Section 5: Rules of Play

The standard starting sequence uses a 5-minute countdown with visual (flag) and sound (horn) signals: 5 minutes: Warning signal — class flag raised.; 4 minutes: Preparatory signal — flag P, I, Z, or black flag raised (each with different starting penalty implications).; 1 minute: Preparatory flag...

Source: Rule 10, Rule 11, Rule 12, Rule 13, Rule 15, Rule 18

Send this to your friend — argument over.