He was in charge of the Union fleet blockading the port of Galveston, Texas, toward the end of the year, and fought in the First Battle of Galveston. On January 1, 1863, during the Second Battle of Galveston, Renshaw refused to surrender his flagship. He set fire to her to keep her out of Confederate hands, but died in the ensuing explosion. His failure to intercept the cotton ships cost the Union the battle.