The sloop-of-war, protected by wood and driven purely by wind power, was a common sight early in the 19th century.

Screw sloops were fast and lightly armed steamships that used propellers to move through the water.

Steam frigates were larger and more powerful than steam sloops, although they sacrificed speed in exchange.

Double enders were steam-powered ships with steering capability on both ends, allowing them to move backward and forward without turning around.

The USS Lexington was one of the war's most illustrious timberclad gunboats, one of the longest serving vessels on the western rivers. She, along with the USS Tyler and the USS Conestoga, participated in the "Timberclad Raid" of 1862, capturing or forcing the destruction of nine Confederate ships along the Tennessee River in four days.

The invention of ironclads set a new standard in naval combat.

Monitor-class ironclads introduced heavy revolving turrets to the naval battlescape. The ship shown here, the USS Onandaga, sports an unusual additional turret.

The CSS Hunley, first launched in 1863, was the first military submarine in world history to sink an enemy ship in combat. Although the Hunley's success was extremely limited--and fatal to her crew--she forever changed the nature of naval warfare.