The delays gave the Spanish time to learn the expedition's objectives and send a powerful squadron to intercept Anson's flotilla. After narrowly evading the Spaniards off the coast of Patagonia, Anson passed through the Strait of Le Maire on 7 March 1741 and began to beat around Cape Horn in the worst season of the year to tackle the worst waters in the world.
While Anson's ships struggled towards the Juan Fernández Islands, the weather took an even higher toll on the Spanish squadron, which was almost completely shattered and in no condition to worry the British expedition.
Anson's Centurion and the Tryal arrived at the Juan Fernández Islands in mid-June, with the Gloucester and the storeship Anna joining them over the next month. The Wager had been wrecked on the desolate coast of southern Chile, with the Severn and Pearl forced back into the Atlantic by tempestuous seas off Cape Horn.
However, while their passage around the Horn, was an epic of endurance it had taken a toll that effectively ruled most of the tasks Anson had been assigned out of the question. Of the 961 men who had sailed in the three remaining warships, 335 remained. Scurvy, cold, and privation had killed the rest, and Anson lacked the numbers to man the Centurion properly.
Still, Anson was determined to do what he could. He left Juan Fernandez in September, moved northwards to make a series of hit-and-run raids along the Pacific coast of South America, took some prizes, burnt the port town of Paita in northwest Peru and arrived off Acapulco too late to intercept the inward-bound Manila galleon.
On that basis, there seemed to be no alternative to returning home the way Drake had gone. On the long westerly passage across the Pacific, scurvy broke out again. The Gloucester, in a bad way already, had to be burnt with her crew transferred to the Centurion which limped into Tinian in the Marianas on 28 August in a desperate condition.