The Civil War and the Transformation of Naval Warfare


Friends of Padre Steve’s World

For the past month I have been doing a lot of work on my Civil War and Gettysburg text. As I looked at the first chapter which deals with the Civil War being the first truly modern war, I realized that the text was entirely land-centric. Part of this was because no naval forces were involved at Gettysburg, but they did have a significant and even a pivotal role in the defeat of the South. The technical developments at sea during the Civil War still affect us today. Since many of my students are Naval officers and our Staff College focuses on joint operations I thought it wise to include a brief introduction to those transformational developments of the Civil War.


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Another aspect of the American Civil War that made it the first modern war was the naval war. There are several components of which we should take note. The first of which are the major technical advances in naval warship design, particularly in the matter of armor protection and steam propulsion. While both armor protection and steam propulsion were not new. Steam power had been introduced in the United States Navy in 1814 when Robert Fulton’s USS Demologos was launched. That ship was innovative but saw little service. The U.S. Navy commissioned a number of steam frigates, first paddle-wheel steamers and later screw-frigates in the 1830s, 1840s and 1850s. However during the ante-bellum era only seventeen of fifty-seven major ships (ships of the line, frigates and first rate sloops of war) were steam powered. By the end of the war most ships were steam powered or had sails just to supplement their steam plants.

The second major technical innovation was the use of iron in shipbuilding, particularly armor plating for protection. What had changed was that the French and British navies had adopted explosive shell in the 1830s. The first use of them by the Russians against the Turks at the Battle of Sinope in 1853 proved devastating to the Turks and convinced both the British and the French that something had to be done to counter the threat. The result was the ironclad.

During the Crimean War the French built ironclad floating batteries as well as “three small purpose built…gunboats…whose ironclad hulls proved equally impervious to solid shot and explosive shell.” [1] The French commissioned their first ironclad shell firing battleship, the Gloire in 1859. The British Royal Navy commissioned their first ironclad, the HMS Warrior in 1860. Though she did not have the rotating turrets and maintained sails as an auxiliary source of propulsion, Warrior was “rightly regarded as the first battleship of the modern age. Warrior was steam-propelled, shell firing, iron in construction from keel to bulwarks and heavily armored as well.” [2]

But it was in America that the steam powered ironclads changed naval warfare in a dramatic fashion. The Confederacy led the way in the development of ironclads largely out of necessity to break the Union blockade. As necessity is the mother of invention the Confederates were most creative in attempting to answer the Union blockade, which was tightening significantly by 1862 as Union Naval and Army forces conducted amphibious operations along the Confederate Coast seizing six of the nine ports with rail connections to the southern interior, while blockading the remaining ports. The “blockade reduced the South’s seaborne trade to less than a third of normal,” [3] which included imports of vital war materials as well as the export of the South’s only real commodity, cotton.

The blockade had a devastating effect on the southern economy and war effort: “by bringing about serious shortages in strategic items, not only added to the inflationary trends but also frustrated efforts to maintain the transportation network and to increase industrial output.” [4] A southern naval officer “conceded after the war that the blockade “shut the Confederacy out from the world, deprived it of supplies, weakened its military and naval strength.” [5] It also contributed to the decline in the southern standard of living, weakening the political will of the southern people by “accentuating the hardships of war by reducing the southern standard of living and denying consumers enough of many of the imports, such as coffee, which they valued. This was a cost of war which northerners did not have to bear.” [6]

The blockade and Union amphibious operations soon deprived the Confederacy of its major naval facilities and forced the confederate Navy to rely on small shipyards in often isolated locations. The isolation meant that the often paltry amount of supplies such as iron, wood, and weapons, could not get to these facilities, hindering the construction of warships. But the Confederate Navy also suffered from its secondary status to the Army and since “Davis favored the army, the navy received inadequate funding.” [7]


CSS Virginia in drydock

Despite this, southern naval personnel were decidedly inventive in attempting to find creative ways to defend their harbors as well as break the blockade. First was in the development of ironclad ships armed with large rifled cannons which fired the explosive shells which were so devastating against wooden ships. The first operational Confederate Ironclad the CSS Manassas was destroyed at New Orleans by Admiral Farragut’s fleet, but the most famous Confederate Ironclad had a decided effect on the war. This was the CSS Virginia formerly the Federal steam frigate USS Merrimac which had been burned at Norfolk to prevent her from falling into Confederate hands. The ship had burned to the waterline but its hull was intact. Likewise its engines, which even before the sinking were seriously in need of replacement, were intact.

Confederate Secretary of the Navy Stephen Mallory realized that innovation was the key to Confederate hopes at sea and he told the Naval Affairs committee in the new Confederate Congress “I regard the possession of an iron-plated ship as a matter of first necessity.” [8] Mallory sent agents to Europe to contract with French and British yards to build such ships but those efforts fell through when both countries decided to enforce their neutrality laws which forbade them from producing warships for a belligerent nation.

