The Impact of Ironclads in the Execution of the Anaconda Plan

Ironclads contributed significantly to the success of General Winfield Scott’s “Anaconda Plan,” which was critical to the Union victory in the Civil War. The plan was two-fold: the Union blockaded Confederate ports and gained control of the rivers, notably the Mississippi River, which were crucial for travel in the agrarian South.

Lincoln and his cabinet did not immediately decide that an actual blockade was the most desirable action. The Lincoln administration never officially acknowledged that the South had indeed left the United States. Any blockade would therefore be a blockade against its own ports. Doing so meant Lincoln was giving tacit belligerency status. As an alternative, he could issue an executive order closing the Southern ports to foreign trade. This, however, was a mere legal formality, relating only to U.S. Customs law, and obviously unenforceable in the seceded states.1 Moreover, European powers might interpret it as a paper blockade. The 1856 Treaty of Paris, concluding the Crimean War, declared such blockades illegal. The U.S. did not sign it, but did officially support it. The Confederacy was desperate for aide from Europe and the Lincoln did not want to do anything to bolster the Confederates’ goals. Britain, acting through its minister to the U.S., Lord Lyons, quietly acknowledged that having used similar blockades before, it could not justifiably object. Comforted by the support of Britain, Lincoln eventually decided that the Union must mount an effective blockade. The Union Navy, however, lacked the ships and manpower needed to seal off the 3,600 miles of Southern coast.

The Union began the war with 90 vessels. This woefully inadequate Navy was functionally smaller still. Twenty-one vessels were unfit for sea, 25 needed repairs and 28 were in foreign stations. Only 15 were available immediately for use.2 The Navy began an ambitious program of rapid growth. They purchased and converted as many ships as possible. By the end of the war, they had added over 600 ships to the Union fleet. Instead of blockading the entire Southern coast, an impossible task, the Union Navy focused on only the ten deep-water seaports with rail connections. By 1865, the Union had built, captured, or purchased 670 ships. Of these, 74 were ironclads.

If the Union Navy started the war off inadequate, the Confederate Navy’s situation was nothing short of tragic. Originally, there was no actual Navy department, only the possessions of the individual states. Though quickly remedied, the complete absence of a national military bureaucracy was difficult to quickly overcome. The British East India Company offered the newly formed Confederacy, in the interval between secession and war, ten quality merchant ships, easily convertible into warships. The total cost to buy, retrofit and deliver was only $10 million.3 It was not a small amount of money, but a ready-made fleet has certain advantages. Nevertheless, the Confederates rejected this offer. They thus began the war with only ten vessels, including the Fulton, which a wreck had seriously damaged and needed repairs before the Confederates could use it.4 Moreover, the South lacked a merchant marine from which to purchase ships suitable for conversion, and from which to recruit talented sailors. By the end of the war, the South had built, captured, or purchased only 130 ships—one fifth of the Union—and only forty of which were ironclads.

On April 19, 1861, the blockade began. As the years passed, the Union Navy grew more powerful and blockade running became increasingly dangerous. By 1864, the Union had already shut down numerous Southern ports. The port city of Mobile was crucial to the Confederacy. It was an important center for iron manufacturing and one of few remaining deep-water ports in the newly formed confederation. General William Sherman, moving closer to Atlanta, desired to keep Confederate reinforcements away. To that end, he urged General E.R.S. Canby to attack Mobile, to keep them occupied. On June 17, 1864, Canby and Admiral Farragut met to discuss the plans. A joint assault would destroy Forts Morgan and Gaines, which protected Mobile Bay. With those out of the way, the army would move to attack Mobile while the navy attacked Fort Powell. Farragut considered it essential that they have ironclads, and worried that they would not be able to procure them.5 Of the 14 ships he originally had, only one was an ironclad. He asked for more from the Secretary of the Navy, who willingly obliged. Though delayed by the need to reinforce General Ulysses Grant, whose Army of the Potomac was dealing the final blows to Robert E. Lee’s battered Army of Northern Virginia, three more ships arrived. With 18 vessels total, including four ironclads, Farragut prepared for the assault. On August 4, Union troops landed on Dauphin Island, on which Fort Gaines was located. On the fifth, the fleet sailed between Forts Gaines and Morgan, staying very close to the latter. The ironclads sailed closest to the fort, protecting the unarmored ships. Once inside the bay, two ironclads were to attack the Confederate ironclad ram, Tennessee, while the other two attacked Fort Morgan. The reality inside the bay, however, was chaos. The wooden Brooklyn entered the bay too fast and the ironclad Tecumseh had to rush ahead, along the edge of a minefield, to prevent the Tennessee from ramming the Brooklyn. Unfortunately, in its haste, the Tecumseh hit a mine on the way. It sunk in four minutes, killing 93 men. Eventually, all of the Union ships made it inside the bay and safely out of range of fire from the forts. The ships skirmished and then retreated to different parts of the bay that evening to regroup and assess damage. Confederate flag officer Franklin Buchanan, planning on a surprise hit-and-run attack, set sail in the Tennessee, by itself, toward the Union fleet. Two Union ships rammed it on the way, five minutes apart, but inflicted little damage. The Tennessee continued forward, receiving numerous shots but no major damage. Its armor was substantially stronger than average. Farragut’s fleet eventually destroyed the Tennessee’s steering and, with ammunition running low and injured by a ricocheting bolt, Buchanan had a subordinate surrender. Despite the gallant effort of Buchanan, the Confederacy was simply out-gunned. The industrial superiority of the North was unquestioned. The South couldn’t build a comparable navy and it couldn’t afford to buy one. The Tennessee was demonstrably stronger-hulled than any one of the Union ironclads, but the Union had three in the mêlée, plus numerous other heavily armed, though not armored, vessels. With no hope, Forts Gaines and Powel surrendered on August 8. Fort Morgan surrendered on August 23, having required two weeks’ bombardment to convince the commander. Farragut left the capture of the city proper to an offensive the next spring. In March 1865, General Canby and Admiral Henry Thatcher combined their forces for the siege of Mobile. The plan, deftly executed, called for the primary land attack to travel up the coast while other forces created a diversion on the opposite side of the bay. The Navy moved people and supplies and provided support for arriving troops. Ceaseless bombardment by ironclad gunboats against the forts guarding the city allowed land forces to move forward. Eventually the siege was successful and the city surrendered.

