Crowley Marine Services INVADER class towing vessel BULWARK was built by the McDermott Shipbuilding Company in Morgan City, Louisiana in October 1976. The tug has an overall length of 136 feet, a beam of 36.5 feet and a depth of 19.2 feet. BULWARK is admeasured at 199 gross and 135 net tons. She is powered by two 20 cylinder EMD 645 EG marine diesel engines which provide 7200 horsepower to her twin propeller shafts. She is stationed in Valdez and performs ship assist work and general towing in Prince William Sound.