Once in San Francisco the crews often deserted the ships. The ship owners found little cargo of value to ship back to the East Coast out of California and the ships often went back in ballast with a cargo of useless rocks. Since many of the ships were older and required expensive maintenance and crews were very hard to find and/or very expensive many hundreds of vessels were simply abandoned or sold at very low cost in Yerba Buena Cove. Others were converted into store ships or floating warehouses, stores, hotels, prisons, etc.. Some abandoned ships were bought cheap, filled with ballast and sunk on the mud flats at high tide to enlarge the available wharves and docks. The ships were typically stripped of her upper works and all usable fittings by one of San Francisco's many marine salvage firms of Gold Rush days and then covered with debris and sand as developers filled in the mud flats on the bay and built wharves out to deeper water to accommodate docking ships. By 1857 nearly all abandoned shipping in the Yerba Buena Cove that had not been re-used was sent to a marine salvage or ship breaking firms where all usable fixtures, anchors, etc. were removed, the copper bottom (about of copper) salvaged and the timbers were removed and set aside for other uses. The rapidly expanding city of San Francisco needed room to store all of the incoming goods and much larger dockside facilities—there were none when California was annexed. There initially was not time to build adequate warehouses, wharves, docks on the water front. In early September 2001, the "General Harrison", was discovered at the northwest corner of Battery and Clay streets during construction. She was built in 1840 in Newburyport, Massachusetts, and abandoned sometime before 1850 and turned into a store ship (warehouse). She was long, wide, in depth and displaced 409 tons. She was burned to the water line in one of San Francisco's early fires. The remains, including some of the stores on board, were filled with sand and built over.