At first, Red and Green were clear astern and had to keep clear of Blue. When
Blue slowed down by rolling, she became windward boat and had to keep clear
in accordance with rule 11. Because it was her own action that changed the right
of way, Blue had to keep clear at the moment the overlap began without protection
from rule 15 (see last sentence
in rule 15). Red and Green had
to take avoiding action before Blue's masthead was in the water. Therefore Blue
has infringed rule 11 and will be penalized. After Blue has capsized (masthead
is in the water - see rule 23) Red and Green keept
clear. Red's fouling of Green was forced by Blue's infringement of rule
11 and Red will be exonerated under rule 64.1(a).