Built in 1975, by Halter Marine Services Incorporated of New Orleans, Louisiana (hull #487) as the Mister Marshall D. for the Jackson Marine Corporation of Houston, Texas.
The Jackson Marine Corporation was owned by the Halliburton Corporation of Houston, Texas. The company owned a total of ninety vessels. Consisting mainly of offshore tugs, and supply vessels. With some chemical transport and well stimulation vessels.
In 1985, Zapata Marine Service, Gulf Fleet Marine Incorporated, and Jackson Marine Services merged to form Zapata Gulf Marine Service Incorporated of Houston, Texas. Where the tug retained her name.
In 1992, Zapata Gulf Marine Incorporated merged with Tidewater Marine Incorporated of New Orleans, Louisiana. Where the tug retained her name.
In 1995, she was acquired by Dunlap Towing Company of LaConner, Washington. Where the tug was renamed as the Mike O'Leary.
Powered by two, Caterpillar 3516C diesel engines. With Reinjtes WAF 873 reduction gears, at a ratio 7.08:1. Turning two, 109(in) by 77(in), five bladed, stainless steel, fixed pitch propellers. For a rated 4,000 horsepower.
Her electrical service is provided by two, 75kW generator sets. Driven by two, Detroit Diesel 6-71 diesel engines. The tug's capacities are 99,000 gallons of fuel oil, 736 gallons of lube oil, 216 gallons of hydraulic oil, and 11,500 gallons of potable water.
The towing gear consists of a double drum, INTERcon towing winch. Outfitted with 2,500(ft) of 2(in) towing wire on the primary drum. And, 2,400(ft) by 1.75(in) towing wire on the the secondary drum.
(Captain Eric Takakjian, Kyle Stubbs)