Rules Brainteaser

[Diva27]

I just did what I should have a while ago, and consulted the USCG nav rules. Here are the pertinent regs with respect to sailing craft. I'm right in general about port-starboard and windward-leeward, but others are right about "overtaking keeping clear" when any vessel is astern of another, even if one is power and the overtaking one is sail. A sailboat approaching a powerboat or another sailboat from anything more than 22.5 degrees aft of the beam has to keep clear. Overtaking rules trumps.

Rule 11

Rules in this section apply to vessels in sight of one another.

Rule 12

(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:

1. 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;
2. 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;
3. 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.

RULE 13
OVERTAKING

(a) Notwithstanding anything contained in the Rules [of Part B, Sections I and II / 4 through 18], any vessel overtaking any other shall keep out of the way of the vessel being overtaken.

(b) A vessel shall be deemed to be overtaking when coming up with a another vessel from a direction more than 22.5 degrees abaft her beam, that is, in such a position with reference to the vessel she is overtaking, that at night she would be able to see only the sternlight of that vessel but neither of her sidelights.

(c) When a vessel is in any doubt as to whether she is overtaking another, she shall assume that this is the case and act accordingly.

(d) Any subsequent alteration of the bearing between the two vessels shall not make the overtaking vessel a crossing vessel within the meaning of these Rules or relieve her of the duty of keeping clear of the overtaken vessel until she is finally past and clear.

[tap]

Originally Posted by Diva27

(a) When two sailing vessels are approaching one another

Perhaps most relevant to the original question, these rules are for two vessels, not three. With three vessels it's possible for each vessel to be both give-way and stand-on. How can you both hold your course and make a significant change in course?

Originally Posted by Diva27

With sailboats, the concept of overtaking keeping clear applies to boats on the same tack, not opposite tacks.

Depends on the rules, this is where the colregs and the racing rules of sailing differ. In the colregs, overtaking trumps port-starboard. In the RRS, rule 12 (overtaking) only applies to boats on the same tack, and so rule 10 (port-starboard) has higher priority.

[philsboat]

When I'm out pleasure sailing I go out of my way to prevent any kind of situation like that from getting to the point where I have to make that decision.A tack or a course change are much easier on the nerves and makes for friendlier day on the water.But.....when it comes to racing I want my rights if it helps my race!

Phil

[KurtV]

This kind of situation is often referred to as "special circumstances". The term comes from Rule 2 and is generally taken to mean that when more than two vessels are approaching each other so as to involve risk of collision ALL of them are required to keep out of the way of the others.

If you get caught in one of these situtions you should act early and act in a way that's readily apparent to the other vessels.

[Diva27]

Originally Posted by KurtV

This kind of situation is often referred to as "special circumstances". The term comes from Rule 2 and is generally taken to mean that when more than two vessels are approaching each other so as to involve risk of collision ALL of them are required to keep out of the way of the others.

If you get caught in one of these situtions you should act early and act in a way that's readily apparent to the other vessels.

You've hit the nail on the head. Be alert, act early, don't get to the point where three people on three boats who don't know each other (and aren't talking) suddenly have to make simultaneous perfect responses. I'm sure I'm not unique, but I boat in an area where the first four miles away from dock is a mess of upbound and downbound traffic and channels crossing. We call the main crossing point "the washing machine" because of all the cross-chop wake. Tour boats, freighters, every imaginable size of powerboat and jet-ski, sailboats large and small, under sail and under power (and some you're not sure which). Anticipate, anticipate, anticipate.