Brown water navy

The term brown-water navy refers in its broadest sense to any naval force capable of military operations in fluvial or littoral environments, especially those carrying heavy sediment loads from soil runoff or flooding. It originated in the United States Navy during the American Civil War, when it referred to Union forces patrolling the muddy Mississippi River, and has since been used to describe the small gunboats and patrol boats commonly used in rivers, along with the larger "mother ships" that supported them. These mother ships include converted World War II-era LCMs and LSTs, among other vessels.

Brown-water navies are contrasted with seaworthy blue-water navies, which can independently conduct operations in open ocean.

After losing its blue-water fleet in the Battle of Copenhagen (1807), the kingdom of Denmark-Norway quickly built a brown-water navy. The partial successes of the resulting Gunboat War were undone by land invasion.

The term brown-water navy originated in the American Civil War, of 1861–1865. As a blueprint for the "strangulation" of the Confederate States of America, Winfield Scott's Anaconda Plan called for a two-pronged approach by first blocking the South's harbors and then pushing along the Mississippi River, effectively cutting the Confederate territory in two while also robbing the South of its main artery of transport. The U.S. Navy was assigned the blockade of the seaports, while a new force of gunboats and river ironclads, together with regular army units, would take, or at least lay siege to, the Confederate forts and cities along the Mississippi. In the early days of the war, U.S. Army built and crewed these boats, with the naval officers commanding them being the only direct connection to the U.S. Navy. By the autumn of 1862, the boats and their mission were transferred to the Department of the Navy. Because of the river's murky brown water, the ships that participated in these Mississippi campaigns were quickly referred to as the brown-water navy, as opposed to the regular U.S. Navy (which was henceforth referred to as the deep-water or blue-water navy).

...
Wikipedia