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A peculiar fleet of shallow-draft, heavily armed gunboats patrolled the tributaries around Cairo, Ill., by the fall of 1861. These Yankee invaders had been pieced together using a variety of nascent naval technologies, and would have a profound impact on the Western Theater fighting. The gunboats’ immediate contribution was to establish tenuous control of waterways within volatile areas of Kentucky, Missouri and Tennessee. The fleet would play a pivotal role in supporting the Army and securing the Mississippi River by 1863.

The Yankee gunboats did not obtain the iconography of the USS Constitution or Monitor, yet their work in the nation’s heartland proved decisive during the war. It can be argued that the Union’s construction of a brown-water navy, with its symbolic effect on the local populace and military contingents, along with that technology’s important influence throughout the region, played a more decisive role than the Federal blockading fleet along the Atlantic Coast and Gulf of Mexico.

General in Chief George B. McClellan ordered U.S. Navy Commander John Rodgers to Cincinnati, Ohio, to begin the Union naval conquest of the West and “establish naval armament on the Mississippi and Ohio Rivers.” Though Rodgers had impeccable credentials, like most naval officers of the Civil War era he knew little of river operations. He had also been placed under the command of the Army, not a coveted post for a sailor.

The first order of business was to procure vessels suitable for river navigation. To expedite the process, Union authorities opted to convert some existing craft for riverine warfare while new boats specifically designed for the task were being constructed. Rodgers purchased three steamers in Cincinnati: A.O. Tyler, displacing 575 tons, 180 feet long with a 45-foot beam; Lexington, displacing 448 tons, 178 feet long with a 37-foot beam; and Conestoga, displacing 572 tons. All three were side-wheel steamships with thin plank housing covering their decks, which meant they would be very susceptible to enemy fire. Rodgers ordered 5-inch oak plank bulwarks applied to the steamships for protection against musket fire. He also ordered the boilers and steam fittings moved below deck. Armed with 8-inch Dahlgren guns, these timberclad or woodclad vessels were classified as “fourth raters” in U.S. Navy jargon. For the price of $62,000, the Union river navy—technically under the command of the War Department—had a fleet to begin offensive operations.

The three woodclads arrived at Cairo in early August 1861, making their presence known to the enemy almost immediately. Lieutenant Commander Seth Ledyard Phelps, aboard Conestoga, led a reconnaissance down the Mississippi River as far as New Madrid, Mo., and tried unsuccessfully to capture two Confederate steamers. A few days later, while patrolling the river near Commerce, Mo., Lexington was hailed by fleeing residents who informed Lieutenant Roger Nelson Stembel that 800 Rebels were on their way to take the town. After the gunboat fired just two warning shots in the direction of the Rebels, the would-be invaders reportedly fled to Benton, eight miles back from the river. In light of that development, Rodgers asked permission to place a gunboat permanently at Commerce. One Confederate officer confided in a town resident that the Southerners would fortify the town as soon as the gunboat left, but no action would be taken while it remained. Whether the hastily modified Union vessel was actually a tangible threat is debatable, but the perception that it was a floating fortress proved effective. The gunboats helped establish an early hegemony over the precariously held regions along the Mississippi.

In early September, Lexington and Conestoga sailed down the Mississippi escorting a Union Army advance along the Missouri coast. At Lucas Bend both gunboats opened fire on a large contingent of Confederate artillery and cavalry. The Rebel batteries maneuvered to get off good shots, but Phelps nimbly sailed the gunboats upstream and rendered the Confederate artillery movements futile. The Union vessel inflicted heavy casualties on the Southern cavalry, and also blasted troops firing from the brush with doses of canister. It was apparent to both sides that a steam-propelled flotilla, able to move against the current, put land-based artillery at a serious disadvantage.

The Union high command was quick to grasp the riverine fleet’s potential. The woodclads helped offset the shortage of Union troops in the area by patrolling the rivers, and helped deter major Confederate moves on the volatile border state of Missouri. Major General John C. Frémont ordered U.S. Navy Captain Andrew H. Foote up the Ohio River to Owensboro, Ky., to quell secessionist activity. At the end of October 1861, Conestoga headed 60 miles up the Cumberland River, where it engaged a Confederate detachment along the banks, scattering the Southerners and leaving seven dead on the field. The dominance of the Union Navy forces in these early engagements provided the sailors with tactical experience as well as confidence. Meanwhile the Confederates were growing increasingly wary of Yankee convoys.

