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Notes from the Mac #2 - Section Breaks: Hidden Secrets Exposed!

June 25, 2018 01:37 PM

Don’t let the title fool you, there is nothing clandestine about how the Mac Committee places boats into Sections.  Setting Section breaks is not an exact science and there are many ways to approach it.  We want to explain the logic behind how section breaks in the Mac are established.

We try to make all sections roughly the same size.  For the 44 cruising boats and 153 monohull racing boats racing in non-One Design sections, we attempt to group boats into Sections of about 15 boats, largely based on their ORR handicap rating. This allows boats to race against boats of roughly similar speeds but puts enough boats in a Section that there is decent competition.  But how do we place boats into their specific Sections?

After setting our rough goal of 15 boats, section:


  1. First, we sort all non-One-Design boats by their ORR All-Purpose ratings (fastest to slowest), keeping the Cruising and Racing Divisions separate.   Having a clean descending list of boats with corresponding ratings is the great way to start.
  2. Next, we work from the top down (fastest to slowest) and then the bottom up (slowest to fastest) to draw initial break lines so each Section averages about 15 boats.
  3. Here is where it starts to get a little tricky. Near the break lines, we look for boats that might be a "better fit" in the adjacent Section.  In this step, we make every effort try to keep natural competitors together without creating too large of a rating spread within a section. This step is all about a balancing act because although it’s nice to see your friendly Wednesday Night and weekend rivals on the starting line it’s also important to minimize the corrected time difference between the fastest and slowest boat within any given Section.
  4. Another little trick that we use to tighten the corrected time difference within a Section is to use a "natural" rating break.   This occurs when there is a significant rating gap where no boats rate. If that gap falls near one of our initial break lines we try to put the Section break in the middle of that gap so we effectively tighten the rating spreads in the two Sections that fall on either side of the break line.
  5. Lastly, when a boat is on the bubble between Sections, we use the Mac Offwind rating as a sanity check to make sure we place the boat in the appropriate Section.


There you have it!  As you can see, there is a mix of science and art to group boats racing under ORR into fair & fun Sections, providing the best competitive racing we can within each section.


As a reminder, section breaks are already posted.  You can find the preliminary section breaks on the Mac site by section, or you can see all boats in the division. Note that these are preliminary and subject to change before the Race. If you have any questions you can always contact the CYC Regatta Manager.




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