The J Class

Featured in Model Yachting #127

Robert Eger's J-Boat "Shamrock V"
by Linda Dennis, San Diego, CA.

Class Secretary

John Hanks, III
1849 Rainbow Ave. So.
Lake Havasu City, AZ 86402
928-680-7331

Description

The models in the J class are 1/16 scale hulls of the J class yachts that raced for the America's Cup from 1930 through 1937. The models are the largest recognized class in the AMYA with the hulls ranging from 7ft to 8 1/2ft in length and weighing between 65 and 90 pounds. The models carry from about 3500 to 4500 square inches of sail on masts ranging from 8 to 10 feet in height. The differences in sizes of the models comes from the fact that the full size boats were built to a formula and different measurements could be used within the formula to get the same answer. The full sized boats varied from about 120 to 135 feet in length and had a water line length of between 65 and 87 feet and they carried a crew of about 35.

There were 13 full size J boats built in both the U.S. and Great Britain. In addition there were about 3 other existing yachts that were converted to meet the J class rules. Drawings are available for all of the yachts designed as J boats and there are 3 hulls produced in fiberglass. The 3 fiberglass hulls are of Enterprise, Shamrock V and Whirlwind. Shamrock V is the only one still in production but examples of the other 2 hulls are available form private parties from time to time. Most of the J class models are one of examples built from drawings in either wood or fiberglass.

The J class is truly one of the most beautiful class of models in AMYA.

Visit the J Class Sitefor more detailed history and current state of the fleet!

Official AMYA Class Rules

J Class Rules (Effective 1 -1-2002)

1.0 HULL

1.1 Must be a scale model of one of the original "J" boats. 

1.2 Scale must be ¾ inch equals one foot. 

1.3 Exception: The keel draft can be two inches deeper than scale to help the stiffness of the model.

2.0 MAST

2.1 Height: Mast height may be to scale of the yachts original sail plan. Not to exceed 10 feet. (1988) 

2.2 Material: The mast is to be constructed of Wood or Aluminum.

3.0 SAILS

3.1 No restriction on sail area other than sail area may not exceed the scale sail plan area. 

3.2 Any sail plan that was used by the original boat from which the model was scaled, i.e. double head sails, Genoa, Spinnakers, etc. 

3.3 Maximum sail area for each model is as follows; 
Whirlwind - Whirlwind and Vanguard hull - 2478 square inches 
Whirlwind 1/16 scale - 4128 square inches 
Weetamoe - 4247 square inches 
Yankee - 4100 square inches 
Enterprise - 4265 square inches 
Shamrock V - 4241 square inches 
Rainbow - 4238 square inches 
Endeavour - 4253 square inches 
Ranger - 4245 square inches 
Endeavour II - 4243 square inches

4.0 RUDDER

4.1 Must conform to the original boat from which it was scaled. 

4.2 Exception: The rudder may be two inches deeper to follow the extended keel and two inches wider to provide extra maneuvering control.

5.0 DECK

5.1 The deck shall be made from a hard material such as wood, fiberglass, Formica or some similar material. Fabric and film decks are not allowed.

6.0 Displacement 

6.1 Each model yacht shall have a minimum ready to sail weight, that is the weight of the model when it is ready to race. 

6.2 The weight of the model shall not be changed once a regatta has begun. A regatta is defined as a race or series of races that constitute an event regardless of the number of days the event covers.

6.3 The minimum displacement for each model is as follows; 
Whirlwind - Whirlwind and Vanguard hulls - 63 pounds 
Whirlwind 1/16 scale - 77 pounds 
Weetamoe - 69 pounds 
Yankee - 72 pounds 
Enterprise - 62 pounds 
Shamrock V - 65 pounds 
Rainbow - 68 pounds 
Endeavour - 69 pounds 
Ranger - 81 pounds 
Endeavour II - 79 pounds

Effective January 2002