By 1882, Puget Sound's rivers were served by hundreds of steam paddlewheelers with such shallow drafts that people joked they could float on a heavy dew. Because their flat-bottomed hulls were easily punctured by submerged stumps and debris, Congress allocated $20,000 for a snagboat, and under the U.S. Army Corps of Engineers three steam-powered sternwheelers kept the region's tributaries cleared for 97 years: the Skagit, launched in 1885, the Swinomish in 1914, and finally the W.T. Preston in 1929 and 1939. Operating in rivers from Blaine to Olympia, these snagboats removed navigational hazards; small obstructions were grappled and hoisted aboard, large ones were sometimes dynamited, and the W.T. Preston collected 1,100 cubic yards of debris each year to be burned on a barge or deposited ashore. The Preston used a 70-foot boom and a 1¼-cubic yard clamshell dredging bucket, while fore and aft steel spuds were lowered through the hull to anchor it to the bottom, and crews located submerged hazards by sweeping riverbeds with cable suspended between two skiffs.