The river patrols maintained an uneasy truce between unionists and secessionists. Commander Phelps, cruising the Ohio River, noticed mail steamers flowing freely between Indiana and Kentucky. Convinced those steamers were carrying supplies and, more important, information to Confederates occupying Bowling Green, Ky., Phelps asked permission to stop the mail deliveries, despite Rebel warnings that they would burn the steamers if the deliveries ceased. When Phelps heard that pro-Union residents of Caseyville, Ky., had been threatened, the gunboat commander warned the town authorities of severe consequences for violent reprisals—and the threats came to nothing. In fact, citizens of towns all along the Ohio were safeguarded due to the vigilance of the timberclad crews.

Meanwhile, veteran river pilot James Buchanan Eads was developing a different type of vessel for riverine warfare. Eads, an old friend of U.S. Attorney General Edward Bates, met with Abraham Lincoln’s Cabinet at the end of April 1861 and urged for the creation of shallow-draft armored gunboats. Eads agreed that the gunboats’ base of operations should be at Cairo, and he also offered his own salvage boat, Benton, for government service. Secretary of the Navy Gideon Welles ordered John Lenthall, chief of the Naval Bureau of Construction, to submit a design for the river ironclads.

Lenthall, whose experience lay with deep-water ships, was less than enthusiastic about this new project. When his premature design of a craft measuring 170 feet long and 28 feet wide, with a 5-foot draft, was handed to Samuel M. Pook, the naval architect realized the design’s narrow 22-foot beam was unnecessary for river operations. He instead proposed a vessel 175 feet long, with a 50-foot beam and a 6-foot draft. Pook also added a rectangular casemate to rise above the gun deck at an angle of 35 degrees, housing a single paddle wheel in the deck’s center as an alternative to the vulnerable side-mounted paddle wheel. A final protective measure was iron plating placed atop the casemate. When Cincinnati steam engineer A. Thomas Merritt was consulted about engine requirements for the new gunboats, he suggested installing two steam engines for each ship—and said he believed most of the machinery could be made to fit belowdecks.

Pook’s design was handed to Eads, who was awarded the government contract to build the boats after submitting a low bid of $89,600 each. The contract stipulated that he would deliver seven boats to Cairo by October 10, 1861, just 65 days later.

Eads’ experience proved invaluable as he ordered supplies and organized a workforce of competent ship builders. He leased two dry docks to begin construction: one at Union Ironworks, in Carondelet, Mo., near St. Louis; the other at Marine Railway and Shipyard, at Mound City, Ill., near Cairo. Within two weeks, he had gathered roughly 4,000 workers. He paid each man $2 daily for a 10-hour workday, with a 25-cent bonus for each overtime hour worked. A mandated seven-day workweek was put in place, with bonuses for workers who stayed for the entire project. Lights were installed at the docks to allow the constructors to work through the night.

Eads worked with Rodgers to figure out the final specifications for Pook’s boat design, also contending with delays in funding resulting from government bureaucracy, which frequently forced Eads to pay salaries and purchase supplies out of his own pocket.

Despite all that, Carondelet slid into the Mississippi River on October 12, 1861, followed by St. Louis, Louisville, Pittsburg, Cairo, Mound City and Cincinnati in the following weeks. The seven City-Class ironclads, named for the major Northern river cities and also referred to as Cairo-Class ironclads, would significantly bolster the Union naval presence in the West. Their hard outer casing and slow, methodical movements earned them the nickname “Pook’s Turtles,” or “Pook Turtles.”

The vessels were 175 feet long, with a beam of 51.2 feet and a draft of 6 feet. Their flat-bottomed hulls were laid across three keels, with the outer keels 10 feet apart from the center keel to support the wide beam.

