Shallow draft gunboats of the U.S. Navy sailed China's largest river for over 50 years before being officially organized as the Yangtze Patrol Force in August, 1921.
These ships protected U.S. citizens against the bandits and warlord forces in a turbulent China. In the mid-1920's, the internal struggle for power was accompanied by many acts of violence against foreigners. Units of the Yangtze Patrol, reinforced by destroyers and light cruisers from the U.S. Asiatic Fleet, steamed upriver to protect Americans and national interests.
Numerous confrontations occurred. When the situation stabilized an uneasy peace returned to the Yangtze valley, and the gunboats resumed anti-bandit activities. In the early 1930s severe floods along the entire river valley brought the gunboats and additional ships of the Asiatic Fleet into action again, this time in the humanitarian cause of aiding the millions of Chinese left homeless by the catastrophe.