They also took part in the assault of Fort Beaujesour in 1755. In 1757, at the end of July, the company scouted French-occupied Louisbourg in anticipation of Lord Loudoun's (aborted) attack on the fortress. Gorham's men dressed as Acadian fishermen and sailed a captured fishing vessel rechristened "His Majesty's Schooner "Monckton"" directly into the harbor at night. Eventually a French warship fired on them, but the intelligence they gathered, about the arrival of a French fleet and reinforcements, was the deciding factor in Loudoun abandoning the assault. They played an important role in the initial amphibious assault at the outset of the second siege of Louisbourg in 1758, and were vital in the "petite guerre" and scorched-earth operations that took place around the periphery of the siege of Quebec in 1759. In 1761, the unit was officially placed on the British army establishment. The next year they took part in the expedition to Cuba where almost half of the corps died from tropical disease. The unit was disbanded shortly after the capitulation of Havana, and the remaining rangers were drafted into depleted British regiments.