What was used by the US patrol coastal waters during the 1920s?

During the 1920s, the US utilized several types of vessels for coastal patrols, primarily employing motorized yachts and small patrol boats. The Coast Guard played a significant role in maritime law enforcement and search and rescue operations, often using revenue cutters and smaller craft for these purposes. Additionally, the Navy maintained a presence with destroyers and other small ships to ensure security along the coasts. These efforts were part of a broader strategy to protect American interests and maintain maritime safety during the post-World War I era.