	Endeavour	Camper and Nicholsons	129 ft 6 in	83 ft 6 in	22 ft	14 ft 9 in	143 tons	7,651 ft²
1934	Rainbow	Herreshoff Manufacturing Company	127 ft 6 in	82 ft	21 ft	15 ft	141 tons	7,535 ft²
1936	Endeavour II	Camper and Nicholsons	135 ft 6 in	87 ft	21 ft 6 in	15 ft	162 tons	7,543 ft²
1937	Ranger	Bath Iron Works	135 ft	87 ft	21 ft	15 ft	166 tons	7,546 ft²

Bibliography

• America's Cup
• Universal Rule
• J-Class Association
• Sparkman & Stephens - J-Class design
• Hoek Design - J-Class replica design
• Gerard Dykstra & Partners - J-Class refit and replica design
• New York Times - 1989 article about Elizabeth Meyer's refit of Endeavour
• youtube.com - video of Shamrock V