Built in 1964, by the Equitable Equipment Company Incorporated of Madisonville, Louisiana (hull #1314) as the Puerto Nuevo for Crowley Marine Services Incorporated of San Francisco, California.
In 1999, the tug was acquired by the McAllister Towing and Transportation Company of New York, New York. Where initially, the tug retained her name.
In 2008, the McAllister Towing and Transportation Company renamed the tug as the Neill McAllister.
In 2017, the tug was acquired by Greyfield Energy Services Limited of Trinidad and Tobago. Where she was renamed as the Grayfield T1.
She was powered by two, twelve cylinder, Caterpillar 12-D-398 diesel engines. With Caterpillar 3192 reduction gears, at a ratio of 5.31:1. She is a twin screw tug, rated at 1,800 horsepower.
Her capacities were 34,000 gallons of fuel oil, 500 gallons of lube oil, and 4,500 gallons of potable water.