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Copper on the Nuestra Señora de Atocha

Copper on the Nuestra Señora de Atocha

Corey Malcom
Director of Archaeology
Mel Fisher Maritime Heritage Society
March, 1998

One of the larger corgoes put onboard the Nuestra Señora de Atocha in 1622 for the return voyage to Spain, was a 30,000 pound load of copper ingots. Though these ingots have not particularly captured the modern-day public’s imagination, they have played a significant part in all aspects of the wrecked galleon’s story.

Five hundred and eighty-two copper ingots were loaded onboard at Havana, the Atocha’s final stop in the Indies before sailing to Spain. The copper originated from the mine at Caridad del Cobre in the extreme southeast of Cuba. The mine was owned by the crown, and operated by a factor, Juan de Eguiluz. The miners who worked these deposits were slaves of African origin, and, in relation to this, Eguiluz was a man who also had a hand in the slave trade. After the ore was refined, the copper was cast into crude ingots, transported to Santiago de Cuba and then shipped in fregatas to Havana. Eguiluz turned it over to Crown officials at that port city, and it was then loaded onto the guard galleons of the fleet. Only three ships carried this royal cargo of copper in the 1622 Tierre Firme flota; the Atocha, Santa Margarita and Rosario.


The primary reason for shipping copper to Spain was related to the earlier closing of the Havana cannon foundry. On its own, Cuban copper was found to be too brittle for artillery, and when processed resulted in too much waste. When it was taken to Spain and combined with higher-quality Hungarian copper, a better bronze, and thus better, and more reliable guns could be manufactured. Another possible, though undocumented, purpose for shipping copper may have been that in the second decade of the 17th century that the Crown’s New World treasure revenues began to decline. As the supply of silver began to decrease, an incresing number of coins were minted in Spain of a metal known as vellón; an alloy of silver debased with copper.

A random sample of 50 of the Atocha ingots have an average weight of 54.2 lbs, close to the average 51.5 lbs derived for the 582 put onboard when they are divided into their declared weight. Extremes of 22lbs and 111lbs were found on the wreck. Though these ingots are crudely cast, seemingly from simple depressions in the ground, three basic forms have been discerned; rectangular, oval, and an elongated, "boat" shape. All the ingots have highly irregular, bumpy surfaces. None bear markings of any sort The contemporary records of the Atocha’s lading refer to these ingots simply as planchas, with no differentiation for form or size.

During the excavation of the lower hull area of the Atocha, it became apparent how the ingots were loaded on the galleon. Weighing as much as they did, it was logical they would be found in the lower hold. There they could be utilized as ballast, much as the silver bars and coins were. The copper was found in a distinct cluster to the North of the silver. Because the wreck of the Atocha generally faced South, this means the copper was stored nearer to the stern, probably immediately after the mainmast, while the silver was forward of it. The two cargoes complemented each other, providing a balanced load for steady sailing.

ELEMENTAL COMPOSITION ANALYSES OF 
ATOCHA  COPPER INGOTS

*parts per million

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