Graphic animations

In my post Baker 2012, I left the analysis until a future posting, hoping that there would be some comments with analyses.  The expected comments came in (both on the blog and by e-mail), and I discovered a problem with the description of the incident: the animated graphical display was misleading.

An animated graphical display is better than the traditional static display for several reasons.  First, it shows much more clearly what happened throughout the incident.  If you’ve ever analyzed a US Appeal, ISAF Case, or match- or team-race Call, you’ve probably been frustrated by the fact that a key part of the rules discussion hinges on a circumstance that happened between positions n and n+1.  Because the critical fact isn’t shown, we are forced to guess what happened, and when.  Second, the animated graphical display moves the boats in realistic ways, whereas the static display may actually put the boats in positions that it’s impossible to get into, in subtle ways that make a difference in how the scenario plays out.  In fact, even if you use Boat Scenario (http://boats.sf.net) or TSS (http://tss.peronneau.net) only to build static diagrams, I urge you to run your diagrams through the animation feature, just to pick up the places where, if your static diagrams were true, boats would cross through each other or jump from place to place without changing course. 

But an animated graphic can also misrepresent the scenario in a way that the static display (or an on-the-water umpire’s view) doesn’t do, and that’s the case with the graphic in ‘Baker 2012’.  In that animation, when A luffs X, X clearly leaves the zone, so she loses her rights to mark-room.  But when she jibes back and enters the zone, she’s still clear ahead of the third boat, B.  You can see this clearly if you look at the static display that remains for a second or two after the animation concludes – at position 5, a line drawn across X’s stern crosses at least ½ boatlength in front of B.

My original description of the scenario stated that X was clear ahead of B when she re-entered the zone, but somehow that sentence got dropped when I was reformatting the blog.  My apologies.

In any case, please take a second look at the Baker 2012 post and tell me now what you think.

What's a 'black and white flag'?

The pre-2013 team race rules (Racing Rules of Sailing (RRS) Appendix D) allowed umpires to display a black flag if they wanted to hold a hearing after the race.  Two examples of when they might do this are if there might be damage from contact, or if a team gains an advantage from a foul (think about an illegal mark trap where the boat that gains from the trap doesn't break any rule, so the umps can't make her spin to remove the advantage).  The problem with using a black flag for this purpose is that, to the uninitiated, it looks as if some drastic penalty were being administered -- after all, in match racing a black flag ends the race and awards it to the other boat. 

The pre-2013 Appendix D also allowed the umpires to display either a green flag or green-and-white flag to indicate "no penalty".  The problem with an all-green flag is that sailors who are red/green colorblind can't tell it from a red flag, which of course means the exact opposite of a green one.

Appendix D of the 2013-2016 Racing Rules of Sailing solves these problems by changing the black flag to a "black and white" flag, and requiring a "green and white" flag for "no penalty".  This, of course, poses the question of exactly what green-and-white and black-and-white flags might look like.

Appendix C for Match Racing has always specified a green-and-white flag signifying "no penalty", and most event organizers meet that requirement with something like this:

So I figured, we could just use the same checkered pattern for black and white flags.  But Richard Thompson, the chairman of the Appendix D Working Party, set me straight.  He points out that in dim light green and black might not be easily distinguishable, so we need another pattern.  He suggests something diagonal: 

Richard points out that any distinctive pattern would do -- maybe a skull and crossbones?  I agree such a flag would satisfy the rule and distinguish itself from the green-and-white flag, but I prefer Richard's diagonals. 

So, before January 1, 2013, when the new RRS take effect, we should go to the local sailmaker (or flagmaker) to get a new set of diagonal black-and-white flags -- or add a diagonal white stripe to the flags we already have.

Baker 2012

Here’s a situation that came up at the 2012 Baker Trophy – the US High-School Team Race Championship.  It was at the leeward mark (Mark 3) of a digital-N course; the next leg was a beam reach toward Mark 4.

Boat A came into the zone at the leeward mark in first place, overlapped inside X and clear ahead of the rest of the fleet.  A, who had luffing rights, luffed X to the edge of the zone.  The plan was to hold X out until B arrived, but X was able to slow enough to jibe astern of A and turn back toward the mark.  A jibed with her and sailed straight to the mark. 

Meanwhile, B had sailed toward the mark, fully expecting that A would be able to hold X away long enough for B to round in first place.  Caught by surprise when this didn’t happen, she failed to react quickly enough and ended up caught on starboard tack at the mark, with no mark-room.  So she decided to make the best of a bad situation and jibe inside X and A, hitting X and the mark. 

Imagine you’re an umpire and you manage to see all this correctly.  What is your call?  I’ll give you a little time to come up with your answer (though of course if you were actually an umpire you would have no time), and publish my answer in the next posting.