On board the flagship U.S.S. Hartford, during successful actions against Fort Morgan, rebel gunboats and the ram Tennessee in Mobile Bay, 5 August 1864. When other members of his crewgun were killed or wounded under the enemy's terrific shellfire, Pelham calmly assisted the casualties below and voluntarily returned and took his place at an adjoining gun where another man had been struck down. He continued to fight his gun throughout the remainder of the battle which resulted in the capture of the Tennessee.