One-hundred and fifty years ago this week, an important component to the Federal efforts in the Western Theater came to the fore - the Mississippi River Squadron.
At the onset of war both the Army and Navy officers recognized the need for river gunboats complementing land operations along the Mississippi River and tributaries. The requirements for river operations - or "brown water" - differed significantly from the more traditional "blue water" navy's warship designs. On the Mississippi, the Navy needed light draft ships capable of maneuvering within the river channels. Likely tactical scenarios placed those gunboats in close proximity to enemy river defense batteries. So on that light draft, the boats had to carry structural bracing, armor, and heavy armament. Given these and other requirements, the ironclad river gunboats evolved almost independently of the contemporary "blue water" monitors.
Complying with immediate demands, the first river gunboats were conversions of existing river craft. Three riverboats became "timberclads" with the addition of heavy oak "armor" and a battery of naval guns. While useful for river patrols and action against less well defended points, these ships lacked the armor to deal with heavily fortified river bastions or the anticipated Confederate ironclads.
In September 1861 the Army acquired the ferry New Era for conversion into a timberclad. When turned over to the Navy for operations, Commander William D. "Dirty Bill" Porter renamed the ship USS Essex in honor of the famous War of 1812 era frigate commanded by his father. Porter also had light iron plating installed on the forward casemate and sides, making the Essex an "iron-plated" gunboat. She carried three 9-inch Dahlgren guns. While more formidable than the "timberclads," the Essex was not the all the Navy required. (Of note, the Navy completely rebuilt the Essex later in 1862 transforming the ship into a proper river ironclad.)
The solution came in the form of a class of armored gunboats, designed specifically for use on the rivers. Working from a description offered by the Army, naval chief constructor John Lenthall designed a vessel with very light draft. Lenthall then recommended the Army further consult with Samuel M. Pook, a shipbuilder of note, to refine the design. Pook would do more than just refine the design, . What emerged was a vessel uniquely adapted for riverine warfare.
Pook's design featured a hull 175 feet long and 50 feet wide, but drawing a draft of only 6 feet. A central casemate, not unlike later Confederate rams in appearance, housed a battery of heavy naval guns - three 8-inch, four 42-pdrs, and six 32-pdrs as designed. Five boilers, placed low in the hull, powered a central paddle wheel. Iron plate, some 2.5 inches thick, covered the forward casemate, sixty feet of the sides, and the pilot house. Because of the incomplete armor arrangements, these were not ironclads in the strict sense of the word. Although weighing 512 tons, Pook's gunboats could make nine miles-per-hour with a head of steam.
In August 1861, James Buchanan Eads won the contract to construct these vessels. Working at yards in Carondolet, Missouri and Mound City, Illinois, Eads' project move rapidly (mostly due to stiff penalties for late delivery!). First to roll off the ways was the USS St. Louis in mid-October at Carondelet. The USS Carondelet, USS Louisville, and USS Pittsburgh followed from the Missouri yards. The USS Cairo, USS Cincinnati, and USS Mound City came out of the yards in Illinois.
These seven "City-class" gunboats became the core of the Mississippi River Squadron. The St. Louis first went into action at Lucas Bend, just above Columbus, Kentucky, alongside the Essex, on January 11, 1862. Encountering three Confederate gunboats escorting a floating battery into position, the two Federal gunboats drove off their unarmored opponents. In the first engagement these "ironclad" gunboats established ascendency on the rivers.
During the first week of February, the Essex, St. Louis, Cincinnati, and Carondelet moved down the Tennessee River in support of a Federal force under General U.S. Grant. The Army didn't have much to do after the Navy's gunboats silenced Confederate defenses at Fort Henry. But assumptions about the gunboats effectiveness against shore defenses proved a bit premature. Later on February 14, at Fort Donelson on the Cumberland River four city-class gunboats could not pass the Confederate batteries. The problem was just as much tactical as technical.
Despite the Valentine's Day setback, the "brown water" gunboats figured prominently in Federal plans. The force continued to grow with the addition of more gunboats, such as the converted USS Benton at the end of February. In months to follow the gunboats pressed the Confederate defenses along the Mississippi. The Mississippi River Squadron provided the mobile striking force for the combined Army-Navy team that eventually drove the wedge through the Confederacy.