This caused Mallory to embark on converting the Merrimac into a large ironclad ram. In 1861, not long after the seizure of Norfolk and the Gosport Naval Shipyard, Mallory’s Chief of Ordnance and Hydrography, Lieutenant John M. Brooke, “had drawn up a design for transforming Merrimac’s hull into the iron plated CSS Virginia.” [9] The ship was cut down to the waterline and rebuilt with a “170 foot long casemate sloped at an angle of 36 degrees” [10]bolted onto the hull. Construction was agonizingly slow despite the efforts of officers on the scene. The ship’s executive officer, Lieutenant Catesby ap R. Jones “pressed the workmen to labor overtime, seven days a week” [11] but despite their efforts the ship was completed nearly four months after its projected completion date of November 1861. This was largely due to issues that would plague the Confederate shipbuilding industry throughout the war; “shortages of iron, congestion on the railroads hauling materials, and the necessity of retooling the Tredegar Iron works[12] to roll the armor plate slowed her construction.

The ship’s casemate had a four inch layer of armor plate, and the hull below was given a one inch armored belt extending to three feet below the waterline. Armed with six 9 inch Dahlgren smoothbore naval guns on the broadside, two 7 inch rifles forward and two 6.4 inch rifles aft and equipped with a seven foot iron ram on her bow, when complete, the new Virginia was unlike anything seen before. [13]

During construction Union spies leaked the plans to the North which catapulted the Lincoln and his Secretary of the Navy Gideon Welles into action. “When Welles learned of enemy plans for Merrimac, he appointed an Ironclad Board to study the problem. It recommended that the Navy Department let contracts for three experimental ironclads, one of them designed by John Ericsson and known as the Monitor.[14]


Ericsson, a Swede, was the inventor of the screw propeller and designer of the first U.S. Navy Screw Frigate the USS Princeton. The Monitor too was like nothing ever seen on the ocean. Described by some as a “cheese box on a raft” the small ship had all of her machinery located below the waterline on a completely iron hull that only drew 11 feet of water. The hull was protected by armor plate, but the most notable and innovative feature was a heavily armored revolving turret with eight inches of armor, mounted two massive 11 inch Dahlgren smoothbore guns which “could fire a 170-pound shot or 136-pound shell in any direction except straight ahead, where the pilot house sheathed in nine inches of armor was located.” [15] Future ships remedied this defect. Ericcson’s ship was mocked around the navy and by naval designers, but he and it would prove them wrong.

Monitor was completed two weeks before Virginia, but the Confederates elected to strike quickly. On March 8th 1862 the Virginia sailed under the Command of Franklin Buchanan, a veteran officer who had left the U.S. Navy to confront the Federal blockade force off Hampton Roads. During the battle she rammed and sank the large sailing Sloop of War USS Cumberland and shelled the sailing Frigate USS Congress, one of the Navy’s original six frigates until that ship caught fire and exploded during the night. The steam Frigate Minnesota, a sister ship of Merrimac and the flagship of the blockade force had run aground attempting to come to the aid of the two doomed ship and was at the mercy of Virginia. But tides and darkness caused Buchanan to withdraw for the night. March 8th was the “worst day in the history of the U.S. Navy. The Virginia sank two proud ships within a few hours – a feat no other enemy would accomplish until 1941. At least 240 bluejackets had been killed, including the Captain of the Congress – more than the navy suffered on any day of the war.”[16]

That night the tiny Monitor arrived and when Virginia steamed out on March 9th to complete the work she had begun the previous day, her crew saw a strange craft laying aside Minnesota. They did not realize that this was the new Union ironclad. As the Virginia approached Minnesota to finisher her off, the Monitor went into action. The ships fought a fierce engagement for several hours. The engagement was a draw and never fought again as neither side wanted to risk their only operational ironclad. Virginia had to be scuttled to avoid capture when Union forces captured Norfolk in May of 1862. However, the encounter had revolutionized naval warfare and doomed the graceful wooden wall of the sailing ships of the line and frigates. When the news of the action reached London the effect was shattering. The London Times commented:

“Whereas we had available for immediate purposes one hundred and forty-nine first class warships, we now have two, these being the Warrior and her sister Ironside. There is not now a ship in the English Navy apart from these two that it would not be madness to trust to an engagement with that little Monitor.” [17]

Designers on both sides experimented with various designs of ironclad warships. The Confederacy focused on building ironclad rams based on the Virginia, which featured a central armored casemate where all the ships guns were mounted. Eventually they completed twenty-one more such vessels which were used mostly in harbor defense activities. All of these ships faced construction challenges largely due to the shortage of iron plating, adequate propulsion systems and weapons. Some ships had armor plating consisting of railroad tracks which were bolted onto wooden casemates.


The U.S. Navy, with more shipyards and resources had a number of designs including the Eads river ironclads, the ironclad frigate USS New Ironsides and various types of “Monitors” featuring heavily armored revolving turrets designed by John Ericcson. Other designs were rejected for various reasons. While ironclads were the preferred type of ship, neither navy had the ability to build completely ironclad fleets and wooden ships still had a decided speed advantage over ironclads. Thus field-expedient protection was devised used which resulted in ships being protected by lumber, cotton and tin. However, by the end of the war the United States Navy had 58 monitors in operation. In addition to the monitor fleet another dozen or so ironclads of various types served in the U.S. Navy.

