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.
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