Built in 1944, by Pensacola Shipyard and Engine Company of Pensacola, Florida (hull #12) as the ST-725 for the United States Army.
In 1945, the tug was acquired by the Jacksonville Utility Company of Jacksonville, Florida. Where the tug was renamed as the Utility.
In 1964, she was acquired by the St. Philip Coastal Towing Company of Tampa, Florida. Where the tug was renanmed as the Marilyn.
In 1965, the St. Philip Coastal Towing Company renamed the tug as the Mary St. Phillip.
In 1969, she was acquired by the Coastline Towing Corporation of Providence, Rhode Island. Where the tug was renamed as the Castle Hill.
In 1977, the tug was acquired by the Thames Towboat Company of New London, Connecticut. Where she retained her name.
In 1977, she was acquired by Winslow Marine Incorporated of Southport, Maine. Where she was renamed as the Marjorie J. Winslow.
In 2012, the tug was acquired by the Eastport Port Authority of Eastport, Maine. Where she was renamed as the Capt. Mackintire.
In 2015, she went out of documentation.
In 2018, the tug sank while under tow a few miles off the coast of Maine. She was powered by a single, Clark Brothers diesel engine. She was a single screw tug, rated at 750 horsepower.
Her electrical service is provided by two, 30kW generator sets. Driven by two, 4-71 diesel engines.
(Carel Boone, Steven M. Bryan Sr., Captain Brian Fournier)