March 2017 - The 2017 - 2020 Racing Rules Of Sailing II

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March 2017 - The 2017 - 2020 Racing Rules Of Sailing II

This month, we continue with our review of the changes in the latest rule book, 2017-2020. At the time I wrote this, the book was still not available in hardcopy from Sail Canada. It is available on the web from the World Sailing site. This month, I will start to look at mark-rounding.
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.

The space a boat needs in the existing conditions, including space to comply with her obligations under the rules of Part 2 and rule 31, while manoeuvring promptly in a seamanlike way.

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. 

(c) When a boat is required to give mark-room by rule 18.2(b), 

(1) she shall continue to do so even if later an overlap is broken or a new overlap begins; 

(2) if she becomes overlapped inside the boat entitled to mark-room, she shall also give that boat room to sail her proper course while they remain overlapped. 

(d) Rules 18.2(b) and (c) cease to apply when the boat entitled to mark-room has been given that mark-room, or if she passes head to wind or leaves the zone.

(e) If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she did not. 

(f) If a boat obtained an inside overlap from clear astern or by tacking to windward of the other boat and, from the time the overlap began, the outside boat has been unable to give mark-room, she is not required to give it.

The first change is in rule 18.2. A new rule 18.2(d) has been added. This rule describes when the previous two parts – 18.2(b) and 18.2(c) – stop applying. In the diagram, Blue is clear ahead of Yellow when she gets to the zone. According to rule 18.2(b), Yellow must thereafter give her mark-room. How long is “thereafter”? Rule 18.2(d) attempts to answer that question. There seem to be three conditions:

1. when Blue has been given the mark-room;
2. when Blue passes head to wind;
3. when Blue leaves the zone.

The second condition is never met since Blue never passes head to wind. The third condition is met when Blue leaves the zone at position 7. The first condition is the trickiest. If we look at the definition of mark-room it in turn has three parts:

i. room for Blue to leave a mark on the required side;
ii. room to sail to the mark when Blue’s proper course is to sail close to it; and
iii. room to round the mark as necessary for Blue to sail the course.

The first two parts have been met by position 5. The last part is met when Blue gets to the course to the next mark, which is probably between 5 and 6. At this time, she has been given mark-room, so her entitlement to continued mark-room ends. This means that if she gybes onto port at position 6 or later, which is a required part of rounding the mark, she will not be protected by rule 18.

If the course to the next mark were further around, then gybing might perhaps be deemed part of “room to round the mark as necessary to sail the course” and she would still be protected.

The second diagram is at a leeward mark. Green is overlapped inside Red, so Red is required to give Green room. In this case, the course to the next mark is closehauled on starboard. Not understanding the likelihood that Green will tack, Red decides to go fairly wide, trying to go astern and to windward of Green. At position 5, Green heads up to tack. Since this tack is an integral part of rounding the mark to sail the course, she retains her right to mark-room, and until she passes head to wind, nothing in 18.2(d) says that Red can stop giving her room. Once Green passes head to wind, then rule 18.2(d) does say that 18.2(b) has ended and Green is no longer protected. By the time that happens, Red will have had to bear off to avoid hitting Green.

In the more common circumstance, with the next mark directly to windward, tacking is not necessary to “round the mark to sail the course” so Green’s mark-room would probably end just after position 4.

Rule 18.2(e) and 18.2(f) are just the old 18.2(d) and (e) renumbered. There have always been limits on mark-room, but never so explicitly as we see now. If you are in the habit of cutting mark-room fine, either as “giver” or “taker”, do yourself a favour and look closely at the new rules.  

© Copyright 2017 Andrew Alberti
Posted: 3/1/2017 2:02:09 PM 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 on line 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


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