Flag C with repetitive sounds at the rounding mark or gate, with the new bearing, a green triangle (change to starboard) or red rectangle (to port), or a minus or plus for a shorter or longer leg. The signal must be made before each boat begins the leg; the new mark need not be in place yet. Subsequent legs may be changed without further signals to keep the course shape.
RRS 2025–2028 · Part 3
33 Changing the Next Leg of the Course
The race committee may change the next leg by moving the next mark or the finishing line, signalled before boats begin the leg.