Union unpreparedness did not prevent a “paper blockade” of Southern ports. Official proclamations were published in Southern papers, and ships were dispatched to give due notice of the Union policy to neutrals and Confederates in the most populous of 189 harbors, rivers, and inlets along 3,500 miles of Southern coast.
An “effective blockade”—actually preventing entry and exit at Southern ports—would require 600 ships. As the Union tripled the navy's manpower with a call for 18,000 volunteers, 21 percent of U.S. naval officers joined the fledgling Confederate navy.
Mobilization on that scale required new navy secretary Gideon Welles to appoint Gustavus V. Fox assistant secretary for operations to work with the chief clerk and naval bureaus. Boards to plan blockade strategy and ironclads soon followed. Construction was authorized for 52 new ships: ironclad “turtles,” monitors, and steamers; 136 vessels were acquired, including merchantmen, tugs, and ferries.
The blockade strategy evolved as four blockading squadrons: North Atlantic on the Virginia–North Carolina coast; South Atlantic from Charleston and Savannah to Key West; East Gulf from Key West to St. Andrews Bay; and the West Gulf from Pensacola past Mobile, New Orleans, and Galveston to the Rio Grande. Union commanders David Farragut, David Dixon Porter, and John Dahlgren were especially successful, and within a year after the Blockade Proclamation, the Union had recaptured Norfolk, Pensacola, and New Orleans as the Anaconda plan tightened the blockade.
Union blockaders pursued blockade runners and searched out any vessels to be found in coastal and inland waters, always examining ships' papers to distinguish neutrals from Confederates. Blockade activities came to include destroying sand forts and saltworks ashore; receiving and transferring refugees, escaping slaves, and Confederate deserters; volunteering medical aid, purchasing supplies, and hiring local civilians.
This change in naval operations brought endless frustrations of operating seagoing vessels in shallow coastal waters. Pursuit of blockade runners often ran them aground, costing officers and crew the prize money awarded for captures. Mastering new steam and ironclad technologies placed complex demands on crews; added peril came from engaging new Confederate technologies, including ironclad ships, mined harbors and rivers, spar torpedo boats, and the primitive submarine Hunley at Mobile and Charleston. Sheer numbers of ships and men taxed Union naval resources—all told, 600 ships and 51,000 men at full strength, though a total of 120,000 were enlisted in 1861–65, at least 20,000 of them African Americans.
For all the promise of prize money, the blockades added increments of difficulty to a service already known for hardships and deprivation. Serving on sweltering ironclads and steamers or on marginally seaworthy vessels required increased attention to medical care, nutrition, and morale for volunteer citizen‐sailors. Malaria and yellow fever were special concerns in Southern waters. Temperance replaced the time‐honored daily grog ration. Boredom was an ever‐present enemy.
The Union strategy combined army‐navy expeditions on a large scale. The numbers engaged at Port Royal would not be matched until World War II. On the Potomac and the James Rivers, naval bombardment reinforced army field artillery. On the Mississippi, Tennessee, and Cumberland Rivers, combined army‐navy operations at Forts Henry and Donelson, at Vicksburg, and elsewhere added dramatic chapters to riverine history.
A civil war in home waters in no way diminished the navy's international role. The United States ran afoul of Britain's neutral rights when Confederate officials were removed from the British vessel Trent. Diplomatic tensions continued into the 1870s with U.S. claims against England because British‐built Confederate commerce raiders preyed upon American merchantmen and whalers. Despite those losses, the Union won one of history's most famous sea battles when the Kearsarge sank the Alabama in the English Channel.
The Union navy's response to the Civil War was heroic in its rapid mobilization and in combining a traditional blockade with innovative administration, operations, and weaponry.
[See also African Americans in the Military; Civil War: Military and Diplomatic Course; Fort Wagner, Siege of (1863); Hampton Roads, Battle of (1862); Mobile Bay, Battle of (1864); Navy, U.S.: 1783–1865; New Orleans, Siege of (1862); Vicksburg, Siege of (1862–63).]
Allen A. Gosnell , Guns on the Western Waters: The Story of River Gunboats in the Civil War, 1949.
Berne Anderson , By Sea and by River: The Naval History of the Civil War, 1962.
Rowena Reed , Combined Operations in the Civil War, 1978.
William M. Fowler, Jr. , Under Two Flags: The American Navy in the Civil War, 1990.
Robert M. Browning, Jr. , From Charles to Cape Fear, the North Atlantic Blockade Squadron During the Civil War, 1993.
Robert John Schneller , A Quest for Glory: A Biography of Rear Admiral John A. Dahlgren, 1994.
Ivan Musicant , Divided Waters, the Naval History of the Civil War, 1995.
Maxine T. Turner