Page 106 - Collision Avoidance Rules Guide

(ii) when both have the wind on the same side, the vessel
which is to windward shall keep out of the way of the
vessel which is to leeward;
(iii) If a vessel with the wind on the port side sees a vessel to
windward and cannot determine with certainty whether
the other vessel has the wind on the port or on the star-
board side, she shall keep out of the way of the other.
(b) For the purposes of this Rule the windward side shall be
deemed to be the side opposite to that on which the mainsail is
carried or, in the case of a square-rigged vessel, the side oppo-
site to that on which the largest fore-and-aft sail is carried.

COMMENT:
Paragraph (a)(iii) has been added to bring this Rule into line with the
International Yacht Racing Rules. The remaining paragraphs are
identical with Rule 17 of the 1960 Regulations.
Rules 8, 13, 16 and 17(a), (b) and (d) also apply when two sailing
vessels are approaching one another so as to involve risk of collision.
A sailing vessel must take early and substantial action to achieve a
safe passing distance. The other vessel must initially try to keep her
course and speed, but wind changes may make this difficult.
Rule I2 will not apply if one of the vessels under sail is also using
propelling machinery as such a vessel is considered to be a power-
driven vessel.

Exceptions
A sailing vessel approaching another sailing vessel from a direction
more than 22.5" abaft her beam is an overtaking vessel and must keep
clear regardless of wind direction, as Rule 13 over-rides Rule 12. A
sailing vessel must also keep out of the way of any sailing vessel
which is engaged in fishing, or not under command, and showing the
appropriate lights or shapes.

Ambiguous case
Paragraph (a)@) covers the ambiguous case in which a sailing vessel
with the wind on the port side sees the green sidelight of another sail-
ing vessel to windward at night and is unable to determine whether
the other vessel has the wind on the same side and is required to keep

87