The 18HT is an open class of high performance catamaran carrying a Mainsail and Spinnaker, and sailed by two persons. 18HT class rules are open class rules: what is not expressly prohibited is permitted.
18HT Fundamental Rules:
The platform shall consist of two mirror image hulls rigidly fixed together in parallel
Maximum Platform Length: 5.50 m
Maximum Platform Beam: 2.50 m
Minimum Weight: 130.0 kg
Maximum Mainsail Area (including mast): 20.00 m2
Maximum Spinnaker Area: 20.00 m2
Maximum Mast Height: 10.50 m
Maximum Spinnaker Pole Length: 0.80 m beyond bows
The crew shall be two persons
Part I - Administration
A. General
A.1. Language.
A.1.1. The official language of the class is English and in cases of dispute over translations the English text shall prevail.
A.1.2. The word “shall” is mandatory and the word “may” is permissive
A.2. Abbreviations:
A.2.1. ISAF - International Sailing Federation
A.2.2. MNA - ISAF Member National Authority
A.2.3. ICA - International 18HT Class Association
A.2.4. NCA - National 18HT Class Association
A.2.5. ERS - Equipment Rules of Sailing
A.2.6. RRS - Racing Rules of Sailing
A.3. Authorities And Responsibilities
A.3.1. The international authority of the class is the ISAF which shall cooperate with the ICA in all matters concerning these class rules.
A.3.2. No legal responsibility with respect to these class rules, or accuracy of measurement, rests with: the ISAF; the MNA; the ICA; the NCA, the certification authority or an official measurer. No claim arising from these class rules can be entertained.
A.3.3. Notwithstanding anything contained herein, the certification authority has the authority to withdraw a certificate and shall do so on the request of the ISAF.
A.4. Administration of the class
A.4.1. ISAF has delegated its administrative functions of the class to the MNAs. The MNA may delegate part or all of its functions as stated in these class rules to an NCA
A.4.2. In countries where there is no MNA, or where the MNA does not wish to administrate the class, its administrative functions as stated in these class rules shall be carried out by the ICA which may delegate the administration to an NCA
A.5. Spirit of the Rule
A.5.1. In the case of doubt, the spirit of the rule shall take precedence over the letter of the rule.
A.6. ISAF Rules
A.6.1. These class rules shall be read in conjunction with the ERS and the RRS.
A.7. Advertising
A.7.1. The 18 HT class adopts ISAF Category C
A.8. Notice of Race and Sailing Instructions.
A.8.1. These class rules shall not be varied by Notice of race or sailing instructions except as provided by Articles B.3.5.4; B.4.1.5; B.5.3.
A.9. Amendments to these Class Rules
A.9.1. Amendments to these class rules shall be proposed by the ICA and are required to be approved by the ISAF in accordance with ISAF regulations.
Note: The procedure for proposing amendments to these class rules is incorporated in the constitution of the ICA
A.10. Interpretations of these Class Rules
A.10.1. Interpretations of these class rules, except as provided by A.10.1.1shall be made in accordance with ISAF Regulations.
A.10.1.1. Any interpretation of these class rules required at an event may be made by an international jury constituted in accordance with the RRS. Such interpretation shall only be valid during the event and the organizing authority shall, as soon as practical after the event, inform ISAF, the MNA and the ICA.
A.11. Sail Numbers
A.11.1. Sail numbers shall be issued by the MNAs
A.11.2. A building permit issued by the ICA shall be submitted to the MNA prior to sail numbers being issued for all boats registered after January 1, 2004.
A.12. Class Fees and Building Permits
A.12.1. For all boats to be registered after January 1, 2004, builders shall be required to pay a fee to the ICA (the Class Fee) before being issued a building permit.
A.12.2. It is the builder’s responsibility that the completed platform complies with theses class rules.
A.12.3. The Class Fee shall be set from time to time by the ICA, and different fees and fee structures may be charged for different levels of production.
A.12.4. The Class Fee may be collected by the MNA on behalf of the ICA.
A.13. Measurement and Certificates
A.13.1. As of January 1, 2004, all 18HTs shall require a valid measurement certificates for the platform, each mast, and each sail. Measurement certificates shall be issued by the MNA.
