Beginning in 1861, the Union Army had an active balloon corps. The Union Army Balloon Corp, led by presidential appointee Thaddeus S. C. Lowe, consisted of seven vessels, the largest at 32,000 cubic feet, used primarily for reconnaissance and surveilling Confederate troops. Most of these units were launched from ground bases; seaborne balloons had only been utilized once before, in 1849, when an Austrian vessel, Vulcano, launched a failed attempt to bomb Venice with manned hot air balloons.
The Union did not utilize a maritime vessel as a staging area until August of 1961. Lowe, with the assistance of fellow aeronaut John LaMountain, directed the construction of the first real aircraft carrier. The two rebuilt a coal barge, the George Washington Parke Custis, gutting the deck of its rigging to accommodate gas generators and a flight deck superstructure. The Custis was part of its own battle group, towed by the Stepping Stone and accompanying sloop Wachusett, the gunboats Tioga and Port Royal, and the armed transport Delaware during the course of its operational lifespan.
While it looks like little more than a manmade atoll in the middle of the Potomac, the Custis paved the way for the integrated operation of air and sea units. According to the Smithsonian's U.S. Centennial Flight Commission, she towed one of Lowe's balloons for 13 miles (21 kilometers) at an altitude of 1,000 feet (305 meters) while Lowe made continuous observations on Confederate troop movements. Other barges were converted to assist with the other military balloons: Apart from the Custis, LaMountain frequently used the deck of the small vessel Fanny to launch an observation balloon 2,000 feet (610 meters) over the James River in Virginia. The Smithsonian notes that word of the Americans' achievements even reached Europe, where the Prussian army sent Count Ferdinand von Zeppelin (yes, that one) to study Lowe's military balloons. While balloons were used again for aerial observation during World War I, the seaborne staging vessel fell into disuse until the use fixed-wing aircraft necessitated the development of the modern aircraft carrier.
An interesting side note on American military balloons in general: While Lowe was initially proposing the use of balloons to the Union army, LaMountain was also attempting to provide balloon services for the Union. He wrote to Secretary Cameron in 1861. According to the Smithsonian, the commander of the Union Forces at Fort Monroe, Major General Benjamin F. Butler, asked LaMountain for a demonstration. LaMountain made two successful ascents at Fort Monroe in July 1861 in his balloon Atlantic. The New York Times reported that LaMountain had been able to observe Confederate encampments, making the first aerial reconnaissance of the Civil War and also was the first to gather intelligence by free balloon flight rather than from a tethered balloon. With Lowe and LaMountain's aeronautical achievements, the history of American innovation in aviation precedes the Wright Brothers by at least a generation.
Top: A reconnaissance balloon is launched from the coal barge George Washington Parke Curtis, during the American Civil War. Credit: 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No. 76-17385).
Bottom: John Wise, John La Mountain, and Thaddeus Lowe fight a storm in the Atlantic. Credit: 2001 National Air and Space Museum, Smithsonian Institution (Videodisc No. 2B-30739).