NavList:

The yacht that missed the virtual turning mark (L'Esprit d'Equipe) did so by only about 4 nm.  The mark is at 45 degrees south.  Using the overlay on the tracker to display long/lat, and eyeballing the difference, it looks to be about 4 miles.

Hopefully the penalty, if any, is modest.  4 nm under such circumstances is pretty good work.

There is another possibility.  The GPS position is likely accurate but the chart on which it is displayed may not be.  This is unlikely but make for an interesting anecdote.

In the early days of GPS for recreational sailing we used to have a term - part tongue in cheek but also part serious: Death By GPS.  This refered to a somewhat frequent occurence, whereby a vessel navigating by GPS would run onto a reef, into a rock or some other solid object.  How could GPS be so far out?  Even in the days of selective positioning (meaning the GPS signal was scrambled to limit accuracy to with a wider range that was achievable without scrambling), vessels would steer a "safe" course and still run aground.

Of course the GPS was accurate, or accurate enough.  It was the chart that was wrong.  The reef, rock or other nasty object had its position determined by celestial navigation, bearings from landmarks or a combination of the two.  I remember using paper charts in some locations where at least part of the chart was based on survey/observations that were 200 years old (think in terms of Cook, Vancouver and La Perouse).

Before GPS we knew to give dangerous spots an adequately wide berth.  Some vessels forgot this, or never knew it, depending on the age of the navigator.  In some cases the conequences really were fatal.

Murray B.