October 10, 2016

Knowing when to give way

EVERY NOW AND THEN we come across a situation under sail where someone has to give way to someone else, but nobody really knows who has to do what.

Imagine, for example, if you are sailing on port tack when you spot another sailboat way up to windward. The only sail he has up is a spinnaker, and it’s obvious from your angles of approach that if you each hold your course you will be in a collision situation.  In a situation like this, how do you tell who has right of way?

The rules say that 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.

Ø If 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 that on which the largest fore-and-aft sail is carried.

But this situation is ambiguous, since no mainsail is 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

Tailpiece

"Wanna lift home? I like giving rides to experienced girls."

"But I'm not experienced."

"You're not home yet."

2 comments:

Anonymous said...

John,

Have been reading your blog for a long time. Unfortunately, given the recent media focus on certain issues, I think your 'Tailpiece' is in extremely poor taste... makes me sad that you would even post something like this under the circumstances...

Edward Jones said...

When not racing, I just assume the other boater doesn't know the rules and I've never been disappointed. I also always apply the rule of gross tonnage.