Tuesday, 6 September 2011

(pillow)Case of the Week (36/11) – 46;

(This is an instalment in a series of blogposts about the ISAF Call book 2009-2012 with amendments for 2010. All calls are official interpretations by the ISAF committees on how the Racing Rules of Sailing should be used or interpreted. The calls are copied from the Call book, only the comments are written by me.)

Case 46

Rule 11, On the Same Tack, Overlapped
Rule 16.1, Changing Course
Rule 17, On the Same Tack; Proper Course
Definitions, Proper Course

A leeward boat is entitled to sail up to her proper course, even when she has established a leeward overlap from clear astern and within two of her hull lengths of the windward boat.
Summary of the Facts
For some time, W had been sailing almost dead downwind on a straight course towards the starboard end of the finishing line when L, a boat that had been clear astern, became overlapped within two of her hull lengths to leeward of W. In the absence of W, L would have sailed a higher course directly towards the line. In order to do so, she hailed W to come up. There was no response. L hailed again and luffed to a position very close to W, but W still did not respond. L stopped luffing and bore away just before contact would have occurred. L protested under rule 11.
The protest committee held that there was insufficient evidence to show that W would have finished sooner by sailing a higher course. It said that even though there might be conflict between the courses of a windward and a leeward boat, a boat overtaking another from clear astern did not have the right to force a windward boat to sail above her proper course.
The protest was dismissed and L appealed, claiming the right to luff up to her proper course under rule 17.
Rule 11 says that when two boats on the same tack are overlapped the windward boat shall keep clear. A leeward boat’s actions, however, are limited by rules 16.1 and 17. There was room for W to keep clear when L luffed, and so L did not break rule 16.1. The protest committee, although it did not say so explicitly, recognized that L’s proper course was directly towards the finishing line. A direct course to the line was not only closer but would also have put both boats on a faster point of sailing. While L was not entitled to sail above her proper course, she was entitled to sail up to it, even though she had established the overlap from clear astern while within two of her hull lengths of W. Accordingly, she did not exceed the limitation to which rule 17 subjected her.

W’s proper course is not relevant to the application of the rules to this incident. She was required to keep clear of L. When L luffed, she gave W room to keep clear as required by rule 16.1. At the moment L needed to stop luffing and bear away to avoid contact, W broke rule 11. Therefore, L’s appeal is upheld and W is disqualified for breaking rule 11.

USSA 1979/224


The fault some sailors make is that a general limitation rule from section B ( rule 14, 15, 16 & 17) is of equal ‘strength’ as (and somehow cancels out) the Right of Way rules from section A. They do not!

The right of way rules do apply, despite the fact that the right of way boat may be ‘restricted’ by one of the rules in section B like in this case, by rule 17.

The keep-clear boat will only not be disqualified if she was ‘COMPELLED” to break a right of way rule (RRS 64.1(c)). In case of rule 17, in a two boat situation, the keep clear boat is never compelled (she wasn’t forced), she can always go up. So even if the right of way boat is sailing above her proper course, the windward boat has no excuse not to keep clear.

Worst case scenario is that both are DSQ-ed. One for 17 and one for 11.


  1. W's sailing makes no sense. She will sail a shorter distance to the finish line by heading up and most boats sail faster reaching than running.

    Sorry, this has nothing to do with the rules...

  2. @ Anonymous
    W wants to make sure that L has no change, not even the slightest one, to finish before him, by steering to the outside finish mark as long as possible.

  3. The scenario might appear contrived but in club racing, the windward/leeward relationship often causes confusion. I think it is a commonly held misconception of the windward boat that if he is sailing a proper course, he does not need to respond to the leeward boat.


  4. @ Wag
    I agree. At that level rule 17 is widely misunderstood.

  5. yeah wag I have to say I agree with you on that point


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