Built in 2007, by Nichols Brother Boatbuilders of Freeland, Washington (hull #S-151) as the Vigilant for Bay and Delta Maritime Services Incorporated of San Francisco, California.
In 2007, the tug was leased by Crowley Marine Services Incorporated of San Francisco, California. Where she retained her name.
Powered by two, Caterpillar 3516 diesel engines, with Rolls Royce z drives. For a rated 6,800 horsepower.
The tug's capacities are 70,840 gallons of fuel, 1,690 gallons of lube oil, 8,000 gallons of water, and 1,400 gallons of sewage.
Her towing gear consists of a single drum, towing winch, outfitted with 2.5(in) cable. And, a Markey hawser winch, mounted on her bow.