P is sailing up-river, close-hauled on port tack, very close to the bank. S, unable to point as high as P, is forced to sail away from the bank. She then tacks onto starboard and immediately hails "Starboard" to P. P sails on and, when she reaches a position at which she cannot luff without hitting the bank or bear away without colliding with S, she hails S for room.

Question

Which rule or rules apply?

P is subject to rule 10 and must keep clear. P is also required by rule 14 to avoid contact if reasonably possible. S establishes right of way over P when she tacks onto starboard, but must observe rules 13 and 15. S meets rule 13's requirement by not tacking so close that P has to take avoiding action before S reaches her close-hauled course. After S acquires right of way over P under rule 10, S complies with rule 15 by initially giving P room to keep clear.

Rule 19.2(b) does not apply because S and P are on opposite tacks, are not both sailing more than 90 degrees from the true wind, and so are not overlapped at positions 3 and 4 (see the last sentence of the definition Clear Astern and Clear Ahead; Overlap). Rule 20 does not apply because P and S are not on the same tack. Therefore, S is not required to give P room in response to P's hail for room. However, after it becomes clear that P is not keeping clear, rule 14 requires S, if it is reasonably possible, to avoid contact with P. S would risk disqualification if there were contact that caused damage or injury.

GBR 1978/5