Blue shall be penalized. When Red reaches the zone
she is clear ahead. According
to rule 12 Blue shall keep
clear and according to rule 18.2(b) give mark-room
to Red. After getting a leeward overlap Blue shall give still room mark-room
to Red according to rule 18.2(c). Red is breaking rule 11. Because Reds proper
course is close to the mark, she is sailing within the mark-room,
she is entitled, and therefore she is exonerated by rule 21. Blue shall be penalized for breaking rule 18.2(b).