Some participants have to change their sail numbers because of clashes with other participants at the world championship. Before you send emails asking for a number different to the one you have been allocated please recognize the following. The current rules governing sail marks are different to the rules that applied in 2016. So it may not be relevant which numbers were on your sails on the last worlds or the worlds before.

This is an international event and we are bound by the rules. Please read RRS Appendix E
http://sailing.org/documents/racingrules/index.php

• E8 G.1.3 (a) => two digit numbers
• E8 G.1.3 (b) => change on conflict to any number
• E8 G.1.5 (b)(4) => space for a leading "1" is required

An explanation:

The reason to specify a prefix of digit 1 only is that, unless the digits are too narrow to be legible or are placed too close together, it is impossible to fit any other prefix digit in front of the two digit sail number on small sails. There will not normally be room, even on larger sails, for any other prefix if the numbers have been placed in accordance with the pre-2013 and current RRS.

If there are more than two boats with the same sail number, one will sail with that number, one may sail with the prefix 1, and the other(s) will change to other sail number(s). See App E G.1.3 (b). Because the only prefix that is guaranteed to fit is the digit 1 this means that one or more of the two digits will need to be changed to comply with App E G.1.3 (b). However, the chance of this is low.

Apart from reasons associated with sail number legibility there are practical reasons for avoiding unnecessary 3 digit numbers. It helps non-native English speakers (as well as native English speakers) to make protest calls more easily and remember who they have protested more easily. If they are protested or called by an observer or umpire it will be easier for them to understand if it is a two digit number rather than a three digit number.

Furthermore please read the Q&A on the IRSA website carefully to avoid problems during the equipment check.

https://www.radiosailing.org/question-answers/sail-identification