There was certainly no shortage of owners willing to sell their steamboats to the Army for a handsome price. In a stroke of luck for the United States, most of the shipping on the Mississippi and its tributaries was under Northern ownership. And after the introduction of non-intercourse laws, many vessels were left idle in port, barred from trading with the new Confederate enemy.
So with a glut of available shipping and unemployed laborers, Navy Commander John Rodgers enjoyed a wide selection of some of the choicest vessels in the West. From May 1861 onward, Rodgers, as an agent of the Army, purchased a large number of formerly civilian steamboats. Most of these acquisitions would go on to serve as troop and supply transports operated by the Army Quartermaster Department. A smaller number would be converted to fight.
While Rodgers, Eads, and Pook hammered out the designs for a new class of purpose-built ironclads, on 7 June Rodgers bought three commercial steamboats at Cincinnati, Ohio. These vessels were the A.O. Tyler, Lexington, and Conestoga, approved in consultation with constructor Samuel Pook and General McClellan. With major structural improvements, initial price estimates placed each vessel at $34,000.
Refitting these civilian craft for combat service required a prodigious amount of labor and capital, and Rodgers wasn't confident the makeshift fleet could get the job done. In early June, the captain wrote to Secretary Welles of the difficulties he faced:
All the river boats are so different from war vessels in all their appliances that considerable alterations are necessary to fit them for use. They needed a good deal of strengthening, and because the crew would be liable to be picked off while passing along the banks of the river in places where no effectual return could be made to the fire of an individual, I decided upon putting bulwarks of oak plank 5 inches thick, which I found by experiment a sufficient guard against small arms. The boiler and engines cannot be defended against cannon shot. We must take our chances.
The trio of steamboats needed new, strengthened internal supports to manage the extra weight of cannon, equipment, and expanded crew. To clear space for the men at quarters, their engines and boilers were dropped into the unprotected hold. High wooden walls were added to provide security for the crew. Unlike future fighting vessels on the Mississippi, The Tyler, Lexington, and Conestoga would not be encased in iron. The thick, oaken bulwark Rodgers described to Welles would be their only real protection in an engagement. They would be clad in timber. In a final iconic touch, Pook gave each timberclad two extra-tall smokestacks (or "chimneys") which helped visually distinguish this unique class of fighting ship.
Although their armament was minor compared to the deep water ships of the US Navy, the Timberclads still packed a punch. In its 1861 state, the Tyler carried six 8-inch guns and an additional 32-pounder cannon. Her sister ships were roughly as powerful. While the Timberclads were not suitable to go tête-à-tête with a Confederate ironclad, they would provide valuable security for troop and supply movements. And, as at the Battle of Shiloh in April 1862, these hardy boats could bombard enemy troops and help turn the tide of a land engagement.
Low water in the Ohio River prevented the Timberclads from arriving at Cairo until August 12. Within weeks, however, these first Western Gunboat Flotilla vessels would begin interdicting illicit trade with the South, and soon encountered real challenges.
For more information on the Timberclads, see Craig Swain's Civil War Navy Sesquicentennial piece on the Tyler. The authoritative work on this class is Myron J. Smith's The Timberclads in the Civil War: The Lexington, Conestoga, and Tyler on the Western Waters.