The barge was assembled by Zidell Explorations from scrapped ship steel in Oregon[2] in 1966 and fitted in San Francisco with a heavy 500-ton revolving crane made by Clyde Iron Works[3] to perform the heavy girder and deck-section lifts for construction of the 1967 San Mateo-Hayward Bridge.

[6] In the 1970s, Marine Boss was sold to J. Ray McDermott & Co., who had introduced the first 500-ton floating cranes for offshore platform construction in 1965[7] and were operating a similar fleet of barge-cranes under the McDermott Derrick Barge (DB) class.

[10] One of the tugboats returning Weeks 533 from Albany to New Jersey collided with the moored 750t crane barge N181 (aka Hank Hummel) near the Tappan Zee Bridge at night in heavy fog on 12 March 2016.

[11][12] Although the mate, who was at the helm of Specialist, initially jumped clear from the stricken tug onto N181, he returned to help free a trapped crewmate and all hands aboard subsequently drowned.

[13] The Clyde Iron Works Model 52-DE crane[14] can lift 500 short tons (454 t) using the main hoist on a 210-foot (64 m) boom at any point in the crane's revolution; capacity rises to 600 short tons (544 t) when using the main hoist oriented astern.