1. General
a. The official language shall be English.

b. The official measurement system shall be Metric

2. Royalty
a. A Royalty of NZ$10 per boat built shall be payable to the designer, either directly or through the 3.7 Owners Association.
 
b.  Sail numbers and registration certificates shall not be issued until proof of payment of Royalty or purchase of plans has been produced.

3. Registration
a. The 3.7 Owners Association will issue a registration certificate to each boat when the following conditions have been fulfilled:

i. Measurement form, completed by an official measurer, is produced and accepted by the Owners Association if any doubt exists as to compliance with the Class Restrictions.

ii. Payment of Royalty, registration fee, measurement fee and current Association dues have been made, as set down by the Owners Association.

b. No two boats in the same country shall have the same name.

c. Change of ownership invalidates the certificate, but re- registration may be effected by returning the old certificate to the Owners Association, together with details of new owner and re-registration fee, if any, whereupon a new certificate will be issued.

4. Measurement
a. This is a one-design class. Measurement tolerances are intended to allow for genuine building errors only and shall not be deliberately used to alter the design. Measurement shall be carried out using these rules in conjunction with the class plans and measurement diagram(s). The measurer shall report on the Measurement Form anything he considers to be a departure from the intended nature and design of the boat, or to be against the general interest of the class, and a Registration Certificate may be refused, even if the specific requirements of the class rules are satisfied. Also, Registration may be granted to a boat which does not comply with the specific requirements of the class rules if in the opinion of the Owners Association, the departures are due to genuine building errors only, and can only adversely affect the performance of the boat. Any such departures shall be entered on the Registration Certificate.

b. Any templates used in measuring hulls shall be made from reproductions of the original full size sections drawing. Such reproductions shall be made by contact process onto stable film (e.g. polyester).

c. Only official measurers, appointed by the Owners' Association may measure a boat and sign the measurement form.

d. A measurer shall not measure a boat owned or built by himself.

e. It is the responsibility of the owner to ensure that the boat is correctly measured and to ensure that it is thereafter complies with the current Class Rules. All boats shall be liable to re-measurement at any time, but only by an official measurer.

5. Construction
a. Boats may be either amateur or professionally built.

b. The hull shell (not including stringers frames or similar stiffening) may be built only of wood, foam sandwich, glass reinforced plastic, kevlar, carbon fibre, or any combination of these materials.

c. Each panel of the hull shell (i.e. bottom, side, deck) with the exception of false floor and side bulkheads, shall be of uniform thickness over its entire area. This rule does not apply to butt straps for joining plywood or reinforcing under frames or other internal structure and is intended to prevent concentration of weight amidships. If measurement of shell thickness is taken (by check holes) a tolerance of 15% of the maximum thickness will be allowed.

d. Boats built of glass reinforced plastic shall have at least 40kg of positive buoyancy secured in the hull. (To comply with the Y.N.Z. requirements).

e. All composite standard hulls being constructed after 18 April 2003 shall be checked during joining of hull topsides and bottomsides by a measurer who shall ascertain that weight is spread evenly with no undue concentration of heavy materials amidships, and that the hull is already close to 40kg in weight. This shall be noted on the hull’s future Registration Certificate.

f. The centrecase and surrounding areas may not be constructed of materials heavier than those used in constructing the rest of the hull.

g. Extra-lightweight composite hulls may be built only with provision for removable prodder and gennaker, and will have different weight rules (Section 8). These hulls need not weigh close to 40kg when topsides and bottomsides are joined.

