HMS Endeavour[b] was a British Royal Navy research vessel that Lieutenant James Cook commanded to Tahiti, New Zealand and Australia on his first voyage of discovery from 1768 to 1771.

She was launched in 1764 as the collier Earl of Pembroke, with the Navy purchasing her in 1768 for a scientific mission to the Pacific Ocean and to explore the seas for the surmised Terra Australis Incognita or "unknown southern land".

Commissioned as His Majesty's Bark Endeavour, she departed Plymouth in August 1768, rounded Cape Horn and reached Tahiti in time to observe the 1769 transit of Venus across the Sun.

From Batavia Endeavour continued westward, rounded the Cape of Good Hope on 13 March 1771 and reached the English port of Dover on 12 July, having been at sea for nearly three years.

[10] A flat-bottomed design made her well-suited to sailing in shallow waters and allowed her to be beached for loading and unloading of cargo and for basic repairs without requiring a dry dock.

Her hull, internal floors, and futtocks were built from traditional white oak, her keel and stern post from elm, and her masts from pine and fir.

[13] While her main and foremast standing spars were standard for her shipyard and era,[14] an annotation on one surviving ship plan in the National Maritime Museum in Greenwich[15] has the mizzen as "16 yards 29 inches" (15.4 m).

[13] On 16 February 1768, the Royal Society petitioned King George III to finance a scientific expedition to the Pacific to study and observe the 1769 transit of Venus across the sun.

[18] Royal approval was granted for the expedition, and the Admiralty elected to combine the scientific voyage with a confidential mission to search the south Pacific for signs of the postulated continent Terra Australis Incognita (or "unknown southern land").

[7] Endeavour spent the next six months sailing close to shore,[42] while Cook mapped the coastline and concluded that New Zealand comprised two large islands and was not the hoped-for Terra Australis.

[45] On 29 April, she became the first European vessel to make landfall on the east coast of Australia, when Cook landed one of the ship's boats on the southern shore of what is now known as Botany Bay, New South Wales.

[49] When, by Cook's reckoning, about 40 to 50 long tons (41 to 51 t) of equipment had been thrown overboard, on the next high tide a second unsuccessful attempt was made to pull the ship free.

[52] Despite this, Banks noted in his journal the calm efficiency of the crew in the face of danger, contrary to stories he had heard of seamen panicking or refusing orders in such circumstances.

[54] He was entrusted with supervising the task, sewing bits of oakum and wool into an old sail, which was then drawn under the ship to allow water pressure to force it into the hole in the hull.

[60] Endeavour then resumed her voyage westward along the coast, picking a path through intermittent shoals and reefs with the help of the pinnace, which was rowed ahead to test the water depth.

[77] Approximately one month after his return, Cook was promoted to the rank of commander, and by November 1771 was in receipt of Admiralty Orders for a second expedition, this time aboard HMS Resolution.

[84] The third voyage sailed in January 1774 with her purpose to evacuate the Falklands entirely as Britain was faced with political difficulties from the American Colonies, the French and the Spanish.

Endeavour left England in January 1774, sailing from the Falklands with all the British inhabitants on 23 April, leaving a flag and plaque confirming Britain's sovereignty.

[90] Lord Sandwich 2, master William Author, sailed on 6 May 1776 from Portsmouth in a fleet of 100 vessels, 68 of which were transports, which was under orders to support Howe's campaign to capture New York.

On 15 August 1776 Lord Sandwich 2 was anchored at Sandy Hook; also assembled there was Adventure, which had sailed with Resolution on Cook's second voyage, now a storeship, captained by John Hallum.

The Admiralty valuation for 10 of the sunken vessels recorded that many had been built in Yorkshire, and the details of the Lord Sandwich transport matched those of the former Endeavour including construction in Whitby, a burthen of 368+71⁄94 tons, and re-entry into Navy service on 10 February 1776.

[100] A further letter to the Providence Journal stated that a retired English sailor was conducting guided tours of a hulk on the River Thames as late as 1825, claiming that the ship had once been Cook's Endeavour.

[100] In 1991 the Rhode Island Marine Archaeology Project (RIMAP) began research into the identity of the thirteen transports sunk as part of the Newport blockade of 1778, including Lord Sandwich.

[108] On 3 February 2022, the Australian National Maritime Museum (ANMM) held an event attended by federal cabinet minister Paul Fletcher to announce that the wreck had been confirmed to be that of the Endeavour.

In 1886, the Working Men's Progress Association of Cooktown sought to recover the six cannon thrown overboard when Endeavour grounded on the Great Barrier Reef.

[115][116] In 1937, a small part of Endeavour's keel was given to the Australian Government by philanthropist Charles Wakefield in his capacity as president of the Admiral Arthur Phillip Memorial.

[48] They were finally recovered in 1969 by a research team from the American Academy of Natural Sciences,[118] using a sophisticated magnetometer to locate the cannon, a quantity of iron ballast but not the abandoned bower anchor.

[129] The replica vessel commenced her maiden voyage in October of that year, sailing to Sydney Harbour and then following Cook's path from Botany Bay northward to Cooktown.

Her arrival in Sydney was delayed when she ran aground in Botany Bay, a short distance from the point where Cook first set foot in Australia 235 years earlier.

[134][135] While it reflects the external dimensions of Cook's vessel, this replica was constructed with a steel rather than a timber frame, has one less internal deck than the original, and is not designed to go to sea.