The open waters of the coast saw some of the more famous actions by the ironclads, but the drama extended to the river battles as well. The Union needed gunboats to overcome the fortifications at Confederate strongholds. The War Department organized, with Navy Department help, a Western Flotilla. It was composed of converted riverboats and seven newly commissioned center-wheel paddleboats. These armored boats, and others later built for the flotilla were important to Grant’s campaigns, beginning February 1862, that eventually led to the control of the Mississippi River. The initial seven ironclads, and two former commercial vessels, since converted, were assigned to seize control of the navigable rivers in the western Confederacy. The industrial weakness of the South required it to rely heavily on fixed embankments along rivers, and very few ironclads to protect the critical interior waterways.

The Union’s first use of ironclads in the river battles was the attack on Fort Henry. The rains of a heavy storm kept Grant’s troops from participating in the action. Union officials felt very confident that the gunboats alone were sufficient for the job. On February 6, 1862, Navy Captain Andrew Foote sent four ironclads to attack the fort. This first attempt proved completely successful. The Union Navy gained greater confidence in their new vessels and the Confederates were terrified. The ironclads, however, had a lot on their side in that particular offensive. Fort Henry had been constructed at a terrible location, and virtually level with the river. As such, its artillery had to fire horizontally, the angle at which the sloped sides of the ironclads were most effective in deflecting projectiles. Moreover, knowing the weakness of the fort, the commander had sent all but a single artillery company to the nearby Fort Donelson.6 Furthermore, the ironclads attacked the fort head-on, their strongest part. For these reasons, the confidence gained in this venture was less than wholly justified.

The Union forces next moved to attack Fort Donelson. The attack, which began on February 14, was a total failure for the Navy. Donelson was strategically far superior to Henry. Its guns were mounted at three different heights, 20, 50 and 150 feet above the water.7 From this position, its guns were able to rain down shells upon the boats below. The strong defense forced all four ironclads to withdraw from battle, seriously damaged and with heavy casualties. By contrast, no Confederate soldier was even wounded. Grant’s army alone captured the fort. This fiasco taught two lessons that would be important in the future: First, the Navy simply was not yet ready for major, inland offenses. It lacked the experience to know which techniques to use, and had not yet determined the most productive use of new iron cladding. Second, it showed the limitations of naval action alone.

