Chronic ailments forced Schuyler to return to Albany in mid-September 1775, leaving the expedition in the able hands of General Montgomery. Using the intelligence he had obtained during his reconnaissance mission, he devised a plan to besiege Fort St. John and cut off its line of communication to other British outposts farther north such as Fort Chambly.
"To land as near the Fort as we did the first Time we went down, The two Row Gallies carrying a twelve Pounder each and well manned The Sloop & Schooner and ten Batteaus with picked Men to lay in the River, ready to attack the Enemy’s Schooner (which is compleat and carries 16 Guns) in Case she should attempt to destroy our Boats or get to the Southward of them & thereby effectually cut off all Communication between this Place and the Army— After this Naval Arrangement (which will take 350 Men) 500 Men to be sent as a Corps of Observation to intercept any Succours between St Johns and Chamblee . . . two hundred Men at the proposed Landing to cover the Boats . . . the Remainder of the Army to invest the place, make the Approaches & erect the Batteries."
General Schuyler to General Washington, 20 September 1775www.founders.archives.gov