6. Hull Measurement
a. The hull shall be measured in a measuring jig as shown in the measuring jig diagram. The measuring jig is to be constructed with alloy templates at the station positions of the Class Plans, a stem profile and a transom template. The whole jig is to be set up so that its shape corresponds with the designed shape plus the maximum tolerance all over. Templates will be marked with maximum and minimum tolerance positions of the sheer. (The sheer is the point where the top of the deck and the outside of the side meet). Templates shall be attached to the jig and shaped as shown in the measuring jig diagram so as to allow them to shift sideways and rotate in their vertical plane to allow for any horizontal bond or twist that the hull may have.

b. The hull shall be measured by placing it in the jig and checking that it does not depart from the templates more than twice the tolerance and that the sheer lies between the maximum and minimum position. The sheer should be a fair continuous line.

c. The hull tolerance with the exception of the transom shall be plus or minus 5mm and the vertical sheer position tolerance shall be plus or minus 6mm. Additional 1mm camber on topsides at station one only is allowable.
 
d. There shall be a capping or similar projection outside the hull over the full length of the boat which shall project 20mm (plus or minus 8mm) from the side of the hull. (On glass reinforced plastic hulls this capping may also extend forward of the stem no more than 25mm.) This capping may be rounded into the hull surface within 25mm of each end of the boat. The extension of decking over the edge of the hull does not constitute a capping. No foot stops or other hull protrusions shall be allowed that increase the righting moment.
 
e. The centrecase slot shall be located between 1400mm and 1750mm from the aft face of the transom, measured along the keel of the boat, and shall not be more than 24mm wide.
 
f. On glass reinforced plastic hulls the deck and cockpit moulding may overlap the aft end of the hull moulding provided such overlap does not form an extension to the bottom surface of the hull.

7. Deck and Cockpit Measurement

a. When the hull is being measured, station positions shall be marked on the sheer and the shape of the deck and cockpit checked using templates at each station.

b. Tolerance to be plus or minus 15mm.

c. The cockpit shape need not be measured at station 2 or 4. The measurer shall satisfy himself that the cockpit at stations 2 and 4 approximates the design shape. The cockpit may be terminated at the aft end of the foredeck in the form of a V- shaped bulkhead.

d. The cockpit may only drain through the transom and/or the centrecase.

e. The transom may be either open to the cockpit or closed in.

f. The sidestay chainplates shall be located not less than 300mm aft of station 2 and shall be fastened on the outside of the hull.

g. The foredeck must extend from the bow of the boat to, or aft of, straight lines joining the centre at station 2 and the centre of the sidestay chainplates.

h. The mast step shall be located so that the forward side of the mast is 1190mm aft of the bow, plus or minus 30mm.

i. The mast shall be stepped on deck with the bottom of the mast not more than 40mm above the deck.

j. Normal cockpit stringers shall not be subject to measurement.

8. Weight
a. The boat shall be weighed with all gear and fittings which are fastened to the boat excluding all blocks, ropes, shackles, wire, but including toestraps, mainsheet traveller, and compass(es), in a dry condition.

b. The weight shall not be less than 50 kg.

c. Weight correctors up to 5kg in weight may be attached to the bulkhead at station 2 above the false floor, and details of such shall be entered on the measurement form and Registration Certificate.

d. Extra-lightweight composite hulls with provision for detachable prodder and gennaker shall weigh at least 35kg with no weight correctors.

e. For such hulls to qualify as standard hulls, up to 15kg of weight correctors shall be attached as follows: the first 5kg shall be attached to the bulkhead at station 2 above the false floor.  The remainder (up to10kg) allowed shall be divided into halves. One half shall be attached to either the foredeck or the interior of the prodder tube, within 300mm of the bow. A measurer must be able to check easily the size and location of lead weights in the prodder tube. The other half shall be attached to the cockpit floor or sides (one quarter each side) within 300mm of the transom.

9. Rudder and Centreboard
a. Rudder and centreboard may be of any shape or constructions, provided that the centreboard does not exceed 1370mm in length (measured along the board in any direction, including all fixed handles, etc.)

