Hercules, steam tugboat at Mare Island, Vallejo, United States

Hercules is a steel-hulled steam tug with a black hull, a yellow stripe and a pinkish-red band at the waterline, and a red upper section with round portholes. Its name is painted in yellow capitals on the side, a white life ring hangs on the red plating, and a black smokestack rises above a white wheelhouse. Below deck, a red metal workbench with a recessed sink and a tall red hand pump with a coiled rope show the working interior.

Built in 1907 by John H. Dialogue and Sons in Camden, New Jersey, for the Shipowners' and Merchants' Tugboat Company, Hercules reached San Francisco via the Straits of Magellan with her sister ship Goliah in tow. In 1924 the Western Pacific Railroad bought her to shuttle railroad car floats across San Francisco Bay from Oakland and Alameda, a role she held until 1957. The National Park Service took over her restoration in 1977, and in 1986 she was designated a National Historic Landmark.

The vessel shows how people in the early harbor era powered ships and the importance of steam technology to maritime commerce. Visitors can observe the working spaces that kept the ship operational and understand its role in the local shipping world.

The ship is permanently docked at Hyde Street Pier and can be visited by stepping aboard from the nearby street-level access. The best time to visit is during daylight hours in good weather, when you can see the ship's details and the water around it clearly.

In 1947 Hercules towed the hulk of the battleship Oklahoma to San Francisco Bay to be scrapped, a task noted in the vessel's records. The ship's triple-expansion steam engine and black hull with yellow lettering are what visitors see today.