April 2015 - Three Boats At The Leeward Mark

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April 2015 - Three Boats At The Leeward Mark

Last month, I talked about three boats at a windward mark. This month I would like to look at three boats at a leeward mark.



I will start with a two-boat situation. Blue and Yellow are approaching a leeward mark on port tack. When Blue gets to the three-length zone, Yellow is overlapped on the inside. According to rule 18.2(b), Yellow is entitled to mark-room and Blue gives it to her – simple and straightforward.
 
18.2 Giving Mark-Room
 (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.

Clear Astern and Clear Ahead; Overlap One boat is clear astern of another when her hull and equipment in normal position are behind a line abeam from the aftermost point of the other boat’s hull and equipment in normal position. The other boat is clear ahead. They overlap when neither is clear astern. However, they also overlap when a boat between them overlaps both. These terms always apply to boats on the same tack. They do not apply to boats on opposite tacks unless rule 18 applies or both boats are sailing more than ninety degrees from the true wind.

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. 

Room
The space a boat needs in the existing conditions, including space to comply with her obligations under the rules of Part 2 and rule 31, while manoeuvring promptly in a seamanlike way.



In the second diagram, we find a very similar situation, but with three boats. All three are approaching the mark on port tack. Green is outside Blue who is outside Yellow. As Green and Blue get to the three-length zone, they are clearly overlapped and Yellow is overlapped inside Blue. Is Yellow overlapped with Green? If we look at the meaning of overlap (a defined term), Yellow is overlapped with Blue and Blue is overlapped with Green so Blue, who is a boat between Blue and Yellow, overlaps them both – therefore Green and Yellow are overlapped. Since they are overlapped, Green has to give mark-room to Blue and Yellow. Blue also has to give mark-room to Yellow.

How much room does Green have to give Blue? At first glance, it might appear that Green is being over-generous – although the rule only states that Green needs allow Blue room to round the mark as necessary to sail the course, Green is also giving Blue room to sail wide enough to allow mark-room to Yellow. Green, however, knows that her obligation doesn’t stop at giving Blue room to sail the course, as the definition of mark-room rests on the defined term “room”. This definition of “room” includes “space to comply with her obligations under the rules of Part 2”. Rule 18.2, like all of the right-of-way rules, is a rule of Part 2. Blue is obligated under rule 18.2 to give Yellow mark-room, so Green must allow sufficient room for Blue to give mark-room to Yellow.

Copies of these rules articles along with animated diagrams can be found at www.rcyc.ca > sailing > Know Your Rules.

© Copyright 2015 Andrew Alberti
Posted: 4/1/2015 12:15:40 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.
ABOUT ANDREW ALBERTI
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. 

QUESTIONS & ANSWERS
Send your questions to Andrew at kyrules@alberti.ca.

 

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