A.13.2. Sails. Each sail shall carry a measurement sticker or stamp issued by the MNA or the NCA, signed and dated by the sailmaker or a class measurer. The sticker shall clearly indicate the measured area of the sail. The sticker shall be on the starboard side of the sail, within 300 mm of the tack point.
A.13.2.1. A sailmaker may perform a provisional measurement and certify the sail, however, a complete measurement form including all measurements and calculations must be submitted and certified by the sailmaker to the MNA
A.13.2.2. The MNA may revoke this measurement privilege if it finds a consistent pattern of abuse or errors in excess of 2% of stated area.
A.13.3. Each mast shall carry a measurement sticker issued by the MNA, signed and dated by the mast builder or a class measurer. The sticker shall clearly indicate the measured area of the mast. The sticker shall be on the starboard side of the mast at approximately the height of the Mainsail tack.
A.13.3.1. A mast builder may perform the initial measurement and certify the mast, however, a complete measurement form including all measurements and calculations must be submitted and certified by the mast builder.
A.13.3.2. The MNA may revoke this measurement privilege if it finds a consistent pattern of abuse or errors in excess of 2% of stated area.
A.13.4. All boats, including sails and masts shall be measured prior to the start of National, Regional or World Championship Events, or as provided in the Notice of Race or Sailing Instructions for other class events.
A.13.5. It is the responsibility of the Skipper to ensure that the boat shall comply with these class rules for all events. Compliance shall be subject to protest.
Part II – Requirements & Limitations
B. Requirements & Limitations
B.1. General
B.2. Crew
B.2.1. The Crew shall consist of 2 persons
B.3. Boat
B.3.1. Platform
B.3.1.1. The Platform shall consist of 2 mirror image hulls permanently joined together when racing
B.3.1.2. Each hull shall be symmetric around its own centerplane, which centerplane may not be vertical when the boat is level.
B.3.1.3. The hulls shall be substantially parallel.
B.3.1.3.1. The minimum distance between the hulls shall not be less than the maximum width of the platform less the combined maximum beam of the hulls.
B.3.1.3.2. The beam of the hulls shall be the horizontal distance between the vertical falls passing through the widest point of the hull measured with the cross beams level.
B.3.2. Dimensions
B.3.2.1. The hull length of each hull shall not be greater than 5.50 m excluding fittings. (See ERS D.3.1).
B.3.2.1.1. For purposes of measuring the hull length, the boat shall be resting with the bottoms of the fore and aft cross beams level with each other.
B.3.2.2. The width of the platform shall not be greater than 2.50 m.
B.3.2.2.1. The width of the platform shall be measured between the vertical falls passing through the widest point of the platform measured with the cross beams level, including equipment in its normal sailing position
B.3.2.2.1.1. The following shall be excluded from the measurement of the maximum width: Trapeze gear, footstraps, and Daggerboards or Bilgeboards in their retracted position.
B.3.3. Weight
B.3.3.1. The weight of the boat in dry conditions shall not be less than 130 kg. The weight shall be taken including all equipment used in sail racing, including sails and battens, and excluding personal equipment.
B.3.3.2. Ballast shall be prohibited.
Note: Ballast is defined in ERS C.2.5. as weight installed to influence the stability, flotation, or total weight of the boat.
B.3.4. Corrector Weights
B.3.4.1. Corrector weights shall be fixed to the outside of the forward cross beam.
B.3.4.2. Corrector weights shall not exceed 4.0 Kg
B.3.5. Hull Appendages
B.3.5.1. Foils designed to lift the boat clear of the water are prohibited. The thickness of the section of hull appendages shall not exceed 50.0 mm. Appendages shall be straight or of constant radius.
B.3.5.2. “T-Foils” shall be permitted for the rudder only. A T-Foil is defined as a vertical rudder foil with a horizontal “T” at its lower extremity.
B.3.5.2.1. The width of the horizontal “T” shall not exceed 35.0 cm
B.3.5.2.2. The horizontal “T” must be rigidly fixed to the vertical rudder surface and the angle of the horizontal “T” shall not be adjustable in any way while sailing.
B.3.5.2.3. The thickness of the section of the vertical rudder foil shall not exceed 50.0 mm
B.3.5.3. Each Daggerboard or Bilgeboard or Centerboard shall weigh not more than 6.0 Kg. Distribution of material in the Daggerboard or Bilgeboard or Centerboard shall be homogeneous. Ballast or mass use of whatever nature shall be prohibited.
