The original "W. T. Preston" was a 163-foot, wooden-hulled vessel which pulled snags, performed light dredging, and otherwise worked the waters of Puget Sound until 1939; when, the Army Corps of Engineers built a new superstructure atop a welded steel hull and transferred the stern wheel, main engines, smokestack, foredeck equipment, and other items onto the second "WT Preston". The mission of "W. T. Preston" changed throughout the years. As rivers were used less and less for transportation of goods, "W. T. Preston" began to dredge, fight fires, and perform other general work. Throughout her commission, she even retrieved a sunken military bomber, and several automobiles.