The W.T. Preston’s steam-powered engines were first installed on the Swinomish in 1914, then transferred with most of the machinery to the new wood-hulled W.T. Preston in 1929 and to her steel-hulled replacement in 1939. Originally fired with cordwood, the steam boiler was later converted to burn heavy fuel oil, and modern burners installed in 1967 used lighter diesel fuel, greatly improving combustion and reducing air pollution. Typical operating speed in smooth water was 6 to 7 knots and, in mildly rough water, 3 to 5 knots, while the paddlewheel churned at 16 revolutions per minute in normal cruising. The U.S. Army Corps of Engineers operated steam-powered sternwheeler snagboats in rivers from Blaine to Olympia to keep the region’s tributaries clear of navigational hazards, and the W.T. Preston was the last of the sternwheelers.