Built in 1941, by the Gulfport Boiler and Welding Works of Port Arthur, Texas (hull #178) as the Leo for the Commercial Petroleum and Transport Company of Houston, Texas.
In 1956, the tug was acquired by the Port Arthur Towing Company of Port Arthur, Texas. Where she was renamed as the Gulf Fueler IV.
In 1971, the Port Arthur Towing Company renamed the tug as the Karen Fredeman.
In 1974, she was acquired by Hunter Flores Marine Incorporated of Freeport, Texas. Where the tug was renamed as the Karen.
In 1984, the tug was acquired by Karen Interests Incorporated of Bridge City, Texas. Where she retained her name.
She was later acquired by Superior Marine Service Incorporated of Bridge City, Texas. Where the tug retained her name.
The tug was then acquired by J and J Marine Incorporated of Galveston, Texas. Where she retained her name.
In 2004, she was acquired by J and M Marine Incorporated of Galveston, Texas. Where the tug was renamed as the Mystic.
In 2004, the tug was acquired by Virtual Marine Services Incorporated of Slidell, Louisiana. Where she retained her name.
In 2005, she was acquired by Coastal Marine Contractors Incorporated of Slidell, Louisiana. Where the tug retained her name.
In 2015, the tug was phased out of active service. And, was "laid up" at Slidell, Louisiana. The tug's current and or final disposition is unknown.
Repowered in 1964, the tug was powered by one, Caterpillar D353 diesel engine with a Twin Disc reduction gear at a ratio of 4.08:1. She was a single screw tug, rated at 450 horsepower.