Despite their name, towboats typically pushed their loads of lashed-together barges (called a "tow"), rather than towing them. Because of this, they differed from passenger and freight riverboats in having a squared-off bow with large bumpers mounted on it. Well into the 20th century, stearnwheelers held an advantage over propeller-driven towboats, which needs a deeper draft and were more susceptible to damage. Eventually diesel power surpassed steam as it did on the nation's railways, and towboats are still the mucscle-men of the rivers today.
JuniorThe Junior is listed in the Wooldridge Steamboat Listing as having been built in 1899, and the only other reference I've come across is a government report that says that, while navigating the Chicago River on October 12, 1909, "the steamer Junior was struck by the Rush Street Bridge when about halfway through the draw sustaining damage amounting to about $300."
H.P. DilworthThe H. P. Dilworth was built in 1900 and was owned by the Dilworth Coal Company, who operated the Dilworth mine at Rice's Landing, a tiny borough in the southwestern corner of Pennsylvania, on the Monongahela River. H. P. Dilworth served on the Board of Directors for the mining company, and was the son of founder G. M. Dilworth.
Life was tough for a hard-working boat like the Dilworth. On August 13, 1904, the steamer suffered a collapsed lower flue in her starboard boiler near Homestead, Pennsylvania, which is also on the Monongahela. On February 2, 1907, the Dilworth was heading downstream on the river, pushing a lashup of coal-ladden barges (or "flats"; a typical load for the Dilworth was 10 to 14 flats) when it hit one of the piers of the Monongahela City bridge. The load broke loose, and two of the barges sunk.
Just over two weeks later, at 3:50am on February 18, the boat was positioned under the Dilworth Mine's tipple to take on coal for her boilers...but the coal flowed from the tipple faster than the crew expected, and before they had realized it, the boat was overloaded and started to sink. The river was fairly shallow, and only the main deck was swamped. A double crew was onboard at the time, and though some had to jump overboard, no one was lost. Two weeks later, the steamer was refloated, repaired and put back into service. Finally, the Annual Report of the Supervising Inspector General, Steamboat Inspection Service to the Secretary of Commerce for FY 1911 includes this entry under the year 1910:
January 19.—The towing steamer H. P. Dilworth, laid up at Rices Landing, Pa., with a watchman on board, caught fire about 10 a.m. from cause unknown and was totally destroyed. Estimated loss, $14,000.While on fire, the boat broke free of her moorings and floated at least a mile down the river, which was running high, before finally sinking.
Today, only one steam-powered sternwheel towboat has survived on America's waterways, the W.P. Snyder Jr., which was retired in 1955 and sold for $1 to the Ohio Historical Society, and is on display at the Ohio River Museum in Marietta, Ohio.