The four batteries closest to the fort were each given specific firing missions. Battery McClellan at a range of 1650 yards with two 84-pounder and two 64-pounder James rifled cannon (old 42- and 32-pounders, rifled), was to breach the "pancoupé" between the south and southeast faces and the adjacent embrasure. (A "pancoupè" is a blunted point of a multi-faced fortification.) Battery Sigel at 1670 yards included the five 30-pounder Parrotts and a 48-pounder James rifled cannon (formerly a 24-pounder smoothbore.) Their mission was to fire on the barbette guns until silenced, then switch to percussion shells onto the southeast walls and adjacent embrasure, at a rate of 10–12 rounds an hour to effect wall penetrations for the planned infantry assaults to come later. Battery Totten at a range of 1650 yards with four 10-inch siege mortars was assigned to explode shells over the northeast and southeast walls, or at any hidden batteries outside the fort. Battery Scott at 1740 yards with its three 10-inch and one 8-inch columbiads was to fire solid shot and breach the same area as Battery McClellan.