On May 16, 1861, Commander John Rodgers was directed to report to the War Department for this service. Under his direction there were purchased in Cincinnati three river-steamers, the Tyler, Lexington, and Conestoga. These were altered into gunboats by raising around them perpendicular oak bulwarks, five inches thick and proof against musketry, which were pierced for ports, but bore no iron plating. The boilers were dropped into the hold, and steam-pipes lowered as much as possible. The Tyler mounted six 64-pounders in broadside, and one 32-pounder stern gun; the Lexington, four 64s and two 32s; the Conestoga, two broadside 32s and one light stern gun. After being altered, these vessels were taken down to Cairo, where they arrived August 12th, having been much delayed by the low state of the river; one of them being dragged by the united power of the three over a bar on which was one foot less water than her draught. On the 7th of August, a contract was made by the War Department with James B. Eads, of St. Louis, by which he undertook to complete seven gunboats, and deliver them at Cairo on the 10th day of October of the same year. These vessels were one hundred and seventy-five feet long and fifty feet beam. The propelling power was one large paddle-wheel, which was placed in an opening prepared for it, midway of the breadth of the vessel and a little forward of the stern, in such wise as to be materially protected by the sides and casemate. This opening, which was eighteen feet wide, extended forward sixty feet from the stern, dividing the after-body into two parts, which were connected abaft the wheel by planking thrown from one side to the other. This after-part was called the fantail. The casemate extended from the curve of the bow to that of the stern, and was carried across the deck both forward and aft, thus forming a square box, whose sides sloped in and up at an angle of forty-five degrees, containing the battery, the machinery, and the paddle-wheel. The casemate was pierced for thirteen guns, three in the forward end ranging directly ahead, four on each broadside, and two stern guns.