August 2010 - Proper Course III

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August 2010 - Proper Course III

Last month we talked about some rules that use the term proper course. We talked about rule 17, 18.1(b) and “mark-room” used in rule 18.2 and 18.3. This month we will talk about the other two rules that use the term. The first is rule 18.4. 
18.4     Gybing
When an inside overlapped right-of-way boat must gybe at a mark to sail her proper course, until she gybes she shall sail no farther from the mark than needed to sail that course. Rule 18.4 does not apply at a gate mark.

(click on the diagram to see a larger cleaner version)

In the diagram we start with a different situation where rule 18.4 does not apply. The two boats are approaching the weather mark. At position 2 blue establishes an overlap from clear astern to windward. Yellow is the right of way leeward boat (rule 11). She is entitled to mark-room (rule 18.2(b)). She runs rounds the mark and decides not to bear off. No rule requires her to.   Her course at position 7 is probably well above her proper course but she is allowed to sail this course.

(click on the diagram to see a larger cleaner version)

In the second diagram we see two boats approaching a leeward mark on port tack. Orange is clear ahead at position 1. They are overlapped at position 2. Orange is right-of-way leeward boat. She is not limited to sailing her proper course until they enter the zone. At that point, rule 18 and therefore 18.4 start. She is an inside overlapped right-of-way boat who will have to gybe to sail her proper course. She may therefore sail no further from the mark than her proper course. Her proper course may be the wide and close rounding that we see in the diagram. Unlike the previous situation she is not allowed to keep going straight at position 4, even though she is right-of-way and has luffing rights. Once she gybes at position 5 she is no longer subject to this restriction. 

The final rule that talks about proper course is rule 23.2.  This is a rule that rarely comes up except in match racing.
23.2     Except when sailing her proper course, a boat shall not interfere with a boat taking a penalty or sailing on another leg.

(click on the diagram to see a larger cleaner version)

In the diagram as shown Red rounds the windward mark significantly ahead of green and gybes around the mark onto port tack. Green is approaching on the starboard tack layline.   At position 4 as the boats approach each other, green bears away to “attack” red. While green is on starboard tack and therefore right-of-way boat, she is not permitted to do this since she is on a different leg of the course from red and is clearly not sailing her proper course.

One final reminder on a completely different topic since it has come up a few times this summer. A hat is a hat, a shirt is a shirt and a flag is a flag. A red hat (Mount Gay or otherwise) is not a protest flag and will not be accepted as one. 

© Copyright 2010 Andrew Alberti
Posted: 8/1/2010 2:42:45 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 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


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