http://www.acronautic.com/antartica-cup-ocean-race/

“The Racetrack outer and inner boundaries are located on latitude 45° South and latitude 60° South making the Racetrack 900 nautical miles wide. The Southern Ocean officially starts below latitude 60° South (International Hydrographic Organisation (IHO) www.iho.shom.fr/ . Latitude 60° South is also the border of the Antarctic Treaty Organisation www.antarctica.ac.uk/aboutantarctica/treaty”

Here are my calculations: in the globe earth model;

S45 latitude would give a circle of 2π * 6371km * cos 45°= 28300km = 17600 miles,

S60 latitude would give a circle of 2π * 6371km * cos 60°= 20000km = 12400 miles.

In the flat earth model;

S45 latitude would give a circle of 2π² * 6371km * (180°-45°)/180° = 94308km = 58600 miles,

S60 latitude would give a circle of 2π² * 6371km * (180°-30°)/180° = 105000km = 65000 miles.

“Konyukhov came through it all unscathed, returning to King George Sound at 02: 56:50 UTC (10:56:50 WST) to record a time of 102 days 00 hours 56 minutes 50secs for this 16,400 mile circuit of Antarctica.”

The race data clearly proves a globe earth.