I was asked two questions this summer from completely different races which both ended up with confusion about which side of the mark to pass.



The first question concerned a windward offset mark. In the diagram, the yellow mark is the windward mark and the red mark is he offset mark. The normal path around this is shown in blue. The boat leaves the yellow windward mark to port and then leave the red offset mark to port. On the leg going towards the windwark mark (often the first leg), the offset mark is not a mark of the course so it can be passed on either side. The green path which leaves the offset mark to starboard on the way up to the windward mark is legal. On the leg after the offset mark the the windward mark is not a mark of the course so the purple course which leaves it to starboard on this leg is also legal. The two red courses each miss a mark so are not legal. That is the easy part. 



In the second diagram, one of the marks has moved (most likely the red one) or they were not laid properly.  If the yellow mark is the windward mark, then the blue course is legal. The red mark has no required side on the leg going towards the yellow mark, so the green course is also legal.  The red course is not legal, since misses the offset mark.

Now what if the red mark was the windward mark and the yellow was the offset.  The blue course is still legal.  It leaves both marks to port at all times.  Whether the boat is passing the red mark on its way up the course or its way back doesn’t matter.  This time however the green course is not legal.  It leaves the red mark to starboard on the windward leg and since the red mark ends that leg, it is not legal.  The red course is now legal since it leaves the red mark to port when it first passes the mark and then the yellow mark to port.  After that the red mark is not a mark of the course so passing it to starboard is also legal.
In the case that actually generated the question, the two marks were the same colour.  There was no way of judging which was which.  The only safe course to take, was the blue course.  The protest committee would have to decide which mark was which and depending which one they chose, one of the other two courses would be illegal. 

This of course raises the question about why the race committee would write sailing instructions using the same colour for both marks.  It turns out that it is much easier to adjust the course for windshifts that way.  We trade off occaisional confusion with out of place marks for frequent correctly set courses. 
 
28 SAILING THE COURSE

28.1 A boat shall start, sail the course described in the sailing instructions and finish. While doing so, she may leave on either side a mark that does not begin, bound or end the leg she is sailing. After finishing she need not cross the finishing line completely.

28.2 A string representing a boat’s track from the time she begins to approach the starting line from its pre-start side to start until she finishes shall, when drawn taut,
(a) pass each mark on the required side and in the correct order,
(b) touch each rounding mark, and
(c) pass between the marks of a gate from the direction of the previous mark.
She may correct any errors to comply with this rule, provided she has not finished.

Next issue I will address the other question.
 
Copies of these rules articles along with animated diagrams can be found at www.rcyc.ca > sailing > Know Your Rules.

© Copyright 2014 Andrew Alberti