Edward M. Cotter is considered to be the oldest active fireboat in the world and was designated a National Historic Landmark in 1996.

Construction was started on March 24, 1900, and she was christened on September 1, 1900, by Lucia Virginia Malone, the nine-year-old daughter of one of the city's fire commissioners.

William S. Grattan was powered by two Babcock & Wilcox coal-fired boilers with steam engines rated at 900 horsepower (670 kW).

The ship was also equipped with three double action steam pumps that supplied water at 9,000 US gallons per minute (0.57 m3/s; 7,500 imp gal/min) to the three fire monitors used for firefighting.

Also, the city of Buffalo had shoreline hookups to allow the fireboats to serve as floating pumping stations supplying high pressure water to a fire hydrant system that covered the downtown area.

Chief Engineer Thomas Lynch of William S. Grattan lost his life after abandoning ship and seven other crew members were injured.

[15] The unattended boilers on William S. Grattan soon ran dry and exploded, leaving the ship burned out to the waterline and heavily damaged.

Also, the pilot house was raised to the upper boat deck level and a fixed turret tower with a fire monitor was constructed on the stern of the ship.

[3] After the refit Edward M. Cotter mounted five fire monitors capable of pumping 15,000 US gallons per minute (0.95 m3/s; 12,000 imp gal/min).

[21] Two days previously, on October 5, 1960, a set of grain elevators caught fire at the eight-story Maple Leaf Milling Company.

Escorted by a United States Coast Guard cutter, because she had never needed navigational equipment of her own, Edward M. Cotter proceeded across the international border.

This mission is said to have been the first instance that a United States fire boat had crossed an international border to help authorities in another country.

[13] Edward M. Cotter also assisted the disabled United States Coast Guard cutter Ojibwa during the winter of 1983.

Edward M. Cotter towed Ojibwa to her base in Buffalo and helped keep her afloat while repairs were made.

A non-profit group named "Friends of the Cotter", founded in 2005, has been running fund-raising events to overhaul Edward M.