Their casemates rose above the waterline at a 35-degree angle and were plated with 2½-inchthick iron plating. The iron plates, 13 inches wide by 8½ feet long, were locked together with overlapping lips. The wood oak planking of the casemates, to which the iron plates were bolted, was 24 inches thick forward and 12½ inches on the sides and aft. Due to weight restrictions on what could be placed above deck, three vital areas could not be adequately armored: the stern, the quarterdeck and the roof of the casemate, known as the hurricane deck.

A conical pilothouse was placed on the hurricane deck to protect the navigator. A single paddle wheel, 22 feet in diameter and 18 feet wide, was positioned in an opening in the vessel’s center, under the protection of the casemate. Five boilers, 3 feet in diameter and 25 feet long, with a brick furnace at each front end, were positioned below decks to power the vessels. Steam drums, which captured the excess steam created by the boilers, had to be placed above the boilers on the gun deck.

Each gunboat was armed with 13 guns: three on the bow, four on each side and two on the stern. Four of the guns were repurposed Army cannons that had been rifled, six were smoothbore 32-pounders and three were 8-inch Dahlgren shell guns. Together with the three timberclads, Benton (Eads’ old salvage boat, which would be converted to an ironclad in December 1861), and Essex (a ferryboat converted to an ironclad in November 1861), the new fleet gave U.S. forces a tactical advantage along the Western rivers, in addition to something perhaps more important: a symbolic show of force.

The first ironclad vessels evolved through the ideas, ingenuity and resourcefulness of Lenthall, Pook, Eads, Rodgers, Merritt and many other nameless maritime workers and engineers—all promoted by the U.S. War and Navy departments. The rapid nature of their design and construction was an admirable accomplishment, but it also ensured there were some very serious design flaws in the new gunboats.

As the designers assumed that the narrow confines of the rivers would result in a majority of frontal attacks, the bows were the most heavily armored portions of the gunboats. This left the vessels vulnerable in two respects: First, the top deck, or hurricane deck, was exposed to plunging fire from forts or artillery placed above it; second, the angled casemate was suited to deflect horizontal or broadside fire from other boats, but it wasn’t designed to deflect descending fire from higher elevations—a weakness the Confederacy quickly learned to exploit. What’s more, the concentration of armament up front and along the paddle wheel left the steam drum, which had to be raised above the boilers, and a considerable portion of the gun deck exposed to enemy fire.

Notwithstanding those flaws, the menacing Yankee flotilla caused its opponents great concern. Major General Leonidas Polk wrote to Confederate Secretary of the Navy Stephen R. Mallory requesting funds for three vessels that could be converted to armed gunboats, noting, “They are indispensable to our defenses.” And Brig. Gen. Lloyd Tilghman, worried about scant Confederate defenses along the Cumberland River, warned that the new Union ironclads “are very formidable; vastly more so than is generally considered.” Desperate to stop the iron turtles, Polk ordered obstructions placed in the Cumberland River to prevent navigation. Hulks were loaded with stones and sunk in the shallow passages. The Rebel leaders saw a glint of hope in early November 1861, when General Albert Sidney Johnston reported to Confederate Secretary of War Judah P. Benjamin that ironclad gunboats had been stopped by the obstructions in the Cumberland. A few days later, however, he reported that the gunboats had made it through once the river’s depth rose a few feet. The shallow-draft design proved its worth.

Federal ironclads Essex and St. Louis were dispatched to thwart an attempt by Confederate steamers to bring artillery farther north from Columbus, then occupied by Southern forces. Polk’s forces, confined to their redoubt overlooking the Mississippi courtesy of the Union river navy, were unable to advance farther.

As 1862 dawned, the Union Army—now poised to push into Tennessee—was aided significantly by the new fleet. Acting as a floating cavalry, the steamers provided invaluable reconnaissance role along the waterways. Armed with the information that the Southern army was moving guns into Fort Donelson, Commander Phelps recommended a swift assault on the garrison, especially considering that there were rumors of Confederate gunboats being constructed. With the Yankee flotilla arrayed throughout the waterways of the Upper Mississippi Valley, intelligence poured in. It wasn’t long before General Ulysses S. Grant and Flag Officer Foote began to advocate for an amphibious operation against Fort Henry and Fort Donelson.

