Naval battle of the American Civil War
The Battle of Mobile Bay of August 5, 1864, was a naval and land engagement of the American Civil War in which a Union fleet commanded by Rear Admiral David G. Farragut, assisted by a contingent of soldiers, attacked a smaller Confederate fleet led by Admiral Franklin Buchanan and three forts that guarded the entrance to Mobile Bay: Morgan, Gaines and Powell. Farragut's perhaps apocryphal order of "Damn the torpedoes! Four bells. Captain Drayton, go ahead! Jouett, full speed!" became famous in paraphrase, as "Damn the torpedoes, full speed ahead!"
The battle was marked by Farragut's seemingly-rash but successful run through a minefield that had just claimed one of his ironclad monitors, enabling his fleet to get beyond the range of the shore-based guns. This was followed by a reduction of the Confederate fleet to a single vessel, ironclad . "Tennessee" proceeded to engage the entire Northern fleet. "Tennessee"'s armor enabled her to inflict more injury than she received, but she could not overcome the imbalance in numbers. She was eventually reduced to a motionless hulk and surrendered, ending the battle. With no navy to support them, the three forts also surrendered within days. Complete control of lower Mobile Bay thus passed to the Union forces.
Mobile had been the last important port on the Gulf of Mexico east of the Mississippi River remaining in Confederate possession, so its closure was the final step in completing the blockade in that region. This Union victory, together with the capture of Atlanta, was extensively covered by Union newspapers and was a significant boost for Abraham Lincoln's bid for re-election three months after the battle. This battle concluded as being the last naval engagement in the state of Alabama in the war. It would also be Admiral Farragut's last engagement.
Mobile and Mobile Bay.
 The city of Mobile is situated near the head of Mobile Bay, where a natural harbor is formed by the meeting of the Mobile and Tensaw rivers. The bay is about long; the lower bay is about at its greatest width. It is deep enough to accommodate ocean-going vessels in the lower half without dredging; above the mouth of Dog River the water becomes shoal, preventing deep-draft vessels from approaching the city.
The mouth of the bay is marked on the east by a long narrow peninsula of sand, Mobile Point, that separates Bon Secour Bay, where the Bon Secour River enters the larger bay, from the gulf. The point ends at the main channel into Mobile Bay, and here the United States government erected a pre-war fort to shield Mobile from enemy fleets.
Across the entrance, the line of the peninsula is continued in a series of barrier islands, beginning with Dauphin Island. Northwest of Dauphin Island is Little Dauphin Island, then a series of minor islands that are interrupted by a secondary entrance to the bay, Grant's Pass. A few other small islands and shoals lie to the south of Dauphin Island, defining the main channel for as much as south of the entrance.
Rather early in the war, the Confederate government decided not to defend its entire coastline, but rather to concentrate its efforts on a few of its most important ports and harbors. Following the loss of New Orleans in April 1862, Mobile became the only major port in the eastern Gulf of Mexico that needed to be defended.
The city subsequently became the center for blockade running on the gulf. Most of the trade between the Confederacy, Havana, and other Caribbean ports passed through Mobile. A few attempts were mounted to break the blockade, but they were not large enough to have lasting impact. Among the most embarrassing episodes of the war for the U.S. Navy was the passage of the raider through the blockade into Mobile Bay on September 4, 1862; this was followed by her later escape through the same blockade on January 15, 1863.
Although the orders given to Flag Officer David G. Farragut when he was assigned to command of the West Gulf Blockading Squadron had included instructions to capture Mobile as well as New Orleans, the early diversion of the squadron into the campaign for the lower Mississippi meant that the city and its harbor would not receive full attention until after the fall of Vicksburg in July 1863.
Given respite by the Union strategy, the Confederate Army improved the defenses of Mobile Bay by strengthening Fort Morgan and Fort Gaines at the entrance to the bay. In addition, they set up Fort Powell, a smaller work that guarded the Grant's Pass channel. Grant's Pass was also obstructed by a set of piles and other impediments, which had the effect of diverting the tidal flow to Heron Pass. 
Confederate defenses.
Land.
Mobile and Mobile Bay were within the Department of Alabama, Mississippi and East Louisiana, led by Major General Dabney H. Maury. Although Mobile was the site of the department headquarters, Maury did not exercise immediate command of the forts at the entrance to the bay, and he was not present during the battle and ensuing siege. Local command was entrusted to Brigadier General Richard L. Page.
The primary contribution of the Confederate Army to the defense of Mobile Bay was the three forts. Fort Morgan was a masonry structure dating from 1834. The fort mounted 46 guns, of which 11 were rifled. Its garrison numbered about 600.
Across the main channel from Fort Morgan on Dauphin Island was Fort Gaines, containing 26 guns, and with a garrison of about 600. When Page was not present, command of the fort fell to Colonel Charles D. Anderson.
At the western end of the bay was Fort Powell, smallest of the three, with 18 guns and about 140 men. It was commanded in Page's absence by Lieutenant Colonel James M. Williams. All three forts were flawed in that their guns were unprotected against fire from the rear; in addition, forts Powell and Gaines lacked adequate traverses.
