HMS Dolphin was a 24-gun sixth-rate frigate of the Royal Navy. Launched in 1751, she was used as a survey ship from 1764 and made two circumnavigations of the world under the successive commands of John Byron and Samuel Wallis. She was the first ship to circumnavigate the world twice. She remained in service until she was paid off in September 1776, and she was broken up in early 1777. Construction Built to the 1745 Establishment, Dolphin was originally ordered from the private yard of Earlsman Sparrow in Rotherhithe (under contract dated 7 October 1747). Following Sparrow's bankruptcy in 1748, the order was moved to Woolwich Dockyard. In order to reduce the likely incidence of shipworm, Dolphins hull was copper-sheathed ahead of her first voyage of circumnavigation in 1764. Early service Not long after her commissioning, the hostilities of the Seven Years' War had escalated and spread to Europe, and in May 1756 Britain declared war on France of the Ancien Régime. Dolphin was pressed into service throughout the conflict, and was present at the Battle of Minorca in 1756 when a fleet under Admiral John Byng failed to relieve Port Mahon, Britain's main base in the Western Mediterranean (as a result of which Byng was later court-martialled and shot). First circumnavigation With Britain's successful conclusion of the Seven Years' War in 1763, her attentions turned towards consolidating her gains and continuing to expand her trade and influence at the expense of the other competing European powers. The Pacific Ocean was beginning to be opened up by exploratory European vessels, and interest had developed in this route as an alternate to reach the East Indies. This interest was compounded by theories put forward which suggested that a large, hitherto-unknown continental landmass (Terra Australis Incognita) must exist at southern latitudes to "counterbalance" the northern hemisphere's landmasses. No longer in a state of war, the Admiralty had more funds, ships and men at her disposal to devote to exploratory ventures. Accordingly, an expedition was soon formed with instructions to investigate and establish a South Atlantic base from which Britain could keep an eye on voyages bound for the Pacific. Another purpose was to generally explore for unknown lands which could then be claimed and exploited by the Crown, and to reach the Far East if necessary. Dolphin was selected as lead vessel for this voyage, and she was to be accompanied by