Team Race - CALL A 06   

Rule 10 On Opposite Tacks
Rule 11 On the Same Tack, Overlapped
Rule 18.1 Rounding and Passing Marks and Obstructions: When this Rule Applies
Rule 18.2 Rounding and Passing Marks and Obstructions: Giving Room; Keeping Clear

Question 1
Boats A and X are on converging courses approaching a starboard-hand leeward mark. At what point are they about to pass the mark so that rule 18 starts to apply?

Answer 1
When A reaches the two-length zone the boats are definitely 'about to pass' the mark, and in most circumstances two lengths is an acceptable measure of 'about to pass'. If conditions are windy and boats need to start preparing to pass the mark when farther from the mark, they become 'about to pass' when they need to start preparing.
[See also ISAF Cases 84 and 94.]

Question 2
A and X are approaching the same mark. A has established a windward overlap from clear astern, so rule 17.1 does not apply. What is the latest time X may luff, and, if X will have to bear away to give room, when is she required to do so?

Answer 2
Rule 18 starts to apply when the boats become about to pass the mark. If X has to bear away to give A room to pass the mark, she must do so promptly when rule 18 starts to apply. From this moment, if X luffs and thereafter bears away in order to give A room to pass the mark, she breaks rule 18.2(a). If X is able to luff without the need to bear away later then A is required to keep clear, rule 11 applies.

When a boat is within the two-length zone (and not sailing away from the mark), she is 'about to pass' the mark. In windy conditions, in a strong favourable current, when spinnakers must be dropped, or when several boats are close to one another, a boat may be 'about to pass' when she is farther than two lengths from the mark.