Monday, 10 March 2014

Back to the Basics (Part 3): Sweet Seventeen

A blog post in a series: Racing Rules for Novices*
(*I'm going to try to do one of these on Mondays)

In this series I would like to give you my insights into those issues in the Racing Rules for Sailing, that nine times out of ten are asked in one of my rules talks, I do for clubs, sailors and/or class organizations, during the winter season.

This weeks issue is about rule 17.
Why is rule 17 so difficult for many sailors? Or  - a better analysis - why is "Hé you, so and so [insert appropriate swearword], sail your proper course" so frequently heard on the racecourse, when it is, even without the swearword, completely inappropriate?

First of all, ask yourself, do I understand what "Proper Course" actually is?
If yes, skip one and go to two. If you're not sure, start with one.

Proper Course is defined in the rulebook.
A course a boat would sail to finish as soon as possible in the absence of the other boats referred to in the rule using the term. A boat has no proper course before her starting signal
"A course a boat would sail to finish as soon as possible...."?

We all know that when you are racing you want to finish as soon as possible - no wait, that's not correct - you want to finish before the other boats do! That means you sometimes want to sail a course that benefits that last goal, but is not the fastest way to finish. If you are the right-of-way boat, you will be able to sail any course you want - provided you don't break a rule. Well, nowhere in the whole rulebook is any rule that states you MUST sail your proper course. So, even when most times, most boats do sail to finish as fast as possible, there's no obligation to do so.

And to make things even more complicated, there might be more than one course that lets you get to the finish faster. Sometimes it is just choosing what you think is best.
There's a patch of wind 50 meters to the left; luff up, go there, and you might gain enough to compensate (and more) for the extra distance you sailed. Than that IS a proper course. As long there is a reasonable assumption that the course you are sailing, might get you to the finish faster, it is - by definition - a proper course.

" absence of the other boats referred to in the rule using that term" ?
Let us have a look at which rules are using the term:
Definition Mark-Room:  The other boat is the boat that must give you that Mark-Room
Rule 17: The other boat is the boat to windward you are making an overlap with.
Rule 18.1(b): The other boat is the boat on the opposite tack.
Rule 18.2(c)(2): The other boat is in fact your boat.
Rule 18.4: The other boats are any other boats. The rule actually has no other boat(s)
Rule 24.2: The other boat is the boat taking a penalty or sailing on another leg.
(there are a couple more in the appendixes, but those you can figure out yourself)

If you encounter a situation with multiple boats, the definition does NOT "take away" all those other boats to determine what the course would have been to finish as soon as possible, only the boats that I indicated in the list with rules.

Lets do an example:
Grey has a rule 17 limitation; Is she sailing above her proper course?
Green is taken out (of the picture). What is the answer now?

Two boats sailing on a beam reach encounter a third who luffs. Grey has a rule 17 limitation. She's shall not sail above her proper course. But because she has to keep clear of Blue, she has to luff and forces Green to go up with her. Now Grey is surely sailing above her proper course! Or is she?
The "other boat" referred to in rule 17 is Green. So take away Green.
Then you are left with Grey and Blue, and in absence of Green, Grey would also have luffed to keep clear. In order to finish as fast as possible (without breaking a rule) she must go up. Therefore she is still sailing her proper course. cah-PEESH?

"... A boat has no proper course before her starting signal"

That, as they say, is more or less self-explanatory. You can't sail a course to finish before the starting signal. Or, any course is good. Even head-to-wind.

So, finally we arrive at


Because most boats want to get to the finish as soon as possible, thinking that that is the whole ballgame - which it is, most of the time, but not always - they assume every other boats must do the same. So when they are held up, usually by a boat that luffs them, or sails a course they don't think is faster to the finish, they get frustrated and start yelling about "proper course".

It is only ever useful, when that other boat has a rule 17 limitation. If that other boat has not, she can sail any course she wants and boats that have to keep clear of her, must keep clear, Regardless if that forces them on a course away from the finish.....
Only a right-of-way boat can HAVE a rule 17 limitation. A keep clear boat never has. And that limitation under rule 17 can only happen to a right-of-way boat, when a set of four conditions are fulfilled. ALL of them. Not one, not two or three, all of them.
Those conditions are:
  • The boats are on the same tack
  • The boat comes from clear astern
  • She makes the overlap to leeward of the other boat
  • The distance between the boats is less than two hull lengths (with two different size boats, the hull length of the leeward boat)
If one of these conditions does not apply, or no longer applies, rule 17 does not apply, or no longer applies. The limitation is lifted, when a boat gybes. It is lifted when the distance becomes more than two hull lengths. It never applies when the overlap is to windward. It never applies when the boat is tacking into that leeward position.... etc. Remember? All of them.


I'm skipping three, four, five all the way to sixteen, so we finally can get to:


Under a rule 17 limitation a right-of-way boat SHALL not sail above her proper course.
(we used to have a rule restricting sailing below a proper course, but those days are over, forget that)

'Above her proper course'.... hmmm....
The keep-clear boat might have another idea about what a proper course is..... well, tough, she's not the one choosing. The right-of-way boat has that privilege.
The keep-clear boat might think the right-of-way boat IS sailing above her proper course. Again, tough luck, it does not mean she no longer has to keep clear.

I'm doing an animation again. In most rule-talks that seems to work best:

Course to the next mark (Finish) is downwind after the mark.
Two boats, approach a windward mark to be left to port, before going downwind toward the finish.

In position 1, Purple on starboard-tack, establishes an overlap from clear astern, with Grey on the same tack. The distance is less than two hull lengths, therefore from that moment on, Purple has a rule 17 limitation. Purple shall not sail above her proper course.

In position 4 Purple luffs head-to-wind. Is she sailing above her proper course?
According to the definition we first must take away the "other boat" mentioned in the rule. That is Grey in this case. Would Purple have headed up, to finish as soon as possible, in the absence of Grey?
Answer is yes, Purple would have done the same. Shooting the mark takes her to the finish sooner.
In position 4 Purple is NOT sailing above her proper course.

Now we look at positions 5 and 6. Is the rule 17 limitation lifted? Or, does one of the conditions no longer apply? Answer is no. She still has a rule 17 limitation.
Next, take away Grey. Would Purple sail the same course, to finish as soon as possible, if Grey was not there? Answer is NO!
Purple would have gone down toward the finish. So in positions 5 and 6 she IS sailing above her proper course and breaks rule 17. Note: Grey is keeping-clear. If she wouldn't, she also would break a rule (rule 11)

Sweet enough for you?

I'm leaving you with some "homework":
Please tell me what Purple has to do, in the same animation, so she can sail this course without breaking rule 17?


Next week: Barging

Previous episodes in this series:
Back to the Basics (Part 2): Where's the referee?

Back to the Basics (Part 1): Keeping Clear


  1. Purple should passes head to wind after pos.4 (in this she must remember about the rule 13) and then return on starboard. Or she should (pausing at position 4) let Grey going in clear ahead.

  2. I'll bite at the question to keep you posting these blogs =). Purple would need to somehow increase the distance between the two boats to more than 2 boat lengths, or slow down and break the overlap.

  3. I can only assume that after the mark there is some obstruction such as a boat or boats that have trawled their spinnakers or broached which means that keeping on a close hauled course until past the obstruction is the fastest course for purple to reach the finishing line

  4. Boris' answer is correct. As soon as Purple passes head to wind in position 4, she is on a different tack and rule 17 switches off. She must keep clear under rule 13, but then she can sail as high as she pleases. I do not think rule 18.3 is broken, as Grey already is sailing higher than close hauled when Purple is changing tack again, but am willing to hear arguments to the contrary....


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