Three boats at the leeward mark

General

Firstly, no matter whether this is in the zone or not, when W gybes onto starboard, she gains right of way over both M and L (rule 10).  M, to windward, must also give way to L, to leeward (rule 11), but M, sandwiched between two boats, each of which has right of way, is entitled to room to get out of the sandwich under rule 19.2(b).

When W gybes onto starboard she becomes an obstruction to both M and L (definition of obstruction).  If M and L are overlapped, L must give L room between her and the obstruction (rule 19.2(b).  If M and L are not overlapped, there is no entitlement to room under rule 19.2.

L advanced on M

If L is clear ahead of M, rule 19.2(b) does not apply, but in that case, M does not need L to give room because M can keep clear of W by gybing astern of L.

If L is well advanced on M, but still overlapped, rule 19.2(b) will apply, but it will be a question for the protest committee to decide whether M, to keep clear of W, needed room to be given by L, or whether there was room for M to gybe and keep clear of W, without L doing anything.  If it is necessary for L to give room and she did not do so, L breaks rule 19.2(b) and should be penalised.

Neither L nor M significantly advanced on the other

If neither L nor M is significantly advanced on the other, as long as they are not massively separated, M will need room from L to keep clear of W and if L does not give room she breaks rule 19.2(b) and should be penalised.

M advanced on L

If M is clear ahead of L, rule 19.2(b) does not apply, but M does not need L to give room to gybe away from W, because M is initially right of way (rule 12), then after gybing remains right of way (rule 10), and is not even required to give L room to keep clear under rule 15 because she has not acquired right of way by the gybe.

If M is well advanced on L, but still overlapped, once again the protest committee would need to decide whether there was room for M to gybe away from W without L doing anything, or whether L needed to take some action to give M the room she was entitled to.  If it was necessary for L to take action to give M room and she did not do so she breaks rule 19.2(b) and should be penalised.

Effect of mark-room

Whether boats had reached the zone or not is irrelevant.  Although one or other of L or M would have gained an entitlement to mark-room, this would not affect L’s obligation, if any, to give M room to keep clear of W under rule 19.2(b) (Case 114:  room includes room to keep clear or give room).