ABSD-1 or Advance Base Sectional Dock -1 (to use the Navy’s correct nomenclature), was an enormous steel floating dry dock, that was shipped to Santo in in two separate convoys between July and October 1943. Capable of lifting ships displacing up to 90,000 tons, she was comprised of 10 separate sections, constructed in the United States between 1942 and 1943 at four separate shipyards – The Everett Shipbuilding Company in Everett, Washington; Chicago Bridge & Iron Company in Eureka, California and at Morgan City, Louisiana; and the Pollack-Stockton Shipbuilding Company in Stockton, California.
Floating dry docks capable of being moved to forward operational areas and capable of sustaining themselves without shore support had been investigated by the US Bureau of Ships for many years. And yet finding a design that would fulfill the needs of the Navy, particularly one featuring the lifting capacity for any ship in the fleet, had alluded designers for some years. When war was declared, it became apparent that floating dry docks were the key to maintaining the Navy’s operational capability, particulalry in the Pacific Theatre. So in early 1942 the necessary funds were made available and the project was authorised to proceed.