May 2015 - How The Main Right Of Way Rules Relate To Each Other

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May 2015 - How The Main Right Of Way Rules Relate To Each Other

Sometimes I find that people know the primary right of way rules (port-starboard, windward-leeward and overtaking boat keep clear), but they are not clear on how the rules relate to each other. I was recently asked a question about a port-tack leeward boat on a close-hauled course and a starboard-tack windward boat sailing downwind.

About 13 years ago in this series, I introduced a very simple flowchart. Some people like flowcharts, some don’t, but this one is simple and does clarify decision-making. The point of the chart is to demonstrate that the rules in Part 2 refer to specific conditions or states, with respect either to one of the boats (“Is one boat tacking?”) or to the relationship between them (“Are the boats overlapped?”). Identifying these basic states and organizing them in their order of precedence clarifies which rule applies as the boats meet.

 Each of the rules in Section A of Part 2 starts with “When” or “After” which begins a phrase that describes when the rule applies. Rule 13 describes “After a boat passes head to wind” “until she is on a close-hauled course”. If this situation applies then rule 13 applies and 10, 11 and 12 do not. Rule 10 talks about boats on opposite tacks. If the boats are on the same tack, it does not apply. Rule 11 and 12 only talk about boats on the same tack. If the boats are on opposite tacks, they do not apply. Finally, rule 11 talks about overlapped boats and rule 12 talks about boats that are not overlapped. To decide which rule applies we ask a series of questions in order.

1. Has the one of the boats passed head to wind and not yet obtained a close-hauled course. If yes, rule 13 applies.

2. Are the boats on opposite tacks? If yes, rule 10 applies. If not, either rule 11 or 12 applies.

3. If the boats are on the same tack, are they overlapped? If yes, rule 11 applies. If not, rule 12 applies.

When boats are on opposite tacks, a port-tack boat shall keep clear of a starboard-tack boat.

When boats are on the same tack and overlapped, a windward boat shall keep clear of a leeward boat.

When boats are on the same tack and not overlapped, a boat clear astern shall keep clear of a boat clear ahead.

After a boat passes head to wind, she shall keep clear of other boats until she is on a close-hauled course. During that time rules 10, 11 and 12 do not apply. If two boats are subject to this rule at the same time, the one on the other’s port side or the one astern shall keep clear.

In the diagram we started with, neither boat has passed head to wind, so rule 13 does not apply. The boats are on opposite tacks so rule 10 does apply and rule 11 and 12 do not. Since rule 10 applies, the port tack boat (Red) has to keep clear of the starboard tack boat (Green).
Copies of these rules articles along with animated diagrams can be found at > sailing > Know Your Rules.

© Copyright 2015 Andrew Alberti
Posted: 5/1/2015 12:19:13 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 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
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


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