The Main Thrust: The West or East Indies?

The declaration of war in October put Britain on a course into the unknown. Never before had Britain plunged into a conflict with a major European power without allies. That the campaign would take place in the late summer and autumn of 1740 against the Spanish colonies in the Caribbean underlay both the expectation of a swift victory and the declaration of war. Over the coming winter and spring the forces had to be assembled and during this time France had to be kept neutral. A great deal was being gambled on an ability to do both.

The Spanish Empire in America was a vast region that stretched from Buenos Aires in the south to St Augustine in Florida to the north. At the heart of the empire were the silver mines in Peru and Mexico and it was the treasure fleets, bringing silver back to Spain that was the main focus of British attention. The Galeones and the Flota provided the crucial link between Spain and her American colonies. The latest Galeones had arrived in Cartagena in 1737 and was awaiting the arrival of silver bullion from Peru to go on to Porto Bello for the fair before returning home. The Flota was preparing in Cadiz for its outward journey. However, silver not only came eastward to Spain, but was also sent west, across the Pacific Ocean from Acapulco to Manila, where it was a valuable element in the Spanish trade to China. The galeon, which took the silver to Manila was a rich if distant ‘Prize of all the Oceans’.

It had long been understood that the vulnerability of the empire lay in these lines of communication from Porto Bello and Vera Cruz to Cadiz and from Manila to Acapulco. The initial plans for deploying ships under Vernon and Haddock were to intercept the treasure ships. However, from the British point of view the capture of any outposts near the key trade routes could present a permanent threat to Spain. As early as 3 June, Sir Charles Wager presented a proposal to take Porto Rico as this island lay at the point where Spanish ships traditionally sailed into the Caribbean.