North American F20 Class Association
<br>Proposed -NA-F20 Class Rules 2002
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<br>NORTH AMERICAN FORMULA 20- EQUAL PERFORMANCE CLASS RULES 2002
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<br>The North American Formula 20 is a restricted class, reserved for sport catamarans, with two crew and of amateur or professional construction and destined for racing on elapsed time.
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<br>A. ADMINISTRATION OF THE RULE
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<br>A.1 AUTHORITY
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<br>The rules of The North American Formula 20 are established under behalf of The North American Formula 20 class association, which publishes the interpretations of The North American Formula 20 and recognizes them as the authorized interpretations and explanations of the rules. The North American Formula 20 class will here on will be referred to as NA-F20
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<br>A.2. ADMINISTRATION
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<br>The NA-F20 Class Association measurement committee nominates the measurers
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<br>A.3. INTERPRETATION
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<br>After having eventually consulted NA-F20 Measurement Committee, the chief measure shall give an interpretation on all points of the NA-F20. In general, what is not expressly permitted is prohibited.
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<br>A.4. REFERENCE TEXT
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<br>For the interpretation of the rules, the original text in English shall prevail over all translations.
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<br>A.5. SPIRIT OF THE RULE
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<br>In case of doubt, the intention of the rule makers, which is the spirit, shall take precedence over the letter of the rule.
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<br>A.6. DISPENSATION
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<br>Applied to existing heavier boat mast as per #-
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<br>A.7. AMENDMENTS
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<br>The NA-F20 Measurement Committee will propose amendments to the rule if necessary. Amendments shall be placed on one year’s notice unless it is considered essential to act immediately to prohibit or penalize an undesirable feature.
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<br>B. MEASUREMENT RULES GENERAL
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<br>For the construction, only the following materials are authorized: polyester or vinylester resin, glass fibers, sandwich of PVC or balsa or felt, carbon fiber in boards rudders and local reinforcing ,the combination of wood-epoxy, injected plastic, steel, extruded aluminum profiles of constant section, which shall be not altered, other than locally for the fixings and passage of equipment and normal reinforcement.
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<br>Every material that is not expressly permitted is prohibited. Epoxy glue is permitted for joining components. For the trampoline: all types (except netting).
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<br>B.1. PLATFORM
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<br>B.1.1. DIMENSIONS
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<br>The maximum overall length measured on the hulls is 20.08 ft. excluding rudder assembly.
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<br>1.2.1. The maximum overall beam is 8.5 ft.
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<br>B.1.2. BOAT WEIGHTS
<br>From 420 to 320 lb min. { see sail area to boat weight ratio scale}#-ADD HERE
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<br>B.1.3. DAGGERBOARDS AND RUDDERS
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<br>The platform shall be equipped with a pair of rudders and, if fitted, a pair of daggerboards or centerboards. The daggerboards or centerboards and rudders may use epoxy resin. Carbon may be used for the construction of daggerboards, centerboards or rudder blades.
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<br>1.3.1 Minimum weight of rudders:
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<br>The minimum weight of each complete rudder assembly comprising blade, stock and tiller is fixed at 6.6 lbs.
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<br>1.3.2. Maximum weight of daggerboards or centerboards:
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<br>The maximum weight of daggerboards or centerboards is fixed at 15.43 lbs.
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<br>Distribution of the material of daggerboard or centerboard shall be homogeneous. Ballast or mass use of whatever nature is prohibited.
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<br>B.2. RIGGING
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<br>B.2.1.THE MAST
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<br>Carbon may be used for the construction of the mast.
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<br>The perimeter of the mast shall be a maximum of 15.16 in.
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<br>2.1.3. The maximum distance between the top of the forward crossbeam and the bottom of the
<br>upper measurement band of the mainsail shall be 32 ft.
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<br>2.1.4. The maximum distance between the bottom of the mast section and the axis of the point of attachment of the highest standing rigging shall be 20.05 ft.
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<br>2.1.5. The maximum distance between the bottom of the mast section and the point over which the spinnaker can not be hoisted shall be 28.81 ft.
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<br>2.1.6. The mast shall be watertight.
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<br>2.1.7. The mast shall have a profile of constant section
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<br>The Minimum weight of the mast is fixed at 39.68 lbs.
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<br>2.1.9. A corrector weight of maximum 2.2 lbs. may be used to satisfy these conditions. This corrector
<br>weight shall be fixed at the top of the mast and shall be removable for checking.
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<br>B.2.2.THE BOOM
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<br>A loose-footed mainsail is permitted. If used, the boom shall be made of extruded aluminum profile of constant section.
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<br>B.2.3.THE BOWSPRIT
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<br>3.2.1. The bowsprit shall be made of any material. A headsail retrieval system may be used.
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<br>2.3.2. The length shall not be greater than distance, measured in total from its attachment point (on the mast or on the cross beam) to the forward upper theoretical point of the deck, more an additional –54 inches
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<br>2.3.3 The bowsprit shall be fixed and approximately on the longitudinal centerline of the boat.
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<br>B.2.4.RIGGING AND EQUIPMENT
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<br>2.4.1.The standing rigging shall be constituted at most with: 2 shrouds, 1 forestay, 1 bridle stay, an optional intermediate set of stays , 1 pair of
<br>diamond with a pair of spreaders, 2 pairs of trapeze wires.
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<br>2.4.2. The standing rigging shall be of conventional stranded steel wire (1x19). Dyform® or similar materials are prohibited.
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<br>2.4.3. It is not permitted to adjust while racing: the rake of the mast, the tension of the standing rigging, the angle or length of the spreaders, the tension of the diamonds other than by one or two turn block’s appropriately blocklable.
