Built in 1915, by the Great Lakes Towing Company of Cleveland, Ohio (hull #36) as the Missouri for the Great Lakes Towing Company of Cleveland, Ohio.
In 1983, the tug was chartered out as the Polk.
In 1984, she was returned to the Great Lakes Towing Company of Cleveland, Ohio. Where the tug was renamed as the Michigan.
In 1997, the tug was transferred to the Puerto Rico Towing and Barge Company of San Juan, Puerto Rico. A subsidy of the Great Lakes Group of Cleveland, Ohio. Where she was renamed as the Punta Tuna.
In 2004, she was acquired by Immel's Marine Incorporated of St. Thomas, Virgin Islands. Where the tug was renamed as the Superior.
In 2015, the tug was acquired by Cape Towing Caribbean Incorporated of Wilton Manors, Florida. Where she was renamed as the Cape Slattery.
In 1956, the tug was converted to diesel propulsion. Powered by one, EMD 12-567ATL diesel engine. She was repowered in 1966 with an EMD 12-567CA. With a Falk Reverse reduction gear, at a ratio of 2.98:1. Turning one, 84(in) by 80(in), four bladed, fixed pitch, stainless steel propeller, in a Kort nozzle. She is a single screw tug, rated at 1,640 horsepower.
(Isaac Pennock, Will Van Dorp, Paul Strubeck)