CALL UMP 22              

Rule 18.1, Mark-Room: When Rule 18 Applies
Rule 18.2(b), Giving Mark-Room

Question 1
Blue and Yellow approach the windward mark on port tack with Blue clear ahead at the zone. The mark is to be rounded to starboard. Blue immediately gybes onto starboard tack. There is a Y flag. What should the call be?

Answer 1
Rule 18.2(b) requires Yellow togive Blue mark-room. Gybing while rounding the mark is a proper course for Blue, so if in the judgment of the umpires her gybe was part of her mark rounding, Yellow must give Blue room to gybe. Display the green and white flag.

Question 2
How far past the mark may Blue sail, gybe and remain protected?

Answer 2
As long as Yellow is still passing the mark, 18.2(c) continues to apply and Blue remains protected. The use of 'boats' and 'they' (plural) in rule 18.1 means that rule 18 continues to apply until both boats have passed the mark.