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<br>B.3.WEIGHT OF CREW
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<br>B.3.1.MINIMUM WEIGHT OF CREW
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<br>The combined weight of the two crew shall be a minimum of 325 lbs.
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<br>B.3.4. RESPOSIBILITY OF THE CREW
<br>To maintain min.crew weight with allowed 25 lbs max dead weight added to meet min 325 required.
<br>The respect of the weight declared is the sole responsibility of the crew, which may be controlled and
<br>protested at any time during the race.
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<br>B.4. THE SAILS
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<br>THE SAIL PLAN
<br>The sail plan size will corespond to min. boat weights from min 320 to 420 lbs.
<br>-See Weight to Sail Area ratio scale -
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<br>The sail plan comprises a mainsail, a jib and a spinnaker. The sails shall be made of a material of dacron type, or mylar® or similar and shall fit in a bag of normal dimensions. The ISAF Measurement and Calculation of Sail areas Rules shall apply.
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<br>B.4.1. MAINSAIL
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<br>The mainsail shall have a surface area of maximum in accordance with sail area to weight ratio scale , including the mast. No parts of the sail shall be above a perpendicular passing through the highest point of the halyard.
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<br>B.4.2. JIB
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<br>In accordance with S A to W ratio scale ,-either roller furling or battened type .
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<br>B.4.3. SPINNAKER
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<br> Battens and stiffening devices, except textile leech lines, are not permitted.
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<br>B.4.4. SUIT OF SAIL AUTHORISED FOR AN EVENT.
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<br>A single suit of sails is authorized for the duration of an event.
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<br>B.5. MARKING
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<br>B.5.1. MARKING OF SAILS.
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<br>All the sails measured shall be marked wit a colored sticker affixed near the clew on the starboard side.:
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<br>5.1.2. The maximum permitted area shall be on the colored stickers.
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<br>5.1.3 The actual measured area shall be on the measurement certificate.
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<br>5.1.4.The area and the dimensions of the spinnaker (SL1, SL2, SMG, SF) shall be written in an indelible manner near the starboard tack.
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<br>B.5.3. IDENTIFICATION
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<br>The number of the measurement certificate corresponding with the boat shall be written by the measurer:
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<br>-at the stern of the hull, on the inward facing sides:
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<br>-at the bottom of the mast, starboard side:
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<br>-at the starboard tack of each sail.
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<br>B.5.4. CLASS EMBLEM
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<br>The mainsail shall carry the NA-F20 logo supplied with the measurement certificate. The NA-F 20 logo will be put starboard side within 1m from the clew point.
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<br>C. DEFINITIONS AND MEASUREMENT PROCEDURE
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<br>The method employed for the measurement and calculation of sail area shall be that defined in the Measurement and Calculation of Sail Area of the ISAF.
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<br>The measurements shall be taken and expressed in feet and inches, pounds and ounces.
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<br>c.1. WEIGHT OF THE CREW.
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<br>The controlled crew weight is based on the weight on the weight of the crew in swimming costume.
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<br>c.2. CONTROL OF MINIMUM WEIGHT OF THE BOAT.
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<br>c.2.1. THE PLATFORM:
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<br>2.1.1. This shall be weighed assembled, dry and clean.
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<br>2.1.2. It comprises: the hulls, the crossbeams, the trampoline, the daggerboards or centerboards, the steering system, the mainsheet and jib traveler cars, steering compass, all the equipment normally bolted, screwed or fixed in a permanent manner on the boat and used during racing, the righting system when existing, and eventually the corrector weights specified in (B1.2.3.)
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<br>c.2.2. THE MAST:
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<br>This shall be weighed assembled, dry and clean.
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<br>2.2.2. It comprises: All the equipment normally bolted, screwed or fixed in a permanent manner on
<br>the mast and used during racing, and the diamonds with a pair of spreaders.
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<br>c.2.3. BOAT REDY TO SAIL:
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<br>The minimum weight of the boat ready to sail shall be the assembled platform conforming to rule 2.1. above and carrying the dry and clean equipment normally used for navigation: mast, boom (when exist), bowsprit, mast rigging, halyards, sheets, sails, blocks, except the safety equipment defined by Chapter E rule 2.
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<br>c.3. OVERALL LENGTH OF THE HULLS:
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<br>The overall length of the hulls, outside rudder pintles, corresponds with horizontal distance between the vertical passing through the extremity of the hulls, the boat being leveled on its waterline.
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<br>c.4. SAILS.
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<br>c.4.1. GENERAL
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<br>The intention is to establish a reliable and simple method of measuring the active surface of the entire sail plan, including the mast. In the measurement of sail area, the term sail shall be considered as defining the part of the sail outside the mast and including headboard. Crinkles that are totally outside the edge of the sail or the boltrope that is inside the mast shall not be included.
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<br>c.4.2 MAINSAIL AND JIB:
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<br>The battens shall be without tension in their pockets, the sail shall be pinned on a flat surface with the tension just sufficient to eliminate creases, then smoothed flat to give the longest dimensions.
<br>Whilst the sail remains pinned, all the measurement necessary shall be taken, the tension should not be
<br>adjusted.
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<br>c.4.3. MAST MEASUREMENT.
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<br>The measurement of the perimeter of the mast shall be considered as the distance, at right angles to the mast axis, measured around and back to the same point. The dimension shall be divided by two to give the value for the half-circumference.
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<br>c.4..4. SPINNAKER
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<br>4.4.1. Definition of a spinnaker
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<br>All triangular sails not complying with definition of a mainsail or a jib are spinnakers, on condition that the girth at mid-height is equal or greater than 75% or that of the foot
