The Union column enters Mobile Bay's minefield

The attack began with the tide running in and a Union force that combined twelve wooden warships, two partly armoured gunboats, and four monitors. Farragut planned to use the ironclads to absorb and return fire while the rest of the column forced the entrance. Brooklyn led the wooden ships because four chase guns gave her more forward fire, and she carried a mine-deflecting device that Farragut called a cowcatcher. The formation also reveals the limits imposed by the fort and minefield, which constrained firing angles and divided the Union ships between engaging Fort Morgan and the Confederate squadron.