USS Tyler was originally a merchant ship named A. O. Tyler, a commercial side-wheel steamboat with twin stacks and covered paddles positioned aft. Constructed in Cincinnati, Ohio in 1857, it was acquired by the United States Navy, 5 June 1861 for service in the American Civil War and converted into the gunboat USS Tyler on 5 June 1861. She was commissioned in September 1861. She was protected with thick wooden bulwarks. Before military acquisition Just four days after Mississippi's secession, on the evening of 13 January 1861, the steamboat was fired upon by cannon used by militia defending Vicksburg. On the Cumberland and Tennessee Rivers Tyler served in the Western Flotilla from June 1861 to 1 October 1862, fighting for the Mississippi River. Soon after being commissioned, Tyler participated in the attack on the Confederate forces in Hickman and Columbus in Kentucky, doing battle with the CSS Jackson. In November 1861, Tyler escorted troops transports for an assault on Belmont, Missouri. Along with , Tyler bombarded Columbus until forced by a Confederate counterattack to cover the withdrawal of the Union troops. In February 1862, Tyler assisted in General Ulysses S. Grant's advance up the Cumberland and Tennessee Rivers, helping in the capture of Fort Henry and Fort Donelson, securing western Kentucky for Federal forces. Between assaults on the two forts, Tyler joined and Lexington moving along the Tennessee River, destroying an important railroad bridge and capturing three Confederate gunboats, most notably the CSS Eastport which was converted into an ironclad for Union service. After participating in the two-day action which culminated in the surrender of Fort Donelson, Tyler resumed operations on the Tennessee River in support of Grant's advance southward along the river's banks through western Tennessee. In the Battle of Shiloh, when Confederate forces under General Albert Sydney Johnston surprised Grant's troops in southwestern Tennessee near Pittsburg Landing and began pushing them back into the river, Tyler and Lexington brought their guns to bear when the Confederates attempted to protect their right flank by anchoring it on the river bank. The two ships delivered a devastating enfilading fire that forced the Southern right flank to fall back. Grant's troops took advantage of the withdrawal to mount a general advance supported by naval ordnance. Thus, victory ensued where debacle seemed imminent. Grant said of this battle, "in this repulse much is due to the presence of the gunboats." The Mississippi