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<br>4.4.2. Calculation of the spinnaker CSPI:
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<br>CSPI=SF x SL1 +SL2 + (SMG- SF) x2 (SL1 + SL2)
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<br>4 2 3 2 Where SMG > 75 % of SF.
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<br>Where SF is the length of the foot measured around the edge of the sail between the lowest point of
<br>the luff and the leech:
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<br>Where SL1 is the length of the luff of the sail, from the highest point of the sail, to the lowest point of
<br>the sail on the luff:
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<br>Where SL2 is the length of the leech of the sail measured along the edge of the sail, from the highest
<br>point of the sail, to the lowest point of the sail on the leech.
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<br>Where SMG is the width at mid-height, which shall be taken between the mid point of the luff and
<br>the mid point of the leech.
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<br>CONTROLS.
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<br>d.1. MEASUREMENT FORM AND MEASUREMENT CERTIFICATE
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<br>d.1.1. COMPETENCE
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<br>Only the controls, measurements and calculations by a measurer recognized by the NA-F20 Catamaran Association, a National authority or the ISAF ( Multihull Committee) are considered valid.
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<br>d.1.2. MEASUREMENT FORM AND MEASUREMENT CERTIFICATE
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<br>The measurement form competed (measurement sheet and calculation) and signed by a measurer is not a
<br>measurement certificate.
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<br>1.2.2. The measurer shall record on the measurement form anything he considers as departing from the
<br>concept of the NA-F20 rule, he shall send it with detailed explanations on the contentious points to the NA-F20 Catamaran Association for a ruling.
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<br>1.2.3. The measurement certificate is issued by the NA-F20 class association responsible for the administration of the rule in the country of the owner. When after examining the completed measurement form signed by the measurer, it considers that the boat conforms to the Rules off the NA-F20.
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<br>1.2.4. A competitor has an obligation to present with his entry the measurement certificate and measurement form of his boat.
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<br>d.1.3. REGISTRATION
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<br>The measurement form (measurement sheets and calculations) and the measurement certificate are
<br>established and registered by the NA-F20 Catamaran Association or a National Authority.
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<br>d.1.4. VALIDITY
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<br>A change of ownership shall be invalidate a measurement certificate, a re-registration shall be made by
<br>returning to the national authority the initial measurement certificate accompanied by the details if the new owner. The valid certificate and registration will be returned to the new owner, it is not necessary to re-measure the boat.
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<br>All modifications or replacements of parts of a significant change shall be re measured and notification made on the measurement certificate by a measure recognized by the NA-F20 Catamaran Association.
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<br>d.1.5. COST OF THE MEASUREMENT
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<br>1.5.1.INITIAL MEASUREMENT:
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<br>The cost of measurement is at the discretion of the relevant National Authority corresponding with the provision of the class emblem, the marking stickers for the sail, the hulls, the mast and the establishment and registration of the measurement certificate.
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<br>1.5.2. The cost of additional measurement, marking and registration is fixed at the discretion of the National Authority.
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<br>1.5.3. The other (travel and accommodation of the measurer) are at the owner’s expense.
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<br>D.2. EVENT MEASUREMENT.
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<br>The travelling and accommodation expense of the measurer are the responsibility of the event organizer.
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<br>It is sole responsibility of the competitor in a race to maintain his boat in accordance with its certificate.
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<br>SAFETY
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<br>E.1.RIGHTING
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<br>The crew shall be able to demonstrate their capability to re-right the boat.
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<br>E.2. SAFETY EQUIPMENT
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<br>Minimum mandatory equipment to be on board;
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<br>1 re-righting line 13 feet long an 10mm of diameter minimum, 2 lifejackets (conforming to the rules in force.)
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<br>E.3. BALLAST AND WEIGHT JACKETS
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<br>Ballast on the boat or worn by crew is prohibited.
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<br>E.4. STEERING COMPASS
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<br>A fixed steering compass may be used
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<br>E.5. COMPLIMENTARY ARRANGEMENTS
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<br>REDUCTION OF SAIL AREA
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<br>If specified in the Notice of Race, the organizers may require the following complementary equipment: . Mainsail equipped with reefing points not less than 39.4 in from the foot.
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Great work Carl.
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<br>re: Rule 2.3.2
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<br>The pole length rule should be relative to the main beam(mast) only with no reference to the bow. There is a good reason for this. As it stands the advantage is given to all boats with a mast set farther aft on the boat, creating a larger slot between the mast and spi. I am not sure why the iF20 rules have it this way. So an overall maximum pole length should be settled on. Pick one :-)
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<br>marc (mhb)
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Carl
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<br>Thanks for the effort placed forth in these rules. But, would it not be better first to come to some general agreement before going into the details.
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<br>For example: material construction of the boom -- I feel that it should be open but limited to the same material constraints as the mast.
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<br>Please read my last post in the "which camp" string.
<br>I do not agree with setting boat minimums yet. Lets concentrate on bringing existing designs together and then formulating basic rules from existing designs.
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<br>This KISS principle will bring people in. Trying to write rules before a general agreement is established will only cause a deterioation of what is progressing here.
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<br>My humble two cents worth.
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<br>Steve<br><br>

