April 2016 - Answers To Questions – Different Proper Course II

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April 2016 - Answers To Questions – Different Proper Course II

In the January/February issue my article showed the diagram below.  I received some new questions based on the diagram.  

Click Image for larger animation

In the diagram, Blue is sailing directly downwind with a symmetrical spinnaker. Blue is being overtaken to leeward by Yellow, who as is typical for a boat with an asymmetrical spinnaker, is sailing higher than would be sailed by a boat with a symmetrical spinnaker or white sails. The person asking the question asked what happens if Blue had been on starboard tack all along. That of course changes the situation completely and it is a very good question. At position 1, in the diagram as shown, Blue is right-of-way because the boats are on the same tack and Yellow is clear astern of Blue, so rule 12 applies. If Blue were on starboard tack, then the boats are on opposite tacks and rule 10 applies, so Blue has right-of-way. At position 2 in the diagram the boats are on the same tack and overlapped, so according to rule 11, Yellow has right-of-way. If Blue were on starboard, then rule 10 still applies and Blue has right-of-way. If you are going to sail directly downwind, it is much safer to be on starboard tack.

The second part of the question that I was sent was “if Blue is not on starboard at position 1, does it have the option to gybe over to starboard before Yellow reaches position 2 and establishes an overlap?” If just after position 1, Blue gybes onto starboard, then she goes from right-of-way under rule 12 to right-of-way under rule 10. The right-of-way never changes. (Match racers beware - this is not true in match racing, since rule 13.2 would apply in the middle - I won’t cover that here, but you have been warned!) If she never alters course, neither rule 15 nor rule 16 apply and Yellow must keep clear of Blue.  

Click Image for larger animation

If we stretch the question a little further, as shown in the second diagram, and Blue gybes after the overlap has been established, we have different question.  At position 1, Blue has right-of-way.  At position 2, Yellow has right-of-way.  At position 3, Blue has right-of-way.  Blue has gained right-of-way through her own actions so rule 15 applies.  She has to initially give Yellow room to keep clear.  As long as she does so, she is okay and Yellow must keep clear.  If her gybe is so close to Yellow that Yellow cannot keep clear, then Blue has gybed too close and broken rule 15. The lesson here is to gybe while there is still space. 
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.

When a boat acquires right of way, she shall initially give the other boat room to keep clear, unless she acquires right of way because of the other boat’s actions.

© Copyright 2016 Andrew Alberti
Posted: 4/1/2016 1:18:04 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 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 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 kyrules@alberti.ca.


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