When the Ironclad Board of the United States Navy prioritized the types of ship to construct to meet the demands of the war, they rightly recognized that first priority had to be given to what we now call “the Brown Water Navy.” The Board determined that:

“Our immediate demands seem to require, first, so far as practicable, vessels invulnerable to shot, of light draught of water to penetrate our shoals, rivers, and bayous. We therefore favor the construction of this class vessels before going into a more perfect system of large iron-clad sea-going vessels of war.” [18]


The new designs which featured steam propulsion and armor protection instantly made all previous ships obsolete and by the 1880s these features would be incorporated in warship design by navies around the world. The effect was immediate in England where “After 1865 all the Royal Navy’s new ships were built of iron; the most modern of the old were cut down and iron clad.[19] France and Russia followed, but the United States, in its post war draw down allowed its fleet to crumble and it would not be until the 1880s that the first steel ships would be built to replace the now obsolete monitors and the remaining wooden steam frigates.


Two other naval developments from the Civil War still play an important role in naval warfare and strategy. Two were related to the modern submarine. The first that of a semi-submersible “torpedo boats” known as Davids, one of which disabled the massive USS New Ironsides, hitting the ironclad with a 60 pound charge on the tip of a spar torpedo mounted on its bow off of Charleston on October 5th 1863. The fifty foot long craft and two of her crew returned it to a heroes’ welcome. A Union torpedo boat under the command of Lieutenant William Barker Cushing, brother of Army Lieutenant Alonzo Cushing, a hero of “the Angle” at Pickett’s Charge, sank the ironclad CSS Albemarle on the Roanoke River with a spar mounted torpedo on October 27th 1864.

On February 17th the fully submersible CSS Hunley exploded a spar torpedo on the side of the USS Housatonic a steam sloop anchored off Charleston. The torpedo sank Housatonic and swamped the tiny Hunley taking her and her nine man crew to their watery grave. These early Confederate innovations spurred the development of submarines, something that the U.S. Navy pioneered and still leads the world in many ways. In many ways the submarine is the most deadly naval and strategic weapon system in the world today, and they trace their roots to the humble CSS Hunley, the first to sink a warship in combat.


The Hunley and Monitor remain today the most famous ships of the Civil War, each of which irrevocably changed the character of naval warfare for generations to come.

The last development was the development of what were then called torpedoes, but are now known as mines by the Confederate Navy. Authorized by the ever innovative Secretary of the Navy Stephen Mallory, these weapons were used to protect blockaded ports from Union Naval forces and by the end of the war these “infernal devices” had sunk or damaged forty-three Union warships.” [20]

The lessons learned from the battles along America’s Littorals demonstrate the importance of being able to conduct both blue water as well as actions along contested shorelines and inland waterways. Likewise they demonstrate to naval strategists the importance of not ignoring any means that a weaker opponent can use to defend his coastline. The surprise attack on the guided missile destroyer USS Cole by terrorists with an explosive laden craft on October 12th 2000 demonstrate the vulnerability of even the most modern warships to technology not much different than that used against New Ironsides, Housatonic and Albemarle in the Civil War.


[1] Keegan, John The Price of Admiralty: The Evolution of Naval Warfare Penguin Books, New York and London 1988 p.110

[2] Ibid. Keegan The Price of Admiralty pp.110-111

[3] Ibid. McPherson. The Battle Cry of Freedom p.382

[4] Currant, Richard N. God and the Strongest Battalions in Why the North Won the Civil War edited by Donald, David Herbert A Touchstone Book, Simon and Schuster New York 1996 p.33

[5] Ibid. McPherson. The Battle Cry of Freedom p.381

[6] Jones, Archer. Military Means, Political Ends in Why the Confederacy Lost edited by Boritt, Gabor, Oxford University Press, Oxford and New York 1992 p. 75

[7] Millet, Allan R. and Maslowski Peter For the Common Defense: A Military History of the United States, Revised and Expanded Edition The Free Press, New York 1994 p.220

[8] McPherson, James War on the Waters: The Union & Confederate Navies 1861-1865 p.96

[9] Ibid. Thomas, The Confederate Nation pp.129-130

[10] Ibid. McPherson War on the Waters p.97

[11] Ibid. Thomas, The Confederate Nation p.130

[12] Ibid. McPherson War on the Waters p.97

[13] Ibid. McPherson War on the Waters p.97

[14] Ibid. Millet and Maslowski For the Common Defense Revised and Expanded edition p.221

[15] Ibid. McPherson War on the Waters p.99

[16] Ibid. McPherson. The Battle Cry of Freedom p.376

[17] Ibid. McPherson. The Battle Cry of Freedom p.377

[18] _____________ The Daybook: Civil War Navy Special Edition – Technology U.S. Navy Naval History and Heritage Center retrieved from 16 January 2015 p.9

[19] Ibid. Keegan The Price of Admiralty p.111

[20] Ibid. McPherson Battle Cry of Freedom p.314

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