Built in 1970, by Southern Shipbuilding of Slidell, Louisiana (hull #88) as the Robert Alario for Nolty J. Theriot Offshore Incorporated of Golden Meadow, Louisiana.
In 1992, the tug was acquired by the Morania Oil Tanker Corporation of Staten Island, New York. Where she was renamed as the Morania No. 6.
In 2000, the Morania Oil Tanker Corporation merged with Penn Maritime Incorporated of Stamford, Connecticut. Where the tug was renamed as the Penn No. 6.
In 2012, Penn Maritime Incorporated was acquired by the Kirby Corporation of Channelview, Texas. Where the tug retained her name.
In 2017, the tug was phased out of active service. And, she was "laid up," at the Kirby Corporation's yard in Philadelphia, Pennsylvania.
Powered by two, sixteen cylinder, EMD diesel engines. Turning two, cast steel, fixed pitch, propellers. She is a twin screw tug, rated at 5,700 horsepower.
Her electrical service is provided by two 75kW generator sets. The tug's capacities are 174,618 gallons of fuel, 18,492 gallons of potable water, and 30,379 gallons of ballast.