He became a privateer during King George's War, part of the War of the Austrian Succession carried out in the North American colonies of Britain and France. He appears to have been in the navy in April and May 1740, serving as master's mate aboard the 50-gun. ON the ship Young Eagle, he made raids on the French fishing fleets and ports on the north shore of Newfoundland. He went on to command his own privateer ship, the 20-gun snow, serving as second in command of the New Englandnaval forces at the Siege of Louisbourg in 1745. On 19 May 1745 he came to the assistance of HMS Mermaid, which was engaged with the 64-gun French. He was the first to render assistance, and the French ship was duly captured. Rous was rewarded for his efforts by Rear-Admiral Sir Peter Warren, who ordered Vigilante be purchased for the navy, and appointed Rous third lieutenant of her on 22 June 1745. Rous remained as captain of the Shirley and was sent to London in July, carrying Warren's dispatches. Warren purchased the Shirley on her return, and on 24 September 1745 Rous was appointed a captain and given command of her. He was present at the Battle at Port-la-Joye. In September 1746 with Annapolis Royal under threat of attack by the remnants of Duc d'Anville's fleet, Captain Rous, commanding the Shirley, was ordered to assist in the defence of the fort. There he along with Captain Richard Spry "agreed to haul their ships under the Fort upon the arrival of the fleet and land their men and guns for the defence of it." In 1747, after the Battle of Grand Pré, Rous sailed for the Minas Basin with a detachment under the command of Captain John Winslow, to re-establish British control over the area. The Shirley was paid off in June 1747, and on 7 May 1749 he took over the 14-gun HMS Albany.
Father Le Loutre's War
Rous was also the senior naval officer on the Nova Scotia station during Father Le Loutre's War. The main officer under his command was Silvanus Cobb. He made a significant contribution to the preservation of Halifax and the defeat of the French, Acadian and Mi'kmaq resistance. He commanded the Albany. As the admiralty did not provide effective naval forces for the defence of Nova Scotia, Rous improvised to establish and protect the new British settlements at Halifax, Lunenburg, and Lawrencetown. He also worked to protect the long established British settlements at Canso and Annapolis Royal, as well as the new British forts in the Acadian communities of Grand Pre, Pisiquid and Chignecto. Under his command were three 14-gun sloops of the Royal Navy, the occasional man-of-war from England, and several New England coasting vessels. In 1753, Rous was a member of the Nova Scotia Council. He took command of the 14-gun in 1753, and in 1755 led the naval force at the Battle of Fort Beauséjour.
