You could finish the Vendee Globe or Golden Globe 2018 races and never circumnavigate the globe. This is the dirty little secret of both of these grueling round the world races.
The often forgotten requirement of a circumnavigation is that you need to travel to opposite sides of the earth to complete one. How can you determine what is your antipode which is the opposite side of the earth as defined by a line through your position and the center of the earth?
It is easy. Here is how you do it:
- The latitude of the antipode is the your latitude in the other hemisphere. For example, if you are at 30 degrees North latitude, your antipode is at 30 degrees south latitude. Alternatively, if you are at 10 degrees South latitude then your antipode is at 10 degrees North latitude.
- The longitude of the antipode is takes a little calculation. Subtract your east or west longitude from 180 and your antipode will be that number in the opposite hemisphere.
When longitude is expressed in fractions the simple calculation in step 2 is the simplest. Otherwise, with minutes and or seconds of longitude you have to remember the 60 minutes = 1 degree of longitude and 60 seconds = 1 minute of longitude.
Our video found that the round the world races of the Vendee Globe and the 2018 Golden Globe Race don’t require that finishers circumnavigate the globe. That is because you need to go as far north as you go south to hit an antipode. The farthest north point on the course is Les Sabes D’Lonne, France, 46°29′50″N 1°47′00″W, that has an antipode just east of the south island of New Zealand which the participants sail under. Thus, if a competitor in those races sails far under New Zealand or does not dip south to sail under New Zealand then there is an excellent chance they will never hit an antipode pair in their 30,000 nm trip. Thus, you could finish the Vendee Globe or Golden Globe 2018 races and never circumnavigate the globe. That is a pity. The original 1968 Golden Globe was much more likely to require finishers to circumnavigate the earth because it left from England which is roughly at the same longitude as Les Sabes D’Lonne, France but farther north.
The GGR 2018 retro sailing race requires competitors to stop in Hobart, Australia for its “film drop.” That is about 43S and 147E. The Hobart antipode is 43N and 33W. Then they must pass under the south island of New Zealand and north of Snares Island at about 48S and 166.5E. The opposite side of the earth from Snares Island is 48N and 13.5W approximately. Both Jean Luc Van Den Heede, first place in the GGR, and his closest competitor Mark Slats are east of 33W approaching Les Sabes D’Lonne, France (46.5N and 2W approximately) but well south of 43S, the southernmost point of that line of antipodes. Only if Slats moves well north of his great circle route to the finish will he ever hit an antipode. Jean Luc Van Den Heede crossed an antipodal pair just east of New Zealand and near the Les Sables D’Lonne start. Second place Mark Slats sailed too far south after passing New Zealand to hit an antipode at the start. On January 19, 2019, Slats was at about 33N and 27W. He had less than 1,400 nm to finish at 16:00 UTC on January 19, 2019.
Below are the commonly requirements of a circumnavigation.
A circumnavigation of the Earth must:
1. start and finish at the same point
2. travel in one general direction
3. reach two antipodes
4. cross the equator
5. cross all longitudes
6. exceed the circumference of the earth at the equator of 21,600 nm
Note that the antipode rule (#3) guarantees that #4 and #6, you cross the equator and your journey exceeds the circumference of the earth at the equator, are satisfied. Thus, crossing the equator and travelling over 21,600 nm are necessary, but not sufficient conditions for a circumnavigation or reaching an antipode in science speak. The antipode rule requires that you travel to the opposite side of the earth and back, which means that you traveled a distance greater than the equator and touched the equator on your journey.
Capt. Linus Wilson, is the author of How to Sail Around the World Part-Time. The Slow Boat has only traveled across 83 degrees of longitude since 2016, and no antipodes have been reached in that time.
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