B.3.5.4. Only one complete set of hull appendages shall be used in any Class Event, except when a hull appendage has been lost or damaged beyond repair, unless explicitly permitted by the Organizing Authority in the Notice of Race. A complete set of hull appendages for a platform shall include one set of appendages for each hull.
B.4. RIG
B.4.1. Mast
B.4.1.1. The Mast Length shall not exceed 10.50 m (See ERS F.7.1)
B.4.1.2. The circumference of the mast shall not exceed 500.0 mm
B.4.1.3. The Area of the mast shall be ½ times the circumference times the Mast Length. For tapered sections, the average circumference shall be used. (See Measurement Form).
B.4.1.4. The distance from the top of the beam to the Rigging Point where the forestay and/or shrouds are attached (the highest Rigging Point) shall be between 6.88 m. and 7.28 m. (See ERS F.7.4)
B.4.1.5. Only one mast shall be used in any class event, except when a mast has been lost or damaged beyond repair, unless explicitly permitted by the Organizing Authority in the Notice of Race.
B.4.2. Boom
B.4.2.1. The maximum height of the boom shall not exceed 2 times its average width.
B.4.3. Bowsprit
B.4.3.1. The boat may carry a single bowsprit for purposes of attaching the tack of the spinnaker.
B.4.3.2. The length of the bowsprit measured to the tack point shall not be greater than the distance from its attachment point on the mast or cross beam to the upper leading edge of the bows, plus an additional 0.80 m.
B.5. Sails
B.5.1. The sailplan shall include one Mainsail and one Spinnaker.
B.5.2. Boats shall carry only one Spinnaker and one Mainsail while racing.
B.5.3. Only one mainsail and one spinnaker shall be used in any class event, except when a sail has been lost or damaged beyond repair, unless explicitly permitted by the Organizing Authority in the Notice of Race.
B.5.4. Mainsail
B.5.4.1. The combined area of the Mainsail and of the Mast shall not exceed 20.00 m2. The area of the Mainsail shall be calculated in accordance with the latest ISAF sail measurement guidelines (See Measurement Form).
B.5.4.2. Mainsail shall be a Soft Sail.
B.5.5. Spinnaker
B.5.5.1. The Area of the Spinnaker shall not exceed 20.00 m2. Spinnaker sail area shall be measured in accordance with the latest ISAF Sail Measurement Calculation
[CPSI = SF * (SL1 +SL2) / 4 + (SMG – SF/2) * (SL1 + SL2)/3]
B.5.5.2. The Half Width of the Spinnaker shall be greater than 75% of the Foot Length (SMG>75%*SF)
B.5.5.3. The distance from the top of the main beam to the highest point to which the spinnaker can be effectively hoisted shall not be greater than 8.60 m.
B.6. Sail Numbers and Class Symbol
B.6.1. The Sail Number, National or Regional letters and Class Emblem shall be placed on both sides of the mainsail at approximately 2/3 of the height of the sail above the boom.
B.6.2. Sail numbers, national or regional letters and class emblem shall sharply contrast in color with the sail
B.6.3. The sail numbers, and national or regional letters shall be placed at different heights on the two sides of the sail, with those on the starboard side being uppermost.
B.6.4. The Class Emblem shall be “18HT“ (double underlined)
B.6.5. Class emblems may be placed at different heights or back to back.
B.6.6. Letters and numbers on the sail shall be at least 300 mm high and 200 mm wide (except for figure 1 and letter l)
B.6.7. Sailmakers’ emblems if any shall be placed within 355 mm of the tack of the sail, and shall not exceed 150 mm x 150 mm.
B.7. Crew Equipment
B.7.1. While racing, the crew shall wear personal buoyancy device
B.7.2. The crew shall not wear or carry clothing or equipment for the purpose of increasing their weight
B.7.3. Trapeze Harnesses shall have positive buoyancy, and shall not weigh more than 2 kg.
B.7.4. A competitor’s clothing and equipment shall not exceed 10kg.
B.7.4.1. Crew Gear and Equipment shall be weighted in accordance with RRS Appendix H.
B.7.5. Each crew may carry up to 2.1 liters (~70 oz) of drinking water in a bladder system worn on their torso. Water bladders for drinking shall be weighed full, and included in the 10Kg limit.
