"Swift" was Bowyer's only command as a commander because on 28 October 1762 he was promoted to post-captain. He was given command of the frigate HMS "Sheerness" at the same time and served in her in the Mediterranean until 17 December 1763 when he paid her off, the Seven Years' War having ended. Bowyer stayed unemployed until the American Revolutionary War began, when on 31 October 1776 he was given command of the ship of the line HMS "Burford" in which he served off the coast of Ireland. He left "Burford" to recommission the ship of the line HMS "Albion" on 4 May 1778; on 9 June he sailed her to North America before travelling to the West Indies on 13 December as part of the fleet of Vice-Admiral John Byron. As part of the fleet Bowyer fought at the Battle of Grenada on 6 July 1779.