What is A Circumnavigation
- In Practice and in Theory, and Open for Debate

Navigate the Stories

South Africa, December 2012

On the 5th of December 2012 we had crossed all degrees of longitude of the globe, and could perhaps start calling ourselves Circumnavigators. But only in practice, not in theory or officially.

How is that?

Arriving at 025°10' E we had crossed all degrees of longitude (meridians). Are we now circumnavigators. Probably not, but this could be debated.
The red tracks show our progress sofar. The yellow line indicates the distance remaining for a TRUE circumnavigation.

In practice, if a person walks completely around either Pole, they will have crossed all meridians (degrees of longitude), but this is not generally considered a "circumnavigation" (Wikipedia). A circumnavigation should by definition be a route that circles around the entire object, the Earth in our case, and such a route could be called a "Great circle" (I'm cutting a few corners here, and in the following arguments, to make it simpler). All meridians are great circles, but of the parallells only the Equator is a great circle. The legth of the Equator is roughly 40,000 km (21,600 nm), and therefore we can conclude that a circumnavigation of the Earth has to cover at least that distance. However, distance covered is not enough, as is easy to realize. The criteria for a true circumnavigation have been established by several authorities, such as Guinness Book of Records and AdventureStats.com, and they demand the following:

A true circumnavigation of the Earth must: start and finish at the same point, traveling in one general direction, reach two antipodes, cross the equator, cross all longitudes, cover a minimum of 40,000km.

Antipodes are two places on the surface of the globe that are diametrically opposite to each other (and therefore they lie on the same great circle). There are several antipodes along Scorpio's track, but as an example we can mention Gibraltar in the Mediterranean and Whangarei in New Zealand.

So, as a conclusion, we have to admit that even though we now have sailed roughly 70,000 nm on this voyage (which is equal to 3 times around the "world") and crossed all the meridians, we are not theoretically yet circumnavigators. Officially we will not achieve this title until we cross our "outbound" track, which, as it looks right now, will be somewhere close to Trinidad, in May 2013. The strange thing is: if we had gone through the Red Sea two years ago we would have been circumnavigators at the time we would have reached Malta or Sicily, and the required distance for such a track would have been 15,000 nm less than the one we are now attempting.

However, in yacht racing around the world they are not normally circumnavigating either. As you can see in the image on the left below, in a typical yacht racing "circumnavigation", the route does not pass through any pairs of antipodal points, while a typical cruising route indeed does (image to the right).

The route of Vendé Globe, a typical yacht racing circumnavigation,
is shown in red - its antipodes are shown in yellow.
The route of a typical modern sailing circumnavigation
is shown in red; its antipodes are shown in yellow.
Source of images: Wikipedia.com  

Therefore, the World Sailing Speed Record Council (established by the International Sailing Federation, ISAF) has established their own rules for races and speed records, which do not match the one mentioned earlier.

By the way, he first circumnavigators were the 18 survivors of Ferdinand Magellan's expedition (1519-1522), completed by Juan Elcano, after Magellan had lost his life in the Phillipines. The expedition had started with 5 ships and 200 men (Wikipedia). However, it has been argued that Magellan himself actually had circumnavigated at the time of his death, based on knowledge of the locations he had sailed to on previous trips (as he might have been at the meridian of his death several years earlier), and that he therefore himself was the first person to circumnavigate. But the jury is still out on that one.

And for the records: Scorpio was the first pleasure craft, sailing under the Finnish flag, to circumnavigate the world. This occured in 1979-1982, when her name, under previous ownership, was Diana III.

But that is an other story, and it will not be written by me.

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