CALL UMP 24              

11 On the same tack, overlapped
18.2 Passing marks and obstructions - giving room; keeping clear

Question 1
Blue and Yellow are approaching a mark to be left to starboard. Rule 17.1 does not apply to Blue. What is the latest time that Blue may luff?

Answer 1
From the moment that the boats are about to pass the mark, rule 18 begins to apply. From this moment, if Blue luffs and thereafter bears away in order to give Yellow room or to pass the mark, then Blue breaks rule 18. If Blue is able to luff without the need to bear away later, then Yellow is required to keep clear, and rule 11 applies.

Question 2
If Blue will have to bear away to give room, when is she required todo so?

Answer 2
Blue is required to bear away promptly from the moment that the boats are about to pass the mark.