Henry Mowat of the Albany was familiar with Massachusetts politics, and he took the rumors quite seriously and convinced General McLean to leave additional ships that had been part of the initial convoy. Some of the convoy ships had already left, but the orders were countermanded before armed sloops North and Nautilus were able to leave. American reaction When news reached the American authorities at Boston, they hurriedly made plans to drive the British from the area. The Penobscot River was the gateway to lands controlled by the Penobscot Indians who generally favored the British, and Congress feared that they would lose any chance of enlisting the Penobscots as allies if a fort were successfully constructed at the mouth of the river. Massachusetts was also motivated by the fear of losing their claim over the territory in any post-war settlement. To spearhead the expedition, Massachusetts petitioned Congress for the use of three Continental Navy warships: the 12-gun sloop Providence, 14-gun brig Diligent, and 32-gun frigate Warren. The rest of more than 40 vessels were made up of ships of the Massachusetts State Navy and private vessels under the command of Commodore Dudley Saltonstall. The Massachusetts authorities mobilized more than 1,000 militia, acquired six small field cannons, and placed Brigadier General Solomon Lovell in command of the land forces. The expedition departed from Boston harbor on July 19 and arrived off Penobscot on the afternoon of July 25. Landing On July 25, nine of the larger vessels in the American flotilla exchanged fire with the Royal Navy ships from 15:30 to 19:00. While this was going on, seven American boats approached the shore for a landing, but turned back when British fire killed a soldier in one of the boats. On July 26, Lovell sent a force of Continental Marines to capture the British battery on Nautilus Island (also known as Banks Island), while the militia were to land at Bagaduce. The marines achieved their objective, but the militia turned back when British cannon overturned the leading boat, killing Major Daniel Littlefield and two of his men. Meanwhile, 750 men landed under Lovell's command and began construction of siege works under constant fire. On July 27, the American artillery bombarded the British fleet for three hours, wounding four men aboard HMS Albany. Assault On July 28, under heavy covering fire from the Tyrannicide, Hunter, and Sky Rocket, Brigadier General Peleg Wadsworth