10. Mast and Rigging
a. The mast section and rigging shall be optional, except that:

1. Overall length of mast (excluding any base pins or tenon) shall not exceed 6150mm.

2. The maximum dimension of any section of the mast shall not exceed 80mm.

3. No standing rigging shall be capable of being adjusted whilst racing.

b. Contrasting coloured bands at least 10mm in width shall be painted on the masts and the distance between the lower edge of the top band and the upper edge of the lower band shall not exceed 5664mm. The top of the headboard of the sail shall not be hoisted above the lower edge of the top band. The top edge of the boom (including track) or its extension shall not, when the sail is set, intersect the aft side of the mast (including track) lower than the top edge of the lower band.

c. Masts may be constructed from the following materials: wood, aluminium alloy, glass reinforced plastic, kevlar, carbon fibre.

d. Only one mast may be used at any contest or series of races except with permission of the Race Committee controlling those races.

e. Prodders must be removed for racing in standard 3.7 contests.

11. Boom
a. Booms may be constructed from the following materials: wood, aluminium alloy, glass reinforced plastic, kevlar, carbon fibre. Booms may be of any design except that:

1. The maximum dimension of any section shall not exceed 100mm.

2. There shall not be more than 15mm vertical permanent bend in the length of the boom.

b. A contrasting coloured band at least 10mm in width shall be painted on the boom, the inner edge of which shall not be more than 2235mm aft of the aft face of the mast (including track) measured along the line of the boom when the boom is in sailing position.

12. All Sails

a. Class Insignia and numbers are to be as shown on the sail plan.

b. Double-luffed sails are prohibited. Loose-footed sails are permitted.

c. On loose-footed sails the distance from the head point to the mid foot shall not exceed 5900mm.

d. Leech measurements are to be taken to the outside of any bolt ropes (or their extension if necessary).

e. Only one sail may be used in any contest or series of races, except with the permission of the Race Committee controlling those races.

f. Sails shall be endorsed with measurer’s signature and date when found to measure correctly.

 

Sails (prior to 1 August 1999)
Sails constructed under these original rules will have the option of being measured under this  system until 1/8/2004.

a. The sail is to be measured in a dry condition at ambient temperature and in accordance with measurements and instructions on sail, rig, and fittings drawing (sheet 5) of the Class Plans.

b. Any hollows in the leach are to be bridged by straight lines.

c. There shall not be more than six batten pockets in the sail.

d. The position and length of battens is optional.

e. The maximum width of the headboard is to be 102mm, this measurement being the width of the actual headboard only.

 12. Sail (1 August 1999 onwards)
 a. Sails shall be measured in conjunction with the ISAF Racing Rules and ISAF Equipment rules of sailing. The Class rules shall take precedence where there is any conflict.

 b. Sails may be made from any material capable of being folded back onto itself without any permanent damage. Primary reinforcement may extend a maximum of 320mm from each corner of the sail. Multiply sails are allowed, but double-surface or inflatable sails are prohibited.

 c. The sail shall have a maximum of six battens. Each batten pocket shall not exceed 60mm in width.

 d. The leech of the sail shall not exceed 5766mm.

 e. Girth measurement points shall be established on the leech by measuring down from the head point 800, 1800, 3200, and 4500 mm.

 f. Girths shall be measured from each girth measurement point on the leech to the nearest point on the luff. These shall not exceed 685, 1225, 1770, and 2095 mm respectively.

 g. The distance from the head point to the mid foot shall not exceed 5900mm.

13. Equipment
a. Each boat shall have fastened on the foredeck, within 305mm of the bow, a towing eye or other suitable fitting for attaching a towline.

b. Equipment allowed for sail-rig control: Mainsheet system; traveller (if any); blocks; cleats; kicking strap (boom vang); luff tension control; adjustable foot - all of optional type.

c. Each boat shall have a halyard with which it is possible to lower the sail from within the boat while afloat. This shall be tested.

14. Crew
a. Shall consist of one person.

b. The only hiking assistance devices allowed are trapeze and toe straps, both of which may be of any type.

15. Miscellaneous
Any item which a measurer considers may not be in compliance with the Class Restrictions or Objects of the Class Restrictions shall be considered prohibited until a ruling is obtained from the Owners Association.