Monday, 26 December 2011

(pillow)Case of the week (51/11) – 30

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

(pillow)Case picture


Rule 14, Avoiding Contact
Rule 19, Room to Pass an Obstruction
Rule 64.1(c), Decisions: Penalties and Exoneration
Definitions, Keep Clear

A boat clear astern that is required to keep clear but collides with the boat clear ahead breaks the right-of-way rule that was applicable before the collision occurred. A boat that loses right of way by unintentionally changing tack is nevertheless required to keep clear.



Summary of the Facts

Boats A and B were running on starboard tack close to the shore against a strong ebb tide in a Force 3 breeze. A was not more than half a hull length clear ahead of B. B blanketed A, causing A to gybe unintentionally. This was immediately followed by a collision, although without damage or injury, and B protested A under rule 10. The facts were agreed, and both boats were disqualified: B under rule 12 because she was too close to A to be keeping clear, and A under rule 10 for failing to keep clear of a starboard-tack boat.

A appealed on the grounds that she was compelled by B’s action to break rule 10. The protest committee, commenting on the appeal, stated that B caused both A’s gybe and the collision by not keeping clear when both boats were on the same tack.


The boats were passing close to the shoreline, which was an obstruction and also a continuing obstruction. Therefore, the conditions for rule 19 to apply were met. However, because the boats were not overlapped, neither of the two parts of rule 19 that place an obligation on a boat (rules 19.2(b) and 19.2(c)) applied. When B was clear astern of A she was required by rule 12 to keep clear but failed to do so. Her breach occurred before the collision, at the moment when A first needed ‘to take avoiding action’ (see the definition Keep Clear). When B collided with A she also broke rule 14.

However, at that time she held right of way under rule 10, so is not subject to penalty under rule 14 because there was no damage or injury. After gybing, A became the keep-clear boat under rule 10, even though she had not intended to gybe. She broke that rule, but only because B’s breach of rule 12 made it impossible for A to keep clear. A did not break rule 14 because it was not ‘reasonably possible’ for her to avoid contact.

Accordingly, B was properly disqualified by the protest committee under rule 12. However, A is exonerated under rule 64.1(c) for her breach of rule 10. A’s appeal is upheld, and she is to be reinstated.

RYA 1974/3


In this post rule 19 has no effect although it applies. I’ve drafted another post from one of the ESS acts where it does. Come back tomorrow and read about it.

The conclusion that A is to be exonerated can only be reached if you write down the facts found in chronological order. Then it becomes clear that the infringement of rule 12 by boat B already occurred before rule 10 came into play.

Nevertheless I can understand the PC that made this mistake. They could not use rule 15 because boat A gybed and therefore boat B acquired row because of the other boat’s actions.


  1. This case frustrates me because the decision does not answer the questions as clearly as it could. As I understand it, the decision would be the same if A had gybed intentionally at a time when gybing would immediately break rule 10 ---so long as there was a purpose for gybe consistent with good sportsmanship, such as avoiding the shore or avoiding collision with B.

    If I understand the logic correctly, the summary could be: A boat that is required to keep clear breaks the right-of-way rule that applies the moment she first fails to keep clear.

  2. @OHara
    I agree with your summary.
    But if boat A intentionally gybes, an argument could be made that she contributed to the contact and broke rule 14.


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