Monday, 16 January 2012

(pillow)Case of the week (03/12) – 27

(This is an instalment in a series of blogposts about the ISAF Case book 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 2, Fair Sailing
Rule 14, Avoiding Contact
Rule 15, Acquiring Right of Way

A boat is not required to anticipate that another boat will break a rule. When a boat acquires right of way as a result of her own actions, the other boat is entitled to room to keep clear.

Summary of the Facts

AS was clear ahead of BP when she reached the zone. Between position 1 and 2, AS, a hull length to leeward and a hull length ahead of BP, tacked as soon as she reached the starboard-tack lay line. Almost immediately she was hit and damaged by BP travelling at about ten knots. The protest committee disqualified AS for breaking rule 15. It also disqualified BP under rule 2, pointing out that she knew AS was going to tack but did nothing to avoid a collision. BP appealed, asserting that she was not obligated to anticipate an illegal tack.


BP’s appeal is upheld. She is to be reinstated.
After AS reached the zone, BP was required to keep clear of AS and give her mark-room under rule 18.2(b). Both these obligations ended when AS passed head to wind because the boats were then on opposite tacks and on a beat to windward. When AS passed through head to wind, BP became the right-of-way boat under rule 13 and held right of way until AS assumed a close-hauled course on starboard tack. At that moment AS, having just acquired right of way under rule 10, was required by rule 15 to give BP room to keep clear. BP took no action to avoid a collision, but what could she have done? Given her speed and the distance involved, she had perhaps one to two seconds to decide what to do and then do it.

It is a long-established principle of the right-of-way rules, as stated in rule 15, that a boat that becomes obligated to keep clear by an action of another boat is entitled to sufficient time for response. Also, while it was obvious that AS would have to tack to round the mark, BP was under no obligation to anticipate that AS would break rule 15, or indeed any other rule. BP broke neither rule 2 nor rule 14.

 USSA 1971/140


There are many cases in the casebook that are ‘important’. But, in my opinion, together with Case 50, this case is about a fundamental principle.

The rules don’t demand anticipation. You don’t have to think about what another boat is going to do. You only have to react to what a boat is actually doing. (There’s an exception in rule 18, but I’m going into that, at this moment)

In his Case boat BP had only a few seconds to avoid AS, after AS completed her tack. Although it was obvious that AS wanted to tack to round the mark, she had to, besides judging the room she needed to complete her tack, also to take in consideration the time and space BP would need to keep clear, once she was on starboard. Rule 15 is written to point to that fundamental principle.

One boat length to leeward and one boat length ahead is not enough distance to tack in front. In Match Racing the Umpires would conclude that there was not enough room to tack and therefore BP was in a controlling position.


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