By 17 December 1766, they were off Cape Virgins, where Wallis had the opportunity to measure the heights of a number of Patagonians. The results—the tallest was 6 feet 7 inches, and most came in under 6 feet—dispelled Byron's notion of ‘Patagonian giants' to whom ‘The Stoutest of our Grenadiers would appear nothing’.
Their passage through the long and narrow Strait of Magellan, seventeen weeks of struggle against strong and contrary winds was particularly gruelling as far as the under-officered and ill-equipped Swallow was concerned. She was in bad shape and continuously lagged behind as Carteret urged that she should be sent home.
Wallis replied that, since their orders tasked the Swallow with accompanying the Dolphin, she would have to do so for as long as possible. He promised to wait when Swallow fell behind, and offer assistance if necessary, but three weeks later off Cape Pillar at the western exit of the strait the two vessels separated in conditions which discouraged Wallis from waiting in the vicinity.
To Wallis, this was, in effect, a happy accident. To Carteret, who had grievances over supplies being carried aboard the larger vessel, it bordered on desertion. While Carteret suspected he had been abandoned, the explanation lies in the combination of the weather conditions and the different sailing qualities of the two vessels, which then went on to complete their voyages independently.
Carteret crossed the Pacific further south than anyone to that time in an unsuccessful search for Davis Land, discovering Pitcairn Island, and made the first European sighting of the New Hebrides since Mendaña two hundred years earlier, though he did not identify islands. In the process, he sliced a fair chunk off the notional undiscovered continent and subsequently carried out useful surveys around New Britain.