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Captain Jorge Juan - International Spy in the Age of Sail

In April 1748, the long War of Austrian Succession came to an end, leaving the Spanish Navy in a terrible plight. Spain was dependent for her financial survival on the flow of bullion from her American possessions, but her navy had proven incapable of protecting this vital life-line. Her treasure fleets had been captured by the Royal Navy, her warships defeated and vital bases in South America like Portobello had fallen. The coming of peace was acknowledged by all as only a temporary respite between the competing European powers all of which left Spain’s talented Minister of War, the Marques de la Ensenada brooding over his country’s problems. He knew that Spain needed to rebuild its navy, but how could this best be achieved? As the Britain seemed to be the emerging naval power of the age, eclipsing the Dutch and French, he concluded that it would be prudent to learn from them. Time for a little espionage.

The chief spy he selected to send was an inspired choice. The thirty-five year old Jorge Juan y Santacilia was one of two naval officers who had been sent a decade earlier to Peru as part of a scientific expedition. In the high Andes they had carried out ground-breaking astrological work to calculate the true shape of the earth. Having successfully proven that it was not perfectly round, but flat at the poles, Juan returned to Spain where he published Relacion del viaje a America, a strikingly insightful account of life in Spanish Peru. He also produced a secret report for the Spanish government on the decay and corruption that he had encountered in the colonial administration and church in South America. Juan was obviously a keen-sighted and intelligent observer unafraid of speaking truth to power, all excellent attributes for a spy.

The Spanish officer arrived in London in March 1749 with a cover-story of being a mathematician and astronomer with a thirst for (legitimate) knowledge. On arrival he found that his reputation as a writer and scientist had proceeded him. He was welcomed into the scientific community, gave and attended lectures, and was elected as a Fellow of the Royal Society for his work in Peru. When he expressed an interest in naval architecture, his new friends were happy to endorse him. He soon became a familiar figure in the shipyards of the Thames Estuary, as well as visiting Portsmouth and Plymouth.

Juan’s activity was extraordinary in the year he spent in Britain, all carried out under the benevolent gaze of his hosts. He sent a report to Spain every two weeks, meticulously written in code, detailing ship movements, British construction methods and recommendations about new technology. Some of the industrial practices he came across were little known in Spain, such as the division of labour to streamline production and the early use of steam powered machinery in the Royal dockyards. He also sent back a regular flow of stolen ship’s plans and books on shipbuilding theory.

Perhaps most remarkable of all, he managed to entice over eighty highly skilled shipbuilders to come and work in Spanish yards. These included master shipwrights, sculptors, riggers, carpenters, loftsmen, coppersmiths, sawyers and blacksmiths. Many were Catholics, for whom career progression in Protestant Britain was proscribed by law. Others were drawn by the wages on offer. Edward Bryant, a master shipwright was given a salary of £300 when he started work in Cartagena, three times his annual wage in Britain. Most took their families with them, although this could prove problematic. One furious wife threatened to expose what was going on to the authorities when her husband revealed that the family were not emigrating to Canada, as he had first told her.

The most notable of Juan’s recruits was the Irish shipwright Mathew Mullens, who moved first to Cadiz, and then to Havana in Cuba, where he rose to be in charge of warship design. With access to an abundant supply of tropical hard woods, Havana became one of Spain’s most important shipyards with over a hundred major ships built there. Mullens undoubted masterpiece was the huge first rate Santissima Trinidad which for many years was the largest warship in the world, and served as the Spanish flagship at Trafalgar.

When Juan’s mission was over he returned to Spain. Here he was rewarded by a grateful government with promotion to be in charge of rebuilding the Spanish fleet. Although he had never supervised the construction of a ship, Juan proved to be a very able administrator with the drive to implement the best shipbuilding practices he had witnessed in Britain. The new building methods that were employed were inevitably called ‘Construccion a la Inglesa’ (English construction) but this is to oversimplify matters. What Juan actually achieved was a blend of both the best of British and Spanish techniques. The result was a golden age in Spanish ship building with over fifty of the finest warships of the age of sail being laid down between 1752 and 1760. The superiority of Spanish ship design and construction in this period was freely acknowledged by their opponents, including Nelson. When captured, Spanish prizes always proved to be very popular additions to their captor’s fleet.


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