22.12 Sailing vessels
Maritime Rules Part 22: Collision Prevention
(1) For the purpose of rule 22.12 the windward side is defined as—
(a) in the case of a square-rigged vessel, the side opposite to that on which the largest fore and aft sail is carried; or
(b) in any other case, the side opposite to that on which the mainsail is carried.
(2) When two sailing vessels are approaching one another so as to involve risk of collision, one must keep out of the way of the other as follows—
(a) when each has the wind on a different side, the vessel which has the wind on the port side must keep out of the way of the other;
(b) when both have the wind on the same side, the vessel which is to windward must keep out of the way of the vessel which is to leeward;
(c) 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 starboard side, it must keep out of the way of the other.
(3) Sailing vessels when operating propelling machinery must obey the rules for a power-driven vessel.