Promoted to post captain in 1740, Cotes was appointed to the command of the third-rate HMS Edinburgh in 1745 and saw action at the Second Battle of Cape Finisterre in October 1747.

[1] Cotes was named Commander-in-Chief of the Royal Navy's Jamaica Station in early 1757, shortly after formal declaration of the Seven Years' War against France.

[3] Suspecting he was badly outnumbered, Townshend had adopted a defensive position at Jamaica and written for help from both England and from the small Royal Navy contingent in the Leeward Islands.

[3][4] Cotes took advantage of his unexpected naval superiority by deploying his ships of the line to watch over Cap-Haïtien, while his frigates cruised for stray French commercial craft.

His larger vessels were in need of repair and had been returned to Jamaica; in their place Cotes ordered the readying of a three-vessel squadron comprising the 60-gun ships Augusta and Dreadnought and the 64-gun Edinburgh.

The French vessels were more swiftly repaired, and put to sea before Forrest could return; the merchant convoy reached France in relative safety over the winter.