Thanks Marc and Steve
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<br> Understand Marc may be building some 20 footers ,--
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<br>-Agree we have to get a direction from the majority of interested 20 sailors , we are just proposing and discussing all the varios options , ,I am open to numerous class rule variations ,
<br> --Will try a total crew and boat weight scale version .
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<br> The rules will need a total reorganization , good note on poles Marc ,you are right .
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<br> all the best
<br> Carl<br><br>

From sailmaking to boatbuilding ...
<br>Yes I am working on a prototype F20 (BEAUM F20) cat that will be built in NA. This is why I am interested in the outcome of the NA F20 rules. I am interested in a Formula based rule for SA vs. BW. I am not very interested in producing a 420 pound boat. It is more likely that the final BEAUM F20 will come out at under 375 pounds all up. The first 2 BEAUM prtotypes (one is already sold) will be test platforms for the hulls(all glass). They will both be sporting a 33' mast with a 12 foot beam expected to weigh around 410-420#s (one of the boats will have 6 foot pivoting racks). This is to stress the hulls well beyond what would be seen on an 8.5 foot platform with a 32 foot mast. It is not unrealistic to build ultralight boats <300#s as seen already but is in my opinion unrealistic to expect such a class to grow.
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<br>Keeping the rules simple is the way to go.
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<br>re: spi pole ... Any material for construction should be allowed. I will be using alluminum windsurfer masts as they are selling at windsurfing swap meets for $50CA , can't beat that !
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<br>Keep up the good work
<br>Marc<br><br>

