The "prefix" USASPB associated with the vessel is an error. The Army's designation of self propelled barges was Barge, Self Propelled (BSP). Smaller vessels simply had the designation "U.S. Army" and a number without being named. Some vessels were named but also bore the usual Army identification. The use can be seen in this photo of Col. William. A. Glassford in which "U.S. Army" is followed by "B.S.P. 2008" with Glassford underneath on the hull.
Priolo, Gary P. (5 June 2015). "USS Nashawena (YAG-35)". NavSource Online: Service Ship Photo Archive. Retrieved 4 February 2020.
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Naval History And Heritage Command. "Nashawena". Dictionary of American Naval Fighting Ships. Naval History And Heritage Command. Retrieved 4 February 2020.