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.2.1. ISAF - International Sailing Federation

A.2.2. MNA - ISAF Member National Authority

A.2.3. ICA - International F18HT Class Association

A.2.4. NCA - National F18HT Class Association

A.2.5. ERS - Equipment Rules of Sailing

A.2.6. RRS - Racing Rules of Sailing

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.4.1. 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.5.1. In the case of doubt, the spirit of the rule shall take precedence over the letter of the rule.

A.6.1. These class rules shall be read in conjunction with the ERS and the RRS. In these Class Rules, Bold Type signifies reference to the ERS

A.7.1. Formula 18HT adopts ISAF Category C
Note: Category C generally permits advertising on hulls, spars and sails without restriction except the space reserved on the sails for: Sail Numbers, National Letters and Class Emblem (See RRS Appendix G); builder’s and sailmaker’s marks not larger than 150mmx150mm each; and the forward 25% of the Hull which is reserved for Event Sponsors and Bow Numbers (See RRS Apendix 1 – ISAF Advertising Code).

A.8.1. These class rules shall not be varied by Notice of race or sailing instructions except as provided by Articles B.3.5.6; B.4.1.4; B.5.3.

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.10.1. Interpretations of these class rules, except as provided by A.10.2{immediately below} shall be made in accordance with ISAF Regulations.

A.10.2. 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.11.1. Sail numbers shall be issued by the ICA

A.11.2. Sail numbers shall be issued in consecutive order starting at "1"

A.12.1. For all boats built after January 1 2004, builders shall be required to pay a fee to the ICA (the Class Fee) before being issued a sail number.

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 classes of builders or levels of production.

A.12.4. The Class Fee may be collected by the MNA on behalf of the ICA.

A.13.1. As of January 1, 2004, all F18HTs 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.13.3. 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.13.4. 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.

B.2.1. The Crew shall consist of 2 persons

B.3.1. Platform

B.3.2. Dimensions

B.3.3. Weight

B.3.4. Corrector Weights

B.3.5. Hull Appendages

B.4.1. Mast

B.4.2. Bowsprit

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. 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. The Mainsail shall be a Soft Sail.

B.5.5. 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.5.6. The Half Width of the Spinnaker shall be greater than 75% of the Foot Length (SMG>75%*SF)

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 sale, with those on the starboard side being uppermost.

B.6.4. The Class Emblem shall be "18HT"

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.7.1. 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.7.5. 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.