The right-of-way rules that govern mark rounding seem to be changed with every new book.  There is a continuing effort to simplify these rules, which fights against the complexity forced by the large number of different situations that can occur at marks.  I am going to try to explain the new rule.  I believe in almost every example that I give the eventual outcome is exactly the same as in the last rule book.  I am going to start with one of the definitions.

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 then
(b) room to sail her proper course while at round the mark as necessary to sail the course.

However, mark-room does not include room for a boat to tack unless the boat she is overlapped inside and to windward and on the inside of the boat required to give her mark-room and she would be fetching after her tack.

Since the marked up version is confusing here is the complete new definition:

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 does not include room for a boat to tack unless she is overlapped inside and to windward of the boat required to give her mark-room and she would be fetching the mark after her tack.
 
Here is the complete old definition:

Mark-Room
Room for a boat to sail to the mark, and then room to sail her proper course while at the mark. However, mark-room does not include room to tack unless the boat is overlapped to windward and on the inside of the boat required to give mark-room.
Rule 21 is a new rule which replaces rule 18.5 and 20.2.  We will look at the changes later in the year.

21 EXONERATION
When a boat is sailing within the room or mark-room to which she is entitled under a rule of Section C, she shall be exonerated if, in an incident with a boat required to give her that room or mark-room, (a) she breaks a rule of Section A, rule 15 or rule 16, or
(b) she is compelled to break rule 31.

Arthur Wullschleger (known to everyone as Tuna) was one of the original match race umpires.  He served on International Juries and umpired all over the world.  He helped us with regattas in Toronto many times and provided wonderful guidance to many of today’s umpires in North America.  He passed away late last year.  The first time you stepped on to an umpire boat with Tuna, he told you that there were only two types of boats in the world, “right-of-way boats” and “give-way boats”.


(click on the diagram to see a larger cleaner version)
 
When boats approach marks the same distinction applies.  Some boats claiming mark-room are right-of-way boats, others are not. In the first part of the diagram, we see the Yellow and Blue boats approach a windward mark on starboard tack.  The Yellow boat is the leeward boat; she is the right-of-way boat so her behaviour is relatively unconstrained.  She is also the inside boat, so she is entitled to mark-room (according to rule 18.2 which we will cover later).  We can see at position 4 that she luffs Blue, taking much more room than is needed to round the mark, but her right-of-way status allows her to do this.

On the other hand, as the Red and Green boats are approaching the leeward mark the Red boat is the give-way boat since she is the windward boat. Once she enters the zone, Red earns the right to mark-room. Red’s proper course is to sail around this mark, so when Red and Green get to the zone (just after position 1), Green has to give Red room to sail to the mark.  She cannot head up and squeeze Red out, and when they get to the mark, Green has to give Red room to sail around the mark. Red uses mark-room to allow her to break the windward-leeward right-of-way rule (rule 11) and rule 20 “exonerates her” for breaking it. The definition is written, though, to place limits on how much room she may take.  At position 4, she has room to round the mark but not as much room as she might have liked to sail “wide and close”.  If she sailed further from the mark, she would have taken more room than required and would not be exonerated.  Yellow is able to sail a wider course since she is right-of-way, while Red can only take the room that is absolutely necessary.



Some of the new words “when her proper course is to sail close to it” can be explained in the second diagram.  The Orange boat is ahead clear ahead when she gets to the three-hull-length zone. She is entitled to mark-room.  Her proper course, however, is probably to sail directly to the finishing line. She cannot claim room to sail directly to the mark.

Note: The article above was corrected on July 16, 2013. The original referred to blue and yellow being on port tack.
 
© Copyright 2013 Andrew Alberti