Built in 1974, by McDermott Shipyard Incorporated of Morgan City, Louisiana (hull #187) as the Robin V for the Robin International Towing Company of Harvey, Louisiana.
In 1983, the tug was acquired by Crowley Marine Services Incorporated of San Francisco, California. Where she was renamed as the Sea Robin.
She was the first Sea Robin class tug for Crowley Marine Services.
In 2011, the tug was acquired by the Dunlap Towing Company of LaConner, Washington. Where she was renamed as the Polar Endurance.
In 2018, the tug was phased out of active service, and was "laid up" on the Duwamish River in Seattle, Washington.
Powered by two, Caterpillar 3606-3 diesel engines. With Lufkin RHS 2524 reduction gears, at a ratio of 3.972:1. Turning two, four bladed, stainless steel, fixed pitch propellers. For a rated 5,000 horsepower.
Her electrical service is provided by two, 75kW generator sets. Driven by two, Detroit 6-71 diesel engines. The tug's capacities are 75,000 gallons of fuel oil, 4,104 gallons of lube oil, and 11,000 gallons of potable water.
The towing gear consists of an INTERcon DD-225, double drum, towing winch. Outfitted with 2,000(ft) of 2.25(in) wire on both drums.