August 2014 - Opposite Tacks At The Finishing Line

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August 2014 - Opposite Tacks At The Finishing Line

After this year’s RCYC Open, I was asked some questions about finishing. I can’t comment on exactly what happened since I wasn’t there and I haven’t heard any related protests. I can comment on how the rules apply to the situations, as described by the people who asked me the questions.

The first situation shows two boats approaching the finishing line near the committee-boat end. Blue is on port tack. Yellow is on starboard tack. When Blue gets to the three-length zone around the finish boat, the two boats are overlapped. The race committee boat is a finishing mark and the two boats are required to leave it on the same side so, according to rule 18.1, rule 18 applies. Rule 18.2(b) says that Yellow as the outside boat has to give the Blue inside boat mark-room. Mark-room is defined as the room to sail to the mark. Blue cannot continue on her original reaching course but Yellow has to alter her course to give Blue room to sail to the mark and room to round the mark. Blue on port tack does not keep clear of Yellow on starboard tack but she is exonerated for breaking rule 10 (a rule of Section A) according to rule 19. In simple terms, mark-room does apply at finishes and it can override the port/starboard rule.

18.1 When Rule 18 Applies
Rule 18 applies between boats when they are required to leave a mark on the same side and at least one of them is in the zone.

However, it does not apply
(a) between boats on opposite tacks on a beat to windward,
(b) between boats on opposite tacks when the proper course at the mark for one but not both of them is to tack,
(c) between a boat approaching a mark and one leaving it, or
(d) if the mark is a continuing obstruction, in which case rule 19 applies.

18.2 Giving Mark-Room
(a) When boats are overlapped the outside boat shall give the inside boat mark-room, unless rule 18.2(b) applies.
(b) If boats are overlapped when the first of them reaches the zone, the outside boat at that moment shall thereafter give the inside boat mark-room. If a boat is clear ahead when she reaches the zone, the boat clear astern at that moment shall thereafter give her mark-room.

When a boat is sailing within the room or mark-room to which she is entitled under a rule of Section C, she shall be exonerated if, in an incident with a boat required to give her that room or mark-room,
(a) she breaks a rule of Section A, rule 15 or rule 16, or
(b) she is compelled to break rule 31.

Room for a boat to leave a mark on the required side. Also,
(a) room to sail to the mark when her proper course is to sail close to it, and
(b) room to round the mark as necessary to sail the course.
However, mark-room for a boat does not include room to tack unless she is overlapped inside and to windward of the boat required to give mark-room and she would be fetching the mark after her tack.

In the next diagram, another two boats are approaching the finish with Red on port tack and Green on starboard tack. This time they are far enough away from the mark that Red can alter course to avoid Green and still have room to pass the mark. If Red had held her course at position 3, she would not have been keeping clear of Green. She would not be sailing within the mark-room to which she was entitled, so she would not be exonerated for breaking rule 10. Again in simple terms, while mark-room applies at the finish, it only overrides the port/starboard rule if you are close to a mark and entitled to mark-room.

© Copyright 2014 Andrew Alberti
Posted: 8/1/2014 10:57:41 AM by Andrew Alberti

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This page provides links to a set of articles original published in Kwasind magazine. The versions here include animated diagrams. The original articles can be found within the original magazines which are available online back to January 2007. 

Articles before December 2016 are based on the Racing Rules of Sailing 2009-12 or 2013-2016 and have not been updated to reflect the changes that apply as of January 2017 with the publication of the Racing Rules of Sailing 2017-20. A copy of the new rules can be found on
Andrew Alberti has been writing these monthly articles in the Kwasind since early 1997.  They explain the Racing Rules of Sailing. Andrew is a National Judge and National Umpire. He is a member of the Sail Canada Rules and Appeals Committees. The interpretation of the rules contained in the articles is Andrew's and not that of the RCYC or any of the committees he sits on. 

Send your questions to Andrew at


166 Years of Tradition | World-Class Sailing | Toronto Island & City Clubhouse
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