 She remained there until early July, when she made a quick run up the Mississippi River, carrying letters and passengers to the warships participating in the siege of Vicksburg, Mississippi.Returning down river, "De Soto" sailed southeast along the coast of Texas, patrolling off Sabine Pass, the Brazos River and Brazos Santiago at the mouth of the Rio Grande.Three months of hot weather and lack of maintenance facilities took a toll on "De Soto's" boilers and she returned to New Orleans, Louisiana, for temporary repairs in early October.