USS ABSD-4, later redesignated as AFDB-4, was a nine-section, non-self-propelled, large auxiliary floating drydock of the US Navy. Advance Base Sectional Dock-4 was constructed in sections during 1942 and 1943 by the Mare Island Naval Shipyard in Vallejo, California for World War II. With all ten sections joined, she was 927 feet long, 28 feet tall, and with an inside clear width of 133 feet 7 inches. ABSD-4 had a traveling 15-ton capacity crane with an 85-foot radius and two or more support barges. The two side walls were folded down under tow to reduce wind resistance and lower the center of gravity. ABSD-4 had 6 capstans for pulling, each rated at 24,000 lbf (110,000 N) at 30 ft/min (0.15 m/s), 4 of the capstans were reversible. There were also 4 ballast compartments in each section.

USS ABSD-2, later redesignated as AFDB-2, was a ten-section, non-self-propelled, large auxiliary floating drydock of the US Navy. Advance Base Sectional Dock-2 was constructed in sections during 1942 and 1943 by the Mare Island Naval Shipyard in Vallejo, California for World War II. Her official commissioning ceremony took place on 14 August 1943 with CDR Joseph J. Rochefort in command. With all ten sections joined, she was 927 feet (283 m) long, 28 feet (8.5 m) tall, and with an inside clear width of 133 feet 7 inches (40.72 m). ABSD-2 had a traveling 15-ton capacity crane with an 85-foot (26 m) radius and two or more support barges. The two side walls were folded down under tow to reduce wind resistance and lower the center of gravity. ABSD-2 had 6 capstans for pulling, each rated at 24,000 lbf (110,000 N) at 30 ft/min (0.15 m/s), 4 of the capstans were reversible. There were also 12 ballast compartments in each section.