Match races are umpired unless the notice of race or sailing instructions say otherwise. World Sailing also publishes a standard notice of race and standard sailing instructions for match racing, and match racing rules for visually impaired sailors.
Key points
C2 Rule changes on the water
The duel format rewrites much of Part 2. The zone is two hull lengths, rule 13 also covers gybing, rule 17 is deleted, rule 18 is rewritten, arm signals accompany hails for room to tack, a boat finishes only after completing her penalties, and the race committee may move a starting mark only until the warning signal. A new rule 7 tells umpires to assume nothing has changed until they are sure it has (last point of certainty).
C3 Signals and starting
Matches have their own sequence: flag F as an attention signal, a numeral pennant as the warning signal, P as the preparatory signal, and a blue or yellow flag marking the end of the pre-start entry period. Each boat then enters from her assigned end (rule C4).
C4 Requirements before the start
Each boat is assigned an end: the first-named boat in the pairing takes the port end and flies a blue flag, the other the starboard end with a yellow flag. At the preparatory signal a boat must be outside a line square to the starting line through her end's mark, and within the next two minutes she must cross the starting line from the course side to the pre-start side.
C6 Protests by boats
For a Part 2 incident she was involved in (other than rule 14), a boat protests by showing flag Y immediately; the umpires answer on the water with a green and white flag for no penalty or a penalty signal. Protests under other rules use a red flag and are reported after finishing; no written protest is needed. Rule 31 and rule 42 are left to the umpires.
C7 Penalty system
Rule 44 is deleted. A penalized boat may delay her penalty within limits and takes it by gybing and luffing to close-hauled on an upwind leg, or tacking and bearing away on a downwind leg.
C8 Umpire-initiated penalties
Umpires may penalize without a protest for certain breaches, including gaining an advantage after taking a penalty, and may end a match when one boat retires after both have started.
C10 Scoring
One point to the winner of each match (half each for a dead heat). Incomplete round robins are scored by average points per match; incomplete multiple round robins share one point per pairing. Knockout series need the stated number of wins.
C11 Ties
Round-robin ties go to head-to-head results, the last match between two tied competitors, results against the highest-placed competitors, and so on; knockout ties to the most recent round robin and the most recent match. Remaining ties may be sailed off.