Official J Class Website

*Effective 1/1/11     NOTE*   2.3 has been Amended as per the Class Sec. John Hanks.

This is the most current version and will go into effect as noted.

Description

The J Class models are 1/16^th scale hulls of the J Class yachts that sailed for the America’s Cup from 1930 through 1937 as well as the yachts that were converted to the J Class and competed with the America’s Cup yachts in club regattas. The models are the largest recognized class in the AMYA with hull lengths ranging from about 7 feet in length to 81/2 feet in length and weighing between 65 and 90 pounds. The models carry from about 3,000 to 4,000 square inches of sail on masts that are 8 to 91/2 feet above the deck. The difference in sizes of the models is driven by the different sizes of the full size yachts. The Js were designed to a rule with a specific formula that allowed the designers to change dimensions of the hulls and sail area to arrive at the same answer. The full size yachts varied in size from about 120 to 135 feet in length and had waterline lengths from about 76 to 87 feet and carried a crew of about 35 professional sailors.

There were ten yachts built to the J specifications between 1930 and 1937, six in America and four in Britain to compete for the America’s Cup. Another eight existing large yachts sailing at the time were converted to J specifications for use as trial horses and as competitors in local yacht club regattas. Drawings for all of the original J yachts and those converted to the J class are available from several museums such as the Mystic Seaport Museum, the Smithsonian and the Herreshoff Maritime Museum. There are also several companies producing fiberglass hulls for some of the yachts. The hulls that are currently available in fiberglass are Ranger, Endeavour, Shamrock V and Whirlwind. The scratch building of hulls from drawings in either fiberglass or wood is encouraged in the class. Masts and spars in extruded aluminum are also available for skippers who wish to build their J model. Keep in mind that there will be some scratch building required when you build your J model regardless of whether you begin with a fiberglass hull or want to build a plank on frame model.

The J Class is truly one of the most beautiful class of models in the AMYA reflecting the sailing power and grace of the original classic yachts of the 1930s.

The OFFICIAL J CLASS RULES:

January 1, 2011

J

AMYA Class Specifications for the

J Class Model Yacht

1. GENERAL

   1. The J Class Model Yacht is a restricted design model yacht class. The purpose of these rules is to create a class that represents the spirit and beauty of the original J Class Yachts as they sailed in the 1930s. In that vein the hull and deck must be as close to the original as possible in shape unless otherwise specified in the rules

   2. The boat, not the skipper is entered into events. Changing skippers during an event shall be permitted.

   3. As necessary, interpretations of the Class Specifications may be requested from the Class Secretary. When issued, interpretations shall be communicated to all class members through the AMYA Quarterly magazine and the J Class web site.

      1. Interpretations are to be temporary to allow class members to challenge them and call for a class vote using the annual AMYA ballot to accept or reject a specific interpretation.

      2. Interpretations not challenged within one year of issue shall become permanent and incorporated in any subsequent revisions of these specifications.

   4. Line Drawings

      1. Line drawings in 1/16 scale by Serrao, Taglang, Chevalier, Maine Maritime Museum and M.I.T.are accepted by the class as being within the level of accuracy required.

      2. Line drawings not listed above shall be submitted to the Class Secretary for approval.

2. HULL

   1. Hulls shall be a scale model of the yachts listed in the chart in section 10.

   2. Scale shall be ¾” equals one foot, also known as 1/16 scale. The exception being the 5/8” scale Whirlwind, which was produced by Vanguard and Whirlwind Model Yachts.

   3. Exception: the keel draft may be two inches deeper than scale. This additional 2" shall be added to the bottom of the original keel as drawn and shall be fair with the lines of the original hull as drawn. (wings, bulbs, widening of the keel etc. shall not be permitted)

   4. Centerboards scaled to original dimensions shall be permitted.

   5. Hull material is not restricted.

   6. Minimum bare hull weight shall be 9 pounds. Hulls built and registered with the Class Secretary before 1/1/2011 shall be exempt from this requirement.

3. DECK

   1. The deck shall only be constructed from a hard material such as wood, fiberglass (which may have a wood core), and/or Formica.

   2. Fabric & film decks are not permitted.

   3. The deck sheer line shall be a fair and continuous curve.

   4. Original topical deck structures, furniture and fittings may be omitted.

4. RUDDER

   1. Rudder shall conform to the original boat from which it was scaled.

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

   3. There are no material restrictions on the rudder.

5. RIG

   1. A spar shall be all aluminum, all wood, or a composite of wood with an interior reinforcing core of any material. The exterior of a composite reinforced mast shall be uniformly wood.

   2. Mast height may be to scale of the yachts original sail plan, not to exceed 10 feet.

   3. Booms

      1. Booms shall be either a scaled version of the boom used on the full size boat or linear without a permanent bend or curve.

      2. Jib booms, including counter weights, shall not extend beyond the bow. In the case of a boat whose original design includes a bow sprit, the jib boom shall not extend past the bow sprit.

   4. There are no material restrictions on rigging as defined by the Equipment Rules of Sailing.

   5. Rotating masts or “swing rigs” are prohibited.

6. SAILS

   1. Sail area limits are defined in the chart in section 10.

   2. Any sail plan used by the original boat from which the model was scaled, i.e.: double head sails, genoa, spinnakers, etc. may be used.

   3. Spinnakers shall be unmeasured sail area.

   4. Self-tacking jibs may be used in place of original foresail plan.

   5. Sail Roach

6.5.1. Main sail roach shall not exceed 3”.

6.5.2. Foresail roach shall not exceed 2”.

6.5.3. The head of each sail shall not exceed 1.5”.

6.5.4. The roach of each sail shall be a fair and continuous curve from head to clew.

6.5.5. Sails built before 1/1/2011 shall remain legal.

7. WATERLINE

   1. Required load waterline length is defined in the chart in section 10.

   2. Once measured for an event, no alterations shall be made that alter the waterline length, draft or displacement, except as noted in Section 7.4.

   3. For events where the waterline length, draft and/or displacement are not measured, alterations shall not be made after the first race except as noted in Section 7.4.

   4. Notwithstanding Section 7.2 & 7.3 jib boom counterweights may be adjusted or changed at any time.

8. RADIO FUNCTIONS

   1. There are no restrictions on the scope or the amount of radio functions.

9. OPTIONAL ITEMS

   1. Radial jib fittings may be utilized.

10. YACHTS