Built in 2003, by Thoma-Sea Boatbuilders Incorporated of Houma, Louisiana (hull #121) as the HMS Frontier for Harley Marine Services Incorporated of Seattle, Washington
In 2006, the tug was leased by the Signet Maritime Corporation of Houston, Texas. Where she was renamed as the Signet Challenger.
Powered by two, Cummins QSK60 diesel engines. With two Rolls Royce US205 z drives. Outfitted with two, 84.6(in) by 78.6(in), four bladed NIBRAL propellers. For a rated 5,250 horsepower.
Her electrical service is provided by two, 95kW Cummins 6BTA5.9 generator sets. The tug's capacities are 107,000 gallons of fuel, 5,000 gallons of water, 500 gallons of lube oil storage, 500 gallons of hydraulic oil, and 1,000 gallons of dirty oil storage.
The towing equipment consists of a Markey DYSF-42, winch mounted on the bow. Outfitted with, 430(ft) of 2.25(in) Samson Saturn-12HMPE hawser. On the stern, she is outfitted with a single drum, 100 horsepower, CME Model 1M160-200D7-1257-130, towing winch. Outfitted with 2,000(ft) of 2(in) towing wire.