Served as captain of a gun on board the USS Varuna during an attack on Forts Jackson and St. Philip and while under fire and ramming by the rebel ship Morgan, 24 April 1862. During this action at extremely close range while his ship was under furious fire and was twice rammed by the rebel ship Morgan, Bourne remained steadfast at his gun and was instrumental in inflicting damage on the enemy until the Varuna, badly damaged and forced to beach, was finally sunk.