January/February 2018 - Now you are at the leeward mark

placeholder image

January/February 2018 - Now you are at the leeward mark

The last two articles looked at boats heading downwind and things to watch out for.  At the end of the leeward leg is the leeward mark.  Many leeward marks these days are gates.  With a gate, boats can choose which of two marks to go around.


In the diagram Red and Green approach the mark on the left side of the diagram (2S) which they will leave to starboard.  Red is on port tack. Green is on starboard tack. Green has forgotten that mark-room applies between boats on opposite tacks as long they are not at the weather mark. We see this by looking at rule 18.1. Rule 18 as a whole is the mark-room rule.  Rule 18.1 describes when the rest of rule 18 applies.  It starts out by saying that it applies between boats that are both required to leave a mark on the same side. All 4 boats in the diagram are required to leave 2S to starboard and 2P to port. It applies when they are both in the zone. From position 2 onwards Red and Green are in the zone.  The rest of rule 18.1 lists exceptions.  18.1(a) and 18.1(b) say that rule 18 does not apply between boats on opposite tacks at a windward mark. In our diagram Red and Green are on opposite tacks but not on a beat to windward so 18.1(a) does not apply. Neither of them will have to tack to sail their proper course at the mark so rule 18.1(b) does not apply. Rule 18.1(c) and 18.1(d) refer to different situations. Since initial part of rule 18.1 applies and the exception do not, mark-room does apply between the two boats. Red is entitled to mark-room and Green has to sail further from the mark to give Red that room. Red is not right-of-way so while she is entitled to room, she cannot just keep sailing straight.  She has to sail around the mark.


On the other side of the diagram Blue and Yellow are also approaching a mark, this time 2P. Yellow is also right-of-way so she does not have to gybe at the mark.  If mark 2P was a standalone mark then yellow would be required by rule 18.4 to gybe. Rule 18.4 however does not apply at gate marks. Blue is in a difficult position.  She would be better to have slowed down and gone behind Yellow or she might have to sail around 2S.



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

  1. between boats on opposite tacks on a beat to windward,

  2. between boats on opposite tacks when the proper course at the mark for one but not both of them is to tack,

  3. between a boat approaching a mark and one leaving it, or

  4. if the mark is a continuing obstruction, in which case rule 19 applies.

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.

© Copyright 2017 Andrew Alberti

Posted: 4/29/2019 11:19:22 AM by Andrew Alberti | with 0 comments

Trackback URL: https://rcyc.ca/trackback/c0289fdd-e2a9-4582-a2a2-16c3c0eacbaa/January_February_2018_-_Now_you_are_at_the_leeward_mark.aspx?culture=en-US

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 2020 are based on the Racing Rules of Sailing 2009-12 or 2013-2016 or 2017-2020 and have not been updated to reflect the changes that apply as of January 2021 with the publication of the Racing Rules of Sailing 2021-24. A copy of the new rules can be found on sailing.org.
Andrew Alberti has been writing these monthly articles in the Kwasind since early 1997.  They explain the Racing Rules of Sailing. Andrew is an International 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 [email protected].


166 Years of Tradition | World-Class Sailing | Toronto Island & City Clubhouse
After You Cross The Finishing Line I
Tacking III
Tacking II
Publication Changes and Tacking
How to Finish
Post Archive
May 2024(0)
May 2024(2)
March 2024(1)
February 2024(1)
May 2023(1)
September 2023(1)
September 2023(0)
May 2023(0)
January 2023(1)
April 2022(1)
December 2021(1)
October 2021(1)
August 2021(2)
March/April 2021(1)
January/February 2021(1)
December 2020(1)
November 2020(1)
September 2020(1)
July 2020(1)
June 2020(1)
May 2020(1)
March/April 2020(1)
January/February 2020(1)
November/December 2019(1)
September/October 2019(1)
July/August 2019(1)
May/June 2019(1)
March/April 2019(1)
January/February 2019(1)
November/December 2018(1)
September/October 2018(1)
July/August 2018(1)
May/June 2018(1)
March/April 2018(1)
January/February 2018(1)
November/December 2017(1)
October 2017(1)
September 2017(1)
August 2017(1)
July 2017(1)
June 2017(1)
May 2017(1)
April 2017(1)
March 2017(1)
January/February 2017(1)
December 2016(1)
November 2016(1)
October 2016(1)
September 2016(1)
August 2016(1)
July 2016(1)
June 2016(1)
May 2016(1)
April 2016(1)
March 2016(1)
January/February 2016(1)
December 2015(1)
November 2015(1)
October 2015(1)
September 2015(1)
August 2015(1)
July 2015(1)
June 2015(1)
May 2015(1)
April 2015(1)
March 2015(1)
January 2015(1)
December 2014(1)
November 2014(1)
October 2014(1)
September 2014(1)
August 2014(1)
July 2014(1)
June 2014(1)
May 2014(1)
April 2014(1)
March 2014(1)
January 2014(1)
December 2013(1)
November 2013(1)
October 2013(1)
September 2013(1)
August 2013(1)
July 2013(1)
June 2013(1)
May 2013(1)
April 2013(1)
March 2013(1)
January 2013(1)
December 2012(1)
November 2012(1)
October 2012(1)
September 2012(1)
August 2012(1)
July 2012(1)
June 2012(1)
May 2012(1)
April 2012(1)
March 2012(1)
February 2012(1)
January 2012(1)
December 2011(1)
November 2011(1)
October 2011(1)
September 2011(1)
August 2011(1)
July 2011(1)
June 2011(1)
May 2011(1)
April 2011(1)
March 2011(1)
February 2011(1)
January 2011(1)
November 2010(1)
October 2010(1)
September 2010(1)
August 2010(1)
July 2010(1)
June 2010(1)
May 2010(1)
April 2010(1)
March 2010(1)
February 2010(1)
January 2010(1)