In April 1809, Napier took part in the capture of the Caribbean island of Martinique, and subsequently distinguished himself in the Troude's pursuit of three escaping French ships of the line, handling the small Recruit so well that the British were able to capture the French flagship Hautpoult.
His rank was confirmed on 22 May 1809, but he was put on half-pay, when he came home as temporary captain of the frigate escorting a convoy.