Gorham's regiment made up the majority of men who attacked the island battery in Louisbourg Harbor during the siege—suffering significant casualties in a series of failed amphibious assaults.
He later commanded another provincial company stationed at the Annapolis Royal garrison at Fort Anne in Nova Scotia in 1746-47, and was later captain of a small armed vessel based there.
Cobb's vessel became part of Captain John Rous's sea militia which helped keep open communications along the coast of Nova Scotia and with New England.
Governor Edward Cornwallis described Cobb as a settler who "knows every Harbour and every Creek in the Bay [of Fundy], a man fit for any bold enterprise."
He returned to Halifax with the news and was ordered by Governor Charles Lawrence to blockade the harbour until Captain William Kensey (MacKenzie?)
Capt Cobb returned to Plymouth after the campaign and moved, with his family, to Liverpool, Nova Scotia where he is said to have built a house.
He was afterwards employed in the Expedition against Havana in 1762, where he died of the epidemic which there prevailed, expressing his regret that he had not met a soldier's death at the cannon's mouth.