Every boat of a World Sailing Class shall carry on her mainsail and, as provided in rules G1.3(d) and G1.3(e) for letters and numbers only, on her spinnaker and headsail

1. the insignia denoting her class;
2. at all international events, except when the boats are provided to all competitors, national letters denoting her national authority from the table below. For the purposes of this rule, international events are World Sailing events, world and continental championships, and events described as international events in their notices of race and sailing instructions; and
3. a sail number of no more than four digits allotted by her national authority or, when so required by the class rules, by the class association. The four-digit limitation does not apply to classes whose World Sailing membership or recognition took effect before 1 April 1997. Alternatively, if permitted in the class rules, an owner may be allotted a personal sail number by the relevant issuing authority, which may be used on all his boats in that class.

Sails measured before 31 March 1999 shall comply with rule G1.1 or with the rules applicable at the time of measurement.

Class insignia, national letters and sail numbers shall be positioned as follows:

Other boats shall comply with the rules of their national authority or class association in regard to the allotment, carrying and size of insignia, letters and numbers. Such rules shall, when practicable, conform to the above requirements.

When so stated in the notice of race or sailing instructions, a boat chartered or loaned for an event may carry national letters or a sail number in contravention of her class rules.

When a protest committee finds that a boat has broken a rule of this appendix, it shall either warn her and give her time to comply or penalize her.

World Sailing Classes may change the rules of this appendix provided the changes have first been approved by World Sailing.