 Trade on the river was suspended for two years because of a Confederate blockade.The triumph of Eads ironclads, and Farragut's seizure of New Orleans, secured the river for the Union North.The worst of all steamboat accidents occurred at the end of the Civil War in April 1865, when the steamboat "Sultana", carrying an over-capacity load of returning Union soldiers recently freed from Confederate prison camp, blew up, causing more than 1,000 deaths.