Circumnavigation

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To circumnavigate a place, such as an island, a continent, or the Earth, is to travel all the way around it by boat or ship. More recently, the term has also been used to cover aerial round-the-world flights.

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[edit] World circumnavigation

The route of a typical modern sailing circumnavigation, via the Suez Canal and the Panama Canal is shown in red; its antipodes are shown in yellow.
The route of a typical modern sailing circumnavigation, via the Suez Canal and the Panama Canal is shown in red; its antipodes are shown in yellow.

A basic definition of a world circumnavigation would be a route which covers at least a great circle, and in particular one which passes through at least one pair of points antipodal to each other.[1] In practice, different definitions of world circumnavigation are used, in order to accommodate practical constraints depending on the method of circumnavigation.

[edit] Nautical

The map on the right shows, in red, a typical sailing circumnavigation of the world by the trade winds and the Suez and Panama canals; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route roughly approximates a great circle, and passes through two pairs of antipodal points. This is a route followed by many cruising sailors; the use of the trade winds makes it a relatively easy sail, although it passes through a number of zones of calms or light winds.

The route of a typical yacht racing circumnavigation is shown in red; its antipodes are shown in yellow.
The route of a typical yacht racing circumnavigation is shown in red; its antipodes are shown in yellow.

In yacht racing, a round-the-world route approximating a great circle would be quite impractical, particularly in a non-stop race where use of the Panama and Suez Canals would be impossible. Yacht racing therefore defines a world circumnavigation to be a passage of at least 21,600 nautical miles (40,000 km) in length which crosses the equator, crosses every meridian in the same direction and finishes in the same port as it starts.[2] The map on the left shows the route of the Vendée Globe round-the-world race in red; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route does not pass through any pairs of antipodal points. Since the winds in the lower latitudes predominantly blow west-to-east it can be seen that there is an easier route (west-to-east) and a harder route (east-to-west) when circumnavigating by sail; this difficulty is magnified for square-rig vessels..

Since the advent of world cruises in 1922, by Cunard's Lanconia, thousands of people have completed circumnavigations of the globe at a more leisurely pace. Typically, these voyages begin in New York City or Southampton, and proceed westward. Routes vary, either travelling through the Caribbean and then into the Pacific Ocean via the Panama Canal, or around Cape Horn. From there ships usually make their way to Hawaii, the islands of the South Pacific, Australia, New Zealand, then northward to Hong Kong, South East Asia, and India. At that point, again, routes may vary: one way is through the Suez Canal and into the Mediterranean; the other is around the Cape of Good Hope and then up the west coast of Africa. These cruises end in the port where they began.

[edit] Aviation

Aviation records take account of the wind circulation patterns of the world; in particular the jet streams, which circulate in the northern and southern hemispheres without crossing the equator. There is therefore no requirement to cross the equator, or to pass through two antipodal points, in the course of setting a round-the-world aviation record. Thus, for example, Steve Fosset's global circumnavigation by balloon was entirely contained within the southern hemisphere.

For powered aviation, the course of a round-the-world record must start and finish at the same point and cross all meridians; the course must be at least 36,787.559 kilometres (22,858.729 mi) long (which is the length of the Tropic of Cancer). The course must include set control points at latitudes outside the Arctic and Antarctic circles.[3]

In ballooning, which is totally at the mercy of the winds, the requirements are even more relaxed. The course must cross all meridians, and must include a set of checkpoints which are all outside of two circles, chosen by the pilot, having radii of 3,335.85 kilometres (2,072.80 mi) and enclosing the poles (though not necessarily centred on them).[4]

[edit] Surface Travel

There is one successful polar circumnavigation journey; tracing a great circle around the globe 'vertically' i.e. through both poles. Sir Ranulph Fiennes, Charles Burton and their team successfully completed the Transglobe Expedition between 1979 and 1982. Transglobe was the first polar circumnavigation by surface travel, touching two true antipodes: the two poles of the earth. They approximated the great circle passing through Greenwich, covering 52,000 miles in the process. "To the Ends of the Earth" is the classic book which describes this journey.

[edit] Human Powered

To date no one has completed a human powered circumnavigation according to the guidelines set by Guiness World Records.[5]

Colin Angus and Julie Wafaei did complete a circumnavigation of the northern hemisphere, not having crossed the equator, entirely by human power in 2006. National Geographic did recognize this as the first human powered circumnaviation[6] even though Guiness does not.

According to his Expedition 360 website, Jason Lewis is on track to complete the first antipodal circumnavigation by human power, but since his trip has involved non human powered travel between legs it still does not qualify under the Guiness rules as human powered circumnavigation.[7]

[edit] Notable global maritime circumnavigations

[edit] Other notable maritime circumnavigations

[edit] Record maritime circumnavigations

  • Bruno Peyron (French), January–March 2005, fastest circumnavigation 50 days 16 hours 20 minutes 4 seconds.
  • Jean Luc van den Heede (French), 2004, fastest westward single-handed circumnavigation, 122 days 14 hours 3 minutes 49 seconds.
  • Adrienne Cahalan (Australian), February-March 2004, fastest woman to complete a circumnavigation (crew of "Cheyenne") 58 days 9 hours 32 minutes 45 seconds
  • Ellen MacArthur (English), 20042005, fastest single-handed 71 days 14 hours 18 minutes 33 seconds.
  • Jon Sanders holds the world record for completing a single-handed triple circumnavigation.
  • The RMS Queen Mary 2, at 148,528 gross tons, became the world's largest passenger ship to circumnavigate the globe during her 2007 world cruise.

[edit] Notable aerial circumnavigations

[edit] External links

[edit] References