Bettesworth remained with
Phoebe until January 1804 when was he was promoted to lieutenant on
HMS Centaur. On 4 February 1804 he took part in a cutting out expedition that captured the 16-gun French privateer
Curieux at
Fort Royal harbour,
Martinique. Bettesworth received a slight wound in this engagement. The
Royal Navy took
Curieux into service as the
sloop-of-war HMS
Curieux. After her first commander, Robert Carhew Reynolds, died of the wounds he had received during her capture, Bettesworth then became her commander. While captain of the
Curieux, Bettesworth one day took her jolly boat in shore, together with the purser, who played his violin. A local black came out of the undergrowth on shore and held up a pair of fowl, indicating that he sought to sell them. Bettesworth took the bait and had his men row to the shore. The moment the boat touched the beach, a squadron of cavalry burst from the undergrowth. Their gunfire wounded Bettesworth in the thigh, causing substantial loss of blood, and broke the coxswain's arm. At Bettesworth's urging, the crew of his boat got it off the beach and rowed back to
Curieux. On the way back Bettesworth wanted to open a bottle of champagne, but the purser broke it in his nervousness. On 8 February 1805,
Curieux chased the French 16-gun privateer
Dame Ernouf for twelve hours before being able to bring her to action. After forty minutes of hard fighting the Frenchman, which had a larger crew than
Curieux, maneuvered to attempt a boarding. Bettesworth turned with the result that the French vessel got stuck in a position where
Curieux could rake her deck. Unable to fight back, the
Dame Ernouff struck.
Curieux suffered five killed and four wounded, including Bettesworth, whom a musket ball had hit in the head. The Frenchman had 30 killed and 40 wounded. The French recaptured
Dame Ernouf shortly thereafter, but the British then recaptured her again too. That same year (1805) he brought home from
Antigua despatches from Admiral
Nelson, apprising the government of Admiral
Villeneuve's homeward flight from the
West Indies. On the way Bettesworth spotted the French fleet and alerted the Admiralty. His information led to Rear Admiral
Robert Calder's interception of the Franco-Spanish fleet at the
Battle of Finisterre. For his services, Lord
Barham promoted Bettesworth to
Post-Captain. ==HMS
Crocodile==