Built in 1967, by Mangone Shipbuilding Incorporated of Houston, Texas (hull #83) as the Hercules for Crowley Marine Services Incorporated of San Francisco, California.
She was the third Jupiter class tug constructed for Crowley Marine Services Incoprorated by the Mangone Shipbuilding Company.
In 2007, the tug was acquired by the Dunlap Towing Company of LaConner, Washington. Where she retained her name.
Powered by two, Caterpillar D-398-B diesel engines. With Lufkin reduction gears, at a ratio of 5.932:1 Turning two, five bladed, stainless steel, fixed pitch propellers. For a rated 2,000 horsepower.
Her electrical service is provided by two, Caterpillar D-330 generator sets. The tug's capacities are 45,000 gallons of fuel oil, 2,300 gallons of potable water, and 1,100 gallons of lube oil.
The tug's towing gear consists of a Skagit RB-90, double drum, towing winch. Outfitted with 1,600(ft) of 1.75(in) towing wire.