This is the first of three posts on the assault on Mobile Bay.
Mobile Bay, along the Alabama Gulf coast was one of the remaining major ports available to the Confederacy by 1864. The Union blockading squadrons had been able to shut all the other ports except for Mobile Bay and Wilmington, North Carolina.
Mobile Bay is a large inlet some 31 miles deep and at places 24 miles wide, extending north from the Gulf of Mexico. Feeding into the bay were the Mobile and Tenshaw Rivers which were part of a network of inland waterways. Thirty miles north of the city of Mobile, the Alabama and Tombigbee Rivers joined to form the Mobile River. The Mobile & Ohio Railroad ran from the city to Columbus, Kentucky. It was the longest rail line in the Confederacy.
The city of Mobile had been the second-largest cotton exporting port in the South, next to New Orleans. Blockade runners steamed between Mobile and Bermuda, Nassau and Cuba with commodity exports and high value material imports. The state of Alabama was second only to the Tredegar Iron Works in Richmond as the South’s center for manufacturing iron and rolling heavy plate.
Selma was 130 miles north of Mobile along the Alabama River. Henry D. Bassett’s Ship Yard there was in the process of building three ironclads. In all, eight ironclads were being constructed on the Alabama and Tombigbee Rivers. Only one, the CSS Tennessee was to be completed in time to see action. The need to halt further ironclad production by the Confederacy was one of the more important reasons to capture the bay and the city.
Mobile Bay was a difficult target. The bay entrance narrowed to only three miles wide. On the western side of the entrance Fort Gaines guarded it on Dauphin Point. The fort is a masonry fortification that was established in 1821. During the battle the fort was equipped with 26 guns and had a garrison of 600 soldiers. East from the fort, the Confederates had sunk a series of pilings that reduced the width of the opening by over half.
From the pilings east, the Confederates had placed three lines of torpedoes (mines). Those and the shallow water reduced the entrance even further. Each line of torpedoes was staggered behind the other in order to prevent a vessel of any size from slipping through. Brig. Gen. Gabriel Rains, who had pioneered the use of land mines during the 1862 Peninsula Campaign, had been the architect of these defensive measures.
On the eastern edge of this formidable minefield, there was a narrow 200 yard opening for the passage of blockade runners. Fort Morgan, a large star-shaped masonry fort guarded this entrance. The fort had been completed in 1834. At the time of the assault the fort was equipped with 47 guns and garrisoned by about 600 men.
A third smaller fort, Fort Powell, guarded Grant’s Pass a narrow intercoastal waterway north of Dauphin Island. Fort Powell was equipped with 12 guns (another source says that it had 18 guns) and was garrisoned by about 140 men from the 21st Alabama Infantry.
Within the bay itself, the Confederates had the CSS Tennessee and three sidewheel steamer gunboats, the CSS Selma, CSS Morgan and CSS Gaines. The Tennessee’s captain was Commander James D. Johnston. The Tennessee carried six guns as did the Morgan and the Gaines. The Selma carried four guns. The overall naval commander was Admiral Franklin Buchanan, who had been the original commander of the CSS Virginia before being wounded. The Tennessee was Buchanan’s flagship.
The Tennessee was a formidable weapon with six inches of armor on her casemate, five inches on her sides and two inches on her deck. She was equipped with six Brooke rifles. Two were 7 inch and four were 6.4 inch rifles. Due to the extreme weight of armor and armament, the Tennessee was inadequately powered and could only make 5 knots. This lack of power made her difficult to maneuver.
The force that Admiral David Farragut had assembled was formidable, Included in it were four newer ironclads. The USS Manhattan and the USS Tecumseh were large vessels that mounted 2-15 inch Dahlgren guns that were protected by 11 inches of turret armor. The USS Chickasaw and the USS Winnebago were twin-turreted river monitors equipped with 4-11 inch Dahlgren smoothbores.
In addition to the powerful ironclads, Farragut had 14 wooden vessels and an Army contingent of 2,000 men. Included among Farragut’s ship was his flagship, the USS Hartford and the USS Brooklyn. The Hartford was a 24-gun sloop-of-war. The Brooklyn carried 21 guns.
The campaign to take Mobile Bay was to begin on August 2, 1864 and conclude on the 23rd.