On 15 August 1806 Westphal was promoted to lieutenant on the sloop in the West Indies. He was captured when the French privateer "Alerte" took , the merchant ship he was returning to England on, during which action he was again severely wounded while leading her resistance. However he escaped from prison in Guadeloupe and was picked up by an American ship. He returned to the West Indies as a lieutenant aboard , and later , ships under the command of Commodore Sir George Cockburn. He fought on land during the 1809 invasion of Martinique.