At a boat’s preparatory signal, her hull shall be completely outside the line that is at a 90º angle to the starting line through the starting mark at her assigned end. In the pairing list, the boat listed on the left-hand side is assigned the port end and shall display a blue flag at her stern while racing. The other boat is assigned the starboard end and shall display a yellow flag at her stern while racing.
Part appendices
Section C — Match Racing Rules
Match races shall be sailed under The Racing Rules of Sailing as changed by this appendix. Matches shall be umpired unless the notice of race or sailing instructions state otherwise.
Note: A Standard Notice of Race, Standard Sailing Instructions, and Match Racing Rules for Visually Impaired Sailors are available on the World Sailing website.
C4.1