Captain Foote took note of these lessons as he led his forces down the Mississippi to attack the next target, Island No. 10. Foote spent weeks anchored upstream of the fortification firing occasional long-ranged and hopelessly inaccurate shots toward it. Downriver, General John Pope was attempting the cross the river in order to cut communications from the island. A Confederate battery prevented his passage, however, and he requested Foote send ironclads down to attack it. Foote was reluctant but eventually capitulated to the orders of his superiors. On April 4, he sent the Carondelet downstream in a then-daring pass. He first ordered the vessel’s deck loaded with iron cables, bales of cotton, lumber and other supplies as additional protection. A storm interrupted the darkness with widely spaced flashes of lightning. The Confederates on Island No. 10 saw the boat and were able to fire many of their cannons. Of the cannons fired, all but two overshot their target. The two that did not overshoot hit only a barge tied to the side of the boat to protect the magazine. The Carondelet suffered no damage. This run led to many others, and indeed the practice became common. The slow, cumbersome loading methods of the era prevented most of the cannons from being able to fire more than once during the run. Moreover, the unsophisticated sights used then made it difficult to aim reliably at a fixed target, even with optimal positions; to do so at a moving target with only intermittent light was impossible. On April 6, the Pittsburg repeated the maneuver of rushing past the fort. The two ironclads completed their requested duty and then returned to just downstream of Island No. 10. Holding a position is far easier to do when the vessel is facing upstream than downstream. Fighting from the opposite site, these two boats were far more effective. The significance of Island No. 10, however, lies in the cooperation between the Navy and Army. Foote’s gunboats provided cover while Pope’s troops landed in a transport, in preparation for the final assault on the island. The commander of Island No. 10, though initially planning to fight to prevent Union troops from landing on his shores, balked when he saw the coverage provided by the ironclads. He sent his forces south, but the ironclads delayed the Confederate troops. Meanwhile, the Union Army raced south on an alternate course. When the Confederates eventually made it south, the Union troops were waiting there and captured them. The Union victory at Island No. 10 confirmed the earlier lesson: the best way to win against Confederate river fortifications was through cooperation between the two branches of the military.8

The following year, the primary concern for the Navy in the Western Theater was the complete control of the Mississippi River. Two major strongholds stood in the way, New Orleans and Vicksburg. The Western Flotilla transferred from the War Department to the Navy Department and became the Mississippi Squadron, a name that reflected the renewed focus. A Confederate gunboat based at Fort Hindman, captured a ship with supplies for Sherman’s troops. General Sherman and Admiral David Porter decided to tackle the fort while waiting to regroup with Grant. On January 9, 1863, the troops landed south of the fort. Union gunboats attacked the fort for an extended period while the soldiers moved into position. The next day, with the soldiers ready for battle, the gunboats again opened fire. After fewer than three hours, the Confederate commander surrendered. The ironclads had dismounted or destroyed every Confederate gun they had fired at. Only one Union boat suffered any damages. The armor sufficiently protected the others.9 After meeting up with Grant, Porter’s ironclad gunboats “ran the gauntlet” at Vicksburg. The boats, repeating the same action as the Carondelet, raced past the city and unloaded downriver, where Grant’s troops were able to launch a successful siege. Without the iron plating, such maneuvers would be too risky to undertake.

Without the successful execution of the Anaconda Plan, a Union victory would not have been possible. While overly optimistic people spoke of a war that lasted months, Winfield Scott knew it would take years. Only a war of attrition could lead to a decisive victory. The blockade, made possible in large part due to the use of ironclads, sharply reduced Southern trade. The river battles of the ironclads divided the Confederacy, interrupted its commerce, and allowed the Union to make use of the South’s interior lines. The use of ironclad vessels significantly contributed to the Union victory.

  1. Nash, Howard P., A Naval History of the Civil War (A.S. Barnes, 1972), 13.
  2. Nash 15.
  3. Nash, 29.
  4. Scharf, J. Thomas, History of the Confederate States Navy (New York: Rogers & Sherwood, 1887; reprint, Freeport, NY, 1969), 24-5.
  5. Tucker, Spencer C., A Short History of the Civil War at Sea (Wilmington, DE: Scholarly Resources, 2002), 142.
  6. Milligan, John D., “From Theory to Application: The Emergence of the American Ironclad War Vessel,” Military Affairs 48, no. 3 (1984): 129.
  7. Nash, 108.
  8. Milligan, 130-131.
  9. United States Naval War Records Office, Official Records of the Union and Confederate Navies in the War of the Rebellion, (Washington, D.C.: U.S. Government Printing Office, 1894-1917), 106.


Primary Sources

Scharf, J. Thomas. History of the Confederate States Navy. 2 vols. New York: Rogers & Sherwood, 1887; reprint, Freeport, NY: Books for Libraries Press, 1969.

United States Naval War Records Office. Official Records of the Union and Confederate Navies in the War of the Rebellion. 27 vols. Washington, D.C.: U.S. Government Printing Office, 1894-1917.

United States War Department. U.S. War Department. The War of the Rebellion: a Compilation of the Official Records of the Union and Confederate Armies. Washinton, D.C.: Government Printing Office, 1880-1901.

Walke, Henry. Naval scenes and reminiscences of the Civil War in the United States. F.R. Reed, 1877.

Secondary Sources

Baxter, James Phinney. The Introduction of the Ironclad Warship. Archon Books, 1968.

Hamersly, Lewis Randolph. The records of living officers of the U.S. navy and Marine corps. J. B. Lippincott, 1870.

Milligan, John D. “From Theory to Application: The Emergence of the American Ironclad War Vessel” Military Affairs 48, no. 3. (1984), 126-132.

Nash, Howard P. Naval History of the Civil War. A. S. Barnes, 1972.

Tucker, Spencer C. A Short History of the Civil War at Sea. Wilmington, DE: Scholarly Resources, 2002.