By the summer of 1864, the blockade of Confederate ports was nearly at its zenith. Mobile, Alabama, was one of only two major operational ports in the Confederacy (the other being Wilmington, North Carolina). Mobile Bay was massive, spanning some 413 square miles. However, while the bay itself was vast, it only had two narrow Gulf-facing entry points or ship channels. The first was a split between Dauphin Island and the Fort Morgan Peninsula running east to west. The second entry point, Grant’s Pass, was a narrow opening on the northside of Dauphin Island, between the island and the mainland at Cedar Point. From the mouth of Mobile Bay to the city of Mobile is roughly 31 miles as the crow flies. The defenses near the mouth of the bay were formidable. A British foray into this area during the War of 1812 illustrated the importance of properly fortifying the bay. Thus, three forts defended the shipping channels, the largest being Fort Morgan, a 46-gun, star-shaped fortification constructed in 1834 protecting the deepest channel from its eastern side. On the west side of the channel, on Dauphin Island, the smaller and newer Fort Gaines boasted 26 guns. Fort Powell guarded Grant’s Pass at the western entrance of Mobile Bay with 16 guns.
To supplement these defenses, the Confederates had blocked part of the main channel with torpedoes (floating wooden barrels of explosives like modern naval mines) and assembled a small flotilla consisting of the ironclad CSS Tennessee and three gunboats inside the bay. They were commanded by the veteran Adm. Franklin Buchanan, former commander of the ironclad CSS Virginia.
Tasked with closing the port was Rear Adm. David G. Farragut. Farragut devised a combined army-navy operation that would entail landing some 1,500 solders commanded by Maj. Gen. Gordon Granger on Dauphin Island to lay siege to Fort Gaines. Granger’s force established a beachhead on August 3 and laid siege to Fort Gaines while Farragut assembled his fleet of four ironclad monitors and more than a dozen wooden ships offshore. Early in the morning of August 5, 1864, the Federal fleet passed into the harbor.
Farragut split his ships into two parallel columns: the ironclads sailing nearest Fort Morgan and the wooden ships on the far side. Farragut ordered the larger wooden ships lashed together to a smaller ship so that the larger vessels could serve as shields, and so the ships would be able to tow each other if one became crippled. Farragut personally observed much of the battle while lashed to the rigging of his flagship, the USS Hartford.
The ships steamed through the narrow width of the channel that had not been mined while passing under the guns of the fort. The ironclad USS Tecumseh struck a torpedo and sank almost instantly, and cautious Union captains began stopping their ships while still within range of Fort Morgan. At this juncture, Farragut allegedly bellowed, “Damn the torpedoes! Full speed ahead!” (although more reliable accounts suggest a slight variation to this quote).
The Hartford made it through the minefield with the rest of the fleet following in its wake. Once into the expansive bay, Farragut engaged with the Confederate ships. The Federals quickly captured or drove away the Rebel gunboats Selma, Gaines, and Morgan, but despite the overwhelming odds, the Tennessee, Buchanan’s flagship, moved forward to meet the northerners. Buchanan was soon surrounded by Federal ships. The Tennessee’s weak engine made her too slow to outmaneuver her adversaries. The ships fought at point-blank range.
Eventually, Buchanan was injured, and his ship was disabled after three hours of fighting. While the city of Mobile would not fall until 1865, Fort Gaines surrendered on August 8 and Fort Morgan fell on August 23. Farragut's victory at Mobile Bay cut off one of the last of the Confederate’s deep-water ports and helped to secure President Abraham Lincoln's reelection in November.