When a boat comes abreast of a mark but is outside the zone, and when her
change of course towards the mark results in a boat that is in the zone and
that was previously clear astern becoming overlapped inside her, rule 18.2(a)
requires her to give mark-room to that boat, whether or not her distance from
the mark was caused by giving mark-room to other boats overlapped inside her.
Assumed Facts
Five boats were approaching a leeward mark dead before the wind. Four
of them were overlapped in line with A nearest the mark. The fifth boat,
E, was clear astern of A, B and C when those three boats reached the
zone. When D came abreast of the mark and turned to round it, E became
overlapped inside D. This occurred after E had already reached the zone
and before D reached it. E rounded the mark behind A, B and C but inside
D, which was able to give mark-room to E.
Question
Was E entitled to mark-room under rule 18.2(a) from D?
Answer
Yes.
Because E was clear astern of A, B and C when they reached the zone,
she was required by rule 18.2(b) to give each of them mark-room. Between
E and D, however, a different relationship developed. In order to leave
room for the three inside boats with their booms fully extended, D had
to approach the mark on a course that brought her abreast of it outside
the zone. When E reached the zone, she was clear astern of D and D was
still outside the zone. Therefore, rule 18.2(b) did not apply between
D and E. When D changed course towards the mark, E obtained an inside
overlap and rule 18.2(a) began to apply between D and E. E was entitled
to mark-room under that rule, which D was able to give.