Q&A 2013.017 B005 describes a situation where a boat enters the zone clear ahead, but does not have the right to room to gybe after she has rounded the mark as necessary to sail the course. This appears to be linked to the fact that the boat clear astern remains clear astern during the rounding manoeuvre.

Question 1

Assume the situation started up the same way, but the boat clear astern established an inside overlap after the boats had entered the zone and while the other boat was entitled to mark-room. If gybing round the mark was a proper course for the boat clear ahead at the zone, would she now have the right to room to gybe under rule 18.2(c)(2) provided both boats remained inside the zone and overlapped?

Answer 1

Yes. As the inside overlap was obtained before mark-room had been given, the boat required to give mark-room must additionally give the other boat room to sail her proper course while they remain overlapped. Providing the boat entitled to mark-room is sailing her proper course, she is sailing within the room to which she is entitled by rule 18.2(c)(2) and will be exonerated under rule 21(a) for breaking rule 10.
 

This obligation to give room to sail a proper course, and the related exoneration, will continue to apply until either the overlap is broken or the boat entitled to mark-room leaves the zone.
 

Would the answer be the same if, when the overlap was established, the boat entitled to mark-room had already been given mark-room?

Answer 2

No. If the boat had been given mark-room when the overlap was established, rule 18.2(c)(2) would not apply.
 

Whilst rule 18 would continue to apply as long as at least one of the boats is still in the zone and the rule has not been switched off, no part of rule 18.2 places any obligations on any boat. This is because rule 18.2(c)(2) specifically states that the circumstances have to be met 'when' there is an existing requirement on a boat to give mark-room. Once mark-room has been given, no such requirement exists. Therefore, the boat that was clear ahead is no longer entitled to room or markroom,

rule 21 no longer applies, and the boat that entered the zone clear ahead is governed by the rules of Section A. See also Q&A .
 

Question 3

Are there other circumstances where a boat gybing to port tack in front of a boat on starboard tack can rely on exoneration under rule 21 if she breaks rule 10, and if so, under what circumstances?
 

Answer 3

Rule 21 only addresses situations governed by the rules of Section C. There may be situations at continuing obstructions where the boat clear ahead will need room to gybe, in which case rule 21 may also apply.