"Nancy" was in MacIntosh's wharf at Moy (Windsor) when the War of 1812 broke out between the United States and Great Britain. Moved for protection to Amherstburg, the ship was taken by the commander of the British garrison, Lieutenant-Colonel St George, as a transport vessel. Before the war, Lieutenant Colonel Matthew Elliott of The Indian Department had surveyed "Nancy" as part of an inventory of the means available in case of war. According to Elliott, "Nancy" could mount six carriage guns and six swivel guns. The schooner was apparently armed with some guns. Most of these were dismounted from the schooner and used to arm several small gunboats patrolling the Detroit River. At some later date, "Nancy" received two guns and two carronades.