How Did Bouvet Island Get Lost 271 Years Ago ?

[shamrock838]

How Did Bouvet I. Get Lost 271 Years Ago?:

In August 1738, the French explorer Jean Baptiste de Lozier Bouvet set out to find a reported “land of princes and parrots” called “Terra Australis Incognita” for the French East India Company.

Instead, on January 1, 1739, he happened across a barren, ice-covered landfall in the furthest reaches of the fearsome Southern Ocean that was named after him. It proved to be the most isolated speck of dry land on the face of the earth.

Using the unreliable tools of the day for determining longitude, Bouvet plotted the island’s longitude 200 miles west of its present-day position (54o 26' South Lat by 3o 24' East Long). How could this have happened?

One source says that Bouvet based his questionable longitude calculation, not on the Prime Meridian (0º) at Greenwich, but by the longitude of Praia, capital of the Cape Verde Islands (14º 55’ N by 23º 31’ W) – 375 miles off the west coast of Africa.

Could this have accounted, at least in part, for Bouvet’s error 271 years ago? Any additional theories?

Thanks,

[hummingway]

It seems a very plausible theory. According to one book I read on Capt. Cook, longitudinal calculations were not very reliable since the calculation was based on time and the basis for the correct relative time was a moving target. A common way to find something was to sail to the correct latitude and sail a course along the lat until running into the place you were looking for. Bouvet did better then C. Columbus who went to his grave convinced he had sailed to India, China and Japan when in fact he'd only managed some islands in the Carribean!

[Pyrate]

Longitude was not easy to figure out back then. It was essentially based off of dead reconing. Not until John Harrison developed his marine chronometers did figuring out longitude become reliable at sea. If I remember correctly, this was in the 1750-1760s. Therefore, on a long ocean voyage, finding an uninhabited island and plotting it within 200 miles of its actual position with no other references is not too bad.

[micah719]

So how did he actually determine his longitude? Lunar distance method?

[S/V Alchemy]

More likely DR since his last known longitude, which very well might have been Cape Verde or perhaps Cape of Good Hope. Lunars were difficult to calculate and accurate timekeeping was not yet possible, so most skippers would use DR and "latitude running" until they hit something familiar.

Clearly, on a voyage of discovery, this had its shortcomings.

[jackdale]

Originally Posted by S/V Alchemy

More likely DR since his last known longitude, which very well might have been Cape Verde or perhaps Cape of Good Hope. Lunars were difficult to calculate and accurate timekeeping was not yet possible, so most skippers would use DR and "latitude running" until they hit something familiar.

Clearly, on a voyage of discovery, this had its shortcomings.

And that is exactly how Columbus did it; DR and a quadrant.

The world (literally) owes James Harrison much more than he received grudgingly from the Royal Society.

[S/V Alchemy]

Having read the book and seen the documentary (with dramatic parts) based upon Harrison's often frustrating efforts to get his rightful recognition, I entirely concur.

His achievement is as if there was only one Wright Brother, who built a flying plane in 1903, and was told to come back time and time again with improved models until he could produce a working jet fighter in 1945, all while competitors were free to steal and backward engineer his ideas and the notion of "patent" was weak and issued more or less at whim.

Captain Cook had nothing but praise for his chronometers, and if Cook liked it, it was probably excellent kit!