December 2020 - Proper Course – an over-used term

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December 2020 - Proper Course – an over-used term

Before we discuss this further, I should explain what “proper course” means. The Rules define proper course as the course that you would sail to finish as soon as possible if the other boat involved in the rule wasn’t there. It does not mean the course that you would sail if no other boats were there. For example, if the rule in question is rule 17 and you are the leeward boat, then it is the course that you would sail if the windward boat was not there. 

In the first diagram in position 1, Yellow is clear astern of Blue. Yellow gradually establishes an overlap to leeward and within two hull lengths of Blue. This is exactly the situation described in rule 17, so Yellow is not allowed to sail above her proper course, which would be the course that Yellow would sail if Blue was not there. As Yellow looks ahead though, she sees two smaller boats, Red and Green, who have capsized, attended by  a safety boat. Yellow decides to sail above them to avoid them, and as this is what she would do to finish as quickly as possible in the absence of Blue, this is Yellow’s proper course. Although this course forces Blue to luff slightly as well, Yellow breaks no rule as this is now her quickest course to the next mark and thus her proper course. You will notice that neither we nor the rule ever talked about Blue’s proper course, as in this situation, Yellow has a proper course in respect of Blue, but Blue is not constrained or advantaged by a proper course in respect of Yellow. Simply, Blue must stay clear of Yellow.


So when does a boat have to sail her proper course? The short answer is never. I have gone through the Racing Rules of Sailing to see all of the references to proper course (outside the appendices which apply to Boards, Match Racing, Team Racing etc.). There are not very many, but I have listed them all with this article.

  • We have already discussed the definition of “proper course”.
  • The definition of Mark-Room mentions proper course, but only to note which boats are entitled to room to sail to the mark.
  • Rule 17 says that certain leeward boats may not sail above their proper course.  They are allowed to sail below their proper course.
  • Rule 18.1 just uses the term to help define when mark-room applies. Rule 18.2(c)(2) says that if a boat has to give mark-room, but ends up overlapped on the inside, they have to give the other boat room to sail her proper course.  The other boat doesn’t have to sail her proper course, but that is all the room the now- inside boat must give her. Rule 18.4 says that at a leeward mark, if the proper course for the inside right-of-way boat is to gybe, then she can’t sail further from the mark than her proper course.  She can still sail closer; she just can’t sail further.
  • Finally rule 24.2 (23.2 in the 2021-2024 rules) says that if reasonably possible, a boat should not interfere with certain other boats such as boats on another leg and boats taking a penalty unless the first boat is sailing her proper course.


Several boats therefore have restrictions related to proper course, mainly in rule 17, 18.4 and 24.2, but those restrictions usually allow a course alteration in another direction.  If you are an Opti sailor sailing in the Green Fleet in Hamilton and you see your mother watching from the lawn, there is no rule (other than the post-race wrath of the coach) that prevents you from sailing towards shore to wave. If you are sailing along and you see a spectator boat with some attractive crew, there are no rules that prevent you from sailing towards them. If you are a leeward boat and a boat comes up from astern and tries to pass you to windward there is no rule that prevents you from luffing them up in an effort to persuade them to pass you to leeward next time.


This is the last issue for the year. There will be a new rule book taking effect January 1, 2021.  I will start my next article with a review of the rule changes. For those of you who want to look ahead, go to  for a full copy of the rules.  There is also a study edition with all of the changes marked and the submissions that led to those changes.  Dave Perry has put together a great summary of the changes.  You can find it in various places on the web including here.

Speaking of Dave Perry, Dave has posted a mini-webinar on the US Sailing website, specifically on Rule 17 and proper course.  Go to and scroll down to the bottom of the page.



Mark-Room   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.

Proper Course A course a boat would sail to finish as soon as possible in the absence of the other boats referred to in the rule using the term. A boat has no proper course before her starting signal.


If a boat clear astern becomes overlapped within two of her hull lengths to leeward of a boat on the same tack, she shall not sail above her proper course while they remain on the same tack and overlapped within that distance, unless in doing so she promptly sails astern of the other boat. This rule does not apply if the overlap begins while the windward boat is required by rule 13 to keep clear.

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.

(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.

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.

24.2    If reasonably possible, a boat shall not interfere with a boat that is taking a penalty, sailing on another leg or subject to rule 22.1. However, after the starting signal this rule does not apply when the boat is sailing her proper course.

Posted: 12/9/2020 8:24:54 PM by Andrew Alberti | with 0 comments

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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
December 2020 - Proper Course – an over-used term
November 2020 - Further down the line at the start
September 2020 - Back to the Usual Start
July 2020 - An Unusual Start II
June 2020 - An Unusual Start
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