January 29, 2012

When to give way

HERE'S A REQUEST for help from a sailor in Juneau, Alaska.  "Last summer we were sailing on port tack when we spotted another sailboat way up to windward of us," says Northern Alex. "The only sail he had up was a spinnaker, and it was obvious from our angles of approach that if we each held our course we would be in a collision situation.  In a situation like this, how do you tell who has right of way?"

Okay Alex, I see your problem.  If you're both on the same tack, the windward boat should keep clear of the leeward vessel.  But if you're on opposite tacks, and he's on starboard, you have to keep clear of him.  And the trouble is, you can't tell if he's on port or starboard.

So let's go back and start from the beginning.  Here are my usual steps:

1. Try to ascertain if he's under power as well as sail.  If he is, he should be exhibiting a black cone, point down, in the bow.  Most amateur sailors ignore this rule, so check for exhaust smoke or engine cooling water instead.

ØIf he's under power (even if he has sails up) he must keep clear of you.

2. If it's another sailboat under sail only, check which tack he's on.

Ø If he's on the opposite tack to you it's simple: port tack gives way to starboard tack.

Ø If he's on the same tack, the windward boat must keep out of the way of the leeward boat.

3. But here's the interesting bit:

Ø If you're on port tack, and you see a sailing vessel to windward and cannot determine with certainty whether the windward vessel has the wind on the port side or the starboard side, you shall keep out of the way of the windward vessel.

The rule doesn't address what happens if the situation becomes clearer to you at the last minute, and you suddenly decide that he is the one who should be keeping clear. But common sense should tell you that if you've already made an obvious move to keep clear of  him, he will expect you to follow through and not create a last-minute emergency.

But the question remains: How were you to know what tack he was on, when he was flying only a spinnaker?

Well, the rules define the windward side as the side opposite that on which the mainsail is carried, OR the side opposite to that on which the largest fore-and-aft sail is carried.

Thus, Alex, your situation was certainly ambiguous, since no mainsail was being carried by the windward boat.  If the spinnaker was boomed out to port, I would say that the mainsail, if it were being flown, would be deployed to starboard. That would put the windward boat on port tack and he'd have to keep out of your way. 

If a boomless cruising spinnaker were being flown from the starboard side, I'd say the boat was on port tack and the same situation would apply.

Nevertheless, if there's any doubt in your mind about any of this, you must revert to the rule under 3 above.  Play it safe. Presume he is the stand-on vessel and that you should keep out of his way.  Then make an large and obvious course correction so that he, too, knows what's in your mind.

Today's Thought
If a man will begin with certainties, he will end with doubts; but if he will be content to begin with doubts, he shall end in certainties.
— Bacon, Advancement of Learning

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3 comments:

Roger Jones said...

John:

I agree with your analysis. However, I have a couple of rules that I go by recognizing that they can, if not carefully followed, cause even more problems. I should point out that I am a single hand ocean cruiser so major sail changes can take some time.

1) The law of gross tonnage: If I see a big ship and I can't contact it on the radio I will try to avoid it. Many cruise ships for some reason think they have the absolute right of way. With an active AIS on board the "I didn't see you" excuse is somewhat more lame, but I would rather be wrong and alive then right and run down.
2) The "whats he flying and what am I flying" and the "is he racing" rule. If I am more maneuverable, for example under jib and main, I will avoid people flying symmetric spinnakers just because its easier for me to get out of the way. By the same token I try to avoid a race course or if I have to pass through it do so in a manner not impede the racing boats.

On the down side I know quite a few people who have the attitude when running under sail and power that it only takes one second (the one before a collision) to turn off the engine and change the rules.

Thanks again for a great blog.

mgtdOcean said...

That's a nice write up John, but unless I'm in an organized race, I just assume that the other sailboat has no idea what the rules are and if they don't steer clear when appropriate I get out of the way. I've even run across "ghost" sailboats on port tacks in the Cheaspeake Bay, they sail by with no one in sight and don't respond to any calls. Guess the sun got to then and they needed a nap:0

And forget about power boats giving way, they generally don't seem to have any situational awareness. I think that some motorboats think it's funny to roll that little sailboat from the actions I've observed.

I never seen the inverted cone and I'm also guilty but next season the cone will be used. I do fly the anchor ball and have had boaters come over and ask what that was:)

Anonymous said...

Two items
-just because an engine is running does not mean the vessel is under power. The rules state that the vessel has to be using propelling machinery, ie: transmission engaged.
-totally agree when in doubt get out of the way with a large conspicous action that can be observed by the other vessel.