The capitulation of those forts in the winter of 1862 shattered the Confederates’ Tennessee–Kentucky defensive line, clearing the way for the conquest of Nashville. The Battle of Fort Henry on February 6 was a complete naval triumph. General Tilghman confessed that once he saw the gunboat formation, “I had no hope of being able, successfully, to defend the fort against such overwhelming odds, both in point of numbers and in caliber of guns.” Tilghman ordered all his troops back to Donelson except for the artillerymen, who he hoped could delay the Federal fleet.

While the Union gunboats did not fare so well against the elevated artillery of Fort Donelson, their presence was still imperative for the Union victory. Confederate Colonel Jeremy Gilmer reported that the threat from the gunboats forced his exhausted gunners to man their stations day and night. Numerous Rebel officers commented on being demoralized by the Yankee fleet in their post-battle reports. Brigadier General Simon Bolivar Buckner’s argument for surrender, for example, was grounded in the flotilla threat. Union General Lew Wallace opined the gunboats were crucial to the victory, saying, “I fully believe it was the gunboats, the awful ironclads especially, that operated to prevent a general movement of the rebels up the river, or across it, the night before the surrender.”

Phelps’ raid up the Tennessee in February 1862 laid to rest any remaining doubts about the Union fleet’s efficacy. After Fort Henry fell, Phelps’ squadron penetrated 225 miles behind enemy lines before turning around. In some places, towns were evacuated before the Union boats appeared, while in others women and children cheered the Federals. At Florence, Ala., citizens pleaded with Phelps not to harm their town; he did not. On the return trip, when a small Federal party landed at Savannah, Tenn., to raid a Confederate camp, word of the gunboats’ approach preceded the landing, and the Federals found only abandoned military stores and ammunition.

In less than four days, three Union gunboats wreaked havoc up and down the Tennessee River, reaching into the Muscle Shoals area of northwest Alabama. One Southerner reported to Confederate Secretary of War Judah P. Benjamin that, with favorable water levels, nothing could stop a Federal gunboat invasion of northern Alabama or Mississippi. Three Confederate boats were captured, including one, Eastport, that would be converted into a Yankee ironclad. Jefferson Davis’ Navy Department, struggling to check the Yankee onslaught, lost six steamers that were burned and an estimated 250,000 square feet of lumber that was confiscated. The raid was a complete success, proving the Tennessee River was entirely in Union control.

After the fall of Donelson, the flotilla moved on to Clarksville, Tenn., finding Fort Defiance, the town’s river defense, abandoned. The formidable redoubt there, with cannons perched 200 feet above the river, could have caused problems for the gunboats, but news of the Union Navy’s approach had spread panic throughout the town. Clarksville’s leaders explained to Foote that the Confederates had retreated south and most citizens had already fled. The Yankee officer felt obliged to issue a proclamation of goodwill to reassure the remaining residents.

News of the approaching Union fleet spread panic through Nashville as well. Governor Isham G. Harris absconded to Memphis and advised the state legislature to do the same. Chaplain Robert F. Bunting wrote home that most of the occupants were planning to move out, “with the threat of the Yankee gunboats prompting the greatest fear.” Colonel Nathan Bedford Forrest’s cavalry had to quell food riots in the city. A Confederate rear guard burned Nashville’s railroad bridges and half constructed gunboats while the main Southern force retreated to Murfreesboro, Tenn. An unnamed Confederate captive confessed, “We had nothing to fear from a land attack, but the gunboats are the devil and we may as well look matters square in the face.”

As the pivotal year of 1863 dawned, the Union Navy’s tentacles stretched from Cairo up the Tennessee and Cumberland rivers and down the Mississippi, with only Vicksburg and Port Hudson still in Confederate hands. The hastily built Union flotilla had without doubt proved its mettle, not only as a tool of war, but also as a symbol of technological superiority. The boats helped to quell secessionist activity and assure Union sympathizers in the border states that they were being protected. The brown-water flotilla was pivotal to breaking the Confederacy’s Tennessee–Kentucky defensive line and eventually securing the entire Mississippi River.


Originally published in the February 2015 issue of Civil War Times. To subscribe, click here.