On Starboard or Port Tack?

[seadago]

Originally Posted by Adelie

I believe the OP was asking for the purpose of determining what the boat’s status was under the COLREGS which is a legal question.
Legally a sailing vessel has to be on one tack or another.

I agree! Was being facetious. But given the ambiguity in the rules, the real problem of who's supposed to stay the course and who should adjust remains. Does the wind rule apply if he tack can't be determined? This is a real-time decision for both skippers.

[Adelie]

There is no ambiguity in the rule. The whole text reads:

“Rule 12 - Sailing Vessels Return to the top of the page

(a) When two sailing vessels are approaching one another, so as to involve risk of collision, one of them shall keep out of the way of the other as follows:

(i) when each has the wind on a different side, the vessel which has the wind on the port side shall keep out of the way of the other;
(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 starboard 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 that on which the mainsail is carried or, in the case of a square-rigged vessel, the side opposite to that on which the largest fore-and-aft sail is carried.”