(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.)
Rule 18.1(a), Mark-Room: When Rule 18 Applies
Rule 64.1(c), Decisions: Penalties and Exoneration
When a boat changes course she may break rule 16, even if
she is sailing her proper course.
S on starboard tack and P on port tack are on a leg from the leeward mark to the finishing line. S has overstood and bears away to clear the stern of the committee boat at the starboard end of the line. P can cross S clear ahead if S maintains that course, and P hails S to hold her course. After S passes the stern of the committee boat, her proper course is to luff to a close-hauled course. S luffs to a close-hauled course at which point there is less than a hull length between S and P. Both then luff to head to wind, and they manage to avoid contact by the narrowest of margins.
What rules govern the relationship between the two boats?
Rule 18 does not apply because the boats are on opposite tacks on a beat to windward (see rule 18.1(a)). Therefore, S is not entitled to mark-room from P. P is subject to rule 10, which requires her to keep clear of S, but rule 16.1 prohibits S from changing course without giving P room to keep clear, even when S is sailing her proper course. In this situation when S luffs to a close-hauled course just after passing the stern of the committee boat, she does not give P room to keep clear and, therefore, breaks rule 16.1. P breaks rule 10, but is compelled to do so because S breaks rule 16.1.
Therefore, P is to be exonerated under rule 64.1(c).
Who initiated the collision course?
That is what I tell sailors when asked about situations like this;
Which boat changed it’s course and created the situation?
If it was the keep clear boat, she in big trouble, she put herself in that position and should keep clear thereafter and if she does not, she breaks a rule of Part 2 section A.
But if it was the right-of-way boat who initiated the collision course, like in this case, she must give room to the keep clear boat to do just that. If the keep clear boat from the moment the collision-course was established, does everything (within a seaman like way) to keep clear, but can not, the r-o-w boat breaks rule 16.1 and then the keep clear boat is exonerated for breaking a rule in Part 2, section A.
If the keep clear boat does not respond, or does not enough or to little, she’s not exonerated and then she still breaks a right of way rule.