just athought on the rules you are creating, the mast rule that you are proposing eliminates Tornado masts, why do you want the mast to be a constant section, one of the principal benefits of carbon masts is that you can vay wall thickness.
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<br>john pierce<br><br>

Excellent point John thanks ,-agree
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<br>-This is just a quick rehash of the existing iF RULES , why they wanted a constant section is due to their efforts to control costs and expensive aspects .
<br> We need to reorganize all aspects of the rule and review each catagory with some expert advice by people with current practical experience in that particular area --{carbon mast builders }--Do you have current costs on C F masts in radius section .
<br> thanks much ,-all info is greatly appreciated . <br><br>

Expect to pay around $1700 for the tube, p.s I should have pointed out that I am the manufacturer of the Stealth which has a tapered carbon mast so I do have a potential commercial interest in your project<br><br>

Thankyou John -
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<br> Can you give us a boat builders perspective on what 20 foot cats should weight , and how we should proceed to draft a formula for racing all the various 20 existing cats and the ones that will be .
<br> Obviously we are just in the rules proposal concept stage ,-and open to all .
<br> thanks again .<br><br>

the rule states that the mast is to be of a constant section. on the outside. some of the older a-cats tapered their aluminum masts on the inside.<br><br>

The rule is a bit ambiguious about wall thickness and could be read that a constant profile means both inside and outside of the wall. How can you possibly taper an aluminium mast on the inside?
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<br>In reply to sail 6000's q about weight, how much do you guys have to pay for an inter 20 or a hobie fox, cost will refect the weight the boat can be built to. <br><br>

Rule says :"... extruded aluminium profiles of constant section, ..."
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<br>Section here myst therefor refer to crossection, especially becuase it is not possible to produce non constant crosssecctions (Taper) by the production methode called extrusion.
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<br>Wouter
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<br>Also a mechanical engineer
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Thanks John
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<br> The policically correct , clever answer on boat weight .
<br> There is a good post by Maurizzio on the open forum ,quotting Dick Newick on weight cost considerations, same answer with a little more detail and info.
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<br>-We are trying here in the U S , but have inherited a mess of conflicts to try to resolve.
<br> All the best -
<br> Carl <br><br>

I was not trying to be clever I really wanted to know how much the boats cost new in the USA!!<br><br>

just joking a little with ya John ,
<br> paid aroung 14 k for the Inter 20 with an added snuffer and pole plus some goodies . that was 2 years ago , purchased to sail the Worrell .
<br>
<br>-Can you give us an opinion on going the direction of similar iF 20 rules , but larger sail area and lighter weight , maybe just beyond the Inter 20 in both regards ,--210 mainsail , and 390 -385 LB weight .
<br> thanks ,--we try not to take ourselves too seriously , we are here to sail or talk sailing and have fun .
<br>
<br> All the best
<br> Carl
<br>-<br><br>

I know you were!
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<br>I think you've got a hard job to keep everybody happy here,
<br>
<br>With F16hp the three main boats were all very similar and even then it took a lot of work (mainly done by Wouter)
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<br>There are quite big variances in the boats that you need to get to the same speed.
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<br>The other problem that you have is that it seems to me that the inter 20 is the quickest of the boats that you are looking at, and you want to make the class quicker still.
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<br>I've no problem with the latter the quicker the better, but it puts the older, slower designs even further behind.
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<br>Someone has already suggested just putting a handicap limit and then allowing anyone to sail any boat as long as its handicap was at or below your limit. I think this may be a good way ahead, it allows anyone to join in and they have a choice of ways to bring their boat up to your speed.
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<br>As regards moving forward on weight reduction, someone else suggested a two tier system, again it could be done with a handicap limit, say 3% lower than standard.
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<br>This way if people wanted light boats, they could use small jib and spinnaker sails at standard h'cap until you get enough boats to run races in the faster group.
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<br>As regards weight/ sail area, I see no reason why you couldn't get a twenty foot by 8.5 ft cat down to around 320 lbs for the kind of money you are currently paying for the inter.
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<br>I think if you sailed at this weight you wouldn't need to increase sail area, the Isaf handicap system predicts that this would be 4-5% quckerthan a current 390lb boat, i'm sure texel would say the same and I'm sure tthe boat would perform, my only query would be that it would be aboat for heavyweights as you would lose quite a lot of righting moment, but I guess from your comments you want more power anyway.
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<br>There you go, my 2 cents worth as you American chaps say!!!<br><br>

Thankyou John -
<br> Greatly appreciate the information ,-a 320 LB -20 ft cat with chute has great appeal to me ,
<br>
<br>-Also proposed a sail area to weight rating scale ,-it is under the review 11-16-01 post .
<br>-It is overly generous with sail area to older existing heavy active raciing 20s but graduates the scale down to a 320 boat weight with slightly less sail area than existing IF 20 cats .
<br> Can you comment on this rating proposal .
<br>
<br> thanks for your time ,
<br> Carl<br><br>