The raw numbers of troops available do not indicate how effectively they would fight. The war was already winding down, and assertions were made that the morale of the soldiers was bad. The judgment is hard to quantify, but it would explain at least in part the poor performance of the defenders.
The Confederate Torpedo Bureau, directed by Major General Gabriel J. Rains, contributed a passive weapon to the defense. Men of the bureau had planted 67 "torpedoes" (naval mines) across the entrance, leaving a gap on the eastern side of the channel so blockade runners and other friendly vessels could enter or leave the harbor. The minefield was well marked by buoys, which Farragut knew well. Its purpose was not necessarily to sink enemy vessels trying to enter, but rather to force them to steer close to Fort Morgan and its guns.
The Confederate military also began construction in 1862 of two forts in Clarke County that were planned to prevent Union advancement into the interior of Alabama in the event that Mobile was captured. These forts, known as Fort Stonewall and Fort Sidney Johnston, also provided protection to the salt works in Clarke County, the Selma Naval Ordnance Works, and Montgomery.
Sea.
The Confederate Navy likewise used the time they were given to improve the defense. Three small sidewheel gunboats of traditional type were stationed in the bay: , carrying four guns; , with six guns; and , also with six guns. In addition to these was the ironclad ram , which, though carrying only six guns, was a far more impressive fighting machine by virtue of her armor.
"Tennessee" had been built on the Alabama River near the town of Selma. Her guns were prepared under the direction of Commander Catesby ap Roger Jones, who had commanded (ex-USS "Merrimack") in her famous duel with on March 9, 1862, the second day of the Battle of Hampton Roads. Jones succeeded to command of "Virginia" after her original commander, Franklin Buchanan, was wounded the previous day. Buchanan had been promoted to the rank of admiral for his exploits that day, the first admiral in the Confederacy. Admiral Buchanan was now in command of the small Confederate flotilla at Mobile.
Launched before her machinery and guns were in place, "Tennessee" was towed down to Mobile Bay for completion. Once that was done she had to cross the Dog River Bar to get into the lower bay. "Tennessee" drew , but the bar had only of water at high tide. To get her across, workers had to build a set of caissons, called "camels" by shipbuilders. These were fitted to her sides and pumped out, and barely lifted the ship enough to clear the bar. On May 18, 1864, she finally entered the lower bay.
"Tennessee" was the only armored vessel that the Confederate Navy put into lower Mobile Bay, but there were plans for others. Buchanan hoped that he would have as many as eight, including a pair of floating batteries, with which he could challenge the Union blockade, attack Pensacola and perhaps even recapture New Orleans. The manufacturing and transportation facilities of the South were not capable of this ambitious program, however, some of the projected fleet were completed in time to defend Mobile after the lower bay had been lost, but they were not there when most needed. Nevertheless, they imparted some urgency to Farragut's plans to maintain the blockade.
The United States.
Union Navy.
The man who led the Union fleet at Mobile Bay was Rear Admiral David G. Farragut, no longer Flag Officer Farragut. The U.S. Navy had undergone an organizational change in the second year of the war, one feature of which was the creation of the rank of rear admiral. The new rank implied that the ships of the navy would be employed as members of a fleet, not simply as collections of vessels with a common purpose.
The ships that made up his attacking fleet were of several distinct types, including some that had not even existed when the war began. Of the 18 vessels selected, eight were conventional wooden-hulled ships carrying large numbers of guns that fired broadside. Four of these had been with the West Gulf Blockading Squadron from the start (flagship , , , and ) and had fought in its battles on the Mississippi. Two smaller gunboats had likewise been with Farragut since the capture of New Orleans: and .
 was now very much like the others, but she had begun life as an experimental ironclad. Her armor had been found to be more hindrance than help, so it was removed. Three were double-enders (, , and ), a type of warship that had been developed during the war to navigate the tortuous channels of the interior rivers. Finally, four were representatives of the New Navy: ironclad monitors. Of these, and were improved versions of the original , armed with two large guns in a single turret. The and were twin-turreted river monitors of light draft; each mounted four guns that were smaller than those carried by the other two.
Union Army.
Army cooperation was needed to take and hold the enemy forts. The commander of the Military Division of West Mississippi was Major General Edward Richard Sprigg Canby, a career soldier with whom Farragut worked in planning the attack on Mobile. He calculated that 5,000 soldiers could be taken from other responsibilities in the division, enough to effect a landing behind Fort Morgan and cut it off from communication with Mobile. Their plans were undercut, however, when General-in-Chief Ulysses S. Grant made an urgent call for troops to be sent to the Virginia theater, then entering its critical phase.
Canby then believed that he could spare no more than 2,000, not enough to invest the largest fort but enough to take Dauphin Island and thereby secure contact between the fleet inside the bay and their support in the gulf. Canby and Farragut recognized that they would not be able to threaten Mobile, but possession of the lower bay would be of great enough use to the blockading fleet that the projected attack should not be canceled.
Communication would be necessary between the fleet and the landing force, so Canby suggested that a contingent of his signal corpsmen be distributed among the major ships of Farragut's attacking force. Farragut accepted the offer. This almost casual mingling of the services was found quite useful during the battle.
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