USS ABSD-4, later redesignated as AFDB-4, was a nine-section, non-self-propelled,

large auxiliary floating drydock An auxiliary floating drydock is a type of US Navy floating dry dock. Floating dry docks are able to submerge underwater and to be placed under a ship in need of repair below the water line. Water is then pumped out of the floating dry dock, ...

of the

US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...

. Advance Base Sectional Dock-4 (Auxiliary Floating Dock Big-4) was constructed in sections during 1942 and 1943 by the

Mare Island Naval Shipyard The Mare Island Naval Shipyard (MINSY) was the first United States Navy base established on the Pacific Ocean. It is located northeast of San Francisco in Vallejo, California. The Napa River goes through the Mare Island Strait and separates th ...

Vallejo, California Vallejo ( ; ) is a city in Solano County, California and the second largest city in the North Bay region of the Bay Area. Located on the shores of San Pablo Bay, the city had a population of 126,090 at the 2020 census. Vallejo is home to the ...

for

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. With all ten sections joined, she was 927 feet long, 28 feet tall (keel to welldeck), 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

barge Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels ...

s. 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 at , 4 of the capstans were reversible. There were also 4 ballast compartments in each section. Building the Navy's Bases in World War II, History of the Bureau of Yards and Docks and the Civil Engineer Corps 1940-1946 Chapter IX, Floating Drydocks
/ref>
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World War II

The ABSD-4 floating drydock departed California in 1944 and made the voyage across the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

in convoys in 48 days. USS ABSD-4 sections were reassembled at

Espiritu Santo Naval Base Naval Advance Base Espiritu Santo or Naval Base Espiritu Santo, most often just called ''Espiritu Santo'', was a major advance Naval base that the U.S. Navy Seabees built during World War II to support the Allied effort in the Pacific. The base ...

Espiritu Santo Espiritu Santo (, ; ) is the largest island in the nation of Vanuatu, with an area of and a population of around 40,000 according to the 2009 census. Geography The island belongs to the archipelago of the New Hebrides in the Pacific region o ...

New Hebrides New Hebrides, officially the New Hebrides Condominium (french: link=no, Condominium des Nouvelles-Hébrides, "Condominium of the New Hebrides") and named after the Hebrides Scottish archipelago, was the colonial name for the island group ...

(now

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (french: link=no, République de Vanuatu; bi, Ripablik blong Vanuatu), is an island country located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of no ...

), in the South Pacific Ocean. Once assembled in the fall of 1944 she was move for operation at

Seeadler Harbor Seeadler Harbor, also known as Port Seeadler, is located on Manus Island, Admiralty Islands, Papua New Guinea and played an important role in World War II. In German, "Seeadler" means sea eagle, pointing to German colonial activity between 1884 an ...

(also called ''Port Seeadler''), at

Admiralty Islands The Admiralty Islands are an archipelago group of 18 islands in the Bismarck Archipelago, to the north of New Guinea in the South Pacific Ocean. These are also sometimes called the Manus Islands, after the largest island. These rainforest-co ...

in the

Bismarck Archipelago The Bismarck Archipelago (, ) is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea. Its area is about 50,000 square km. History The first inhabitants o ...

, to the north of

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

also called the ''

Manus Island Manus Island is part of Manus Province in northern Papua New Guinea and is the largest of the Admiralty Islands. It is the fifth-largest island in Papua New Guinea, with an area of , measuring around . Manus Island is covered in rugged jungles w ...

s'', after the largest island there, at

Manus Naval Base Manus Naval Base, Naval supply depot with piers and quonset Hut warehouses on September 18, 1945 Manus Naval Base was a number of bases built after the World War II Battle of Manus by United States Navy on the Manus Island and a smaller isla ...

. USS ABSD-4 sister ship USS '' ABSD-2'' also worked at Seeadler Harbor during the war. ABSD-4 repaired the large ships in the US Navy and

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...

during World War II. Able to lift 90,000 tons ABSD-2 could raise large ships like,

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

battleship A battleship is a large armored warship with a main battery consisting of large caliber guns. It dominated naval warfare in the late 19th and early 20th centuries. The term ''battleship'' came into use in the late 1880s to describe a type of ...

cruiser A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several roles. The term "cruiser", which has been in use for several hu ...

s, and large auxiliary ships, out the water for repair below the ship's

waterline The waterline is the line where the hull of a ship meets the surface of the water. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line (positioned amidships), that indi ...

. She was also used to repair multiple smaller ships at the same time. Ships in continuous use during war need

repair The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installa ...

both from wear and from war damage from

naval mine A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any ...

and

torpedoes A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

Rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

s and

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

s are best serviced on dry docks. Without ABSD-4 and her

sister ships A sister ship is a ship of the same class or of virtually identical design to another ship. Such vessels share a nearly identical hull and superstructure layout, similar size, and roughly comparable features and equipment. They often share a ...

, at remote locations months could be lost in a ships returning to a home port for repair. ABSD-4 had provisions for the repair crew, such bunk beds, meals, and laundry. ABSD-4 had

power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. Many p ...

ballast Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, ...

pump A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...

s, repair shops,

machine shop A machine shop or engineering workshop (UK) is a room, building, or company where machining, a form of subtractive manufacturing, is done. In a machine shop, machinists use machine tools and cutting tools to make parts, usually of metal or plast ...

s, and

mess hall The mess (also called a mess deck aboard ships) is a designated area where military personnel socialize, eat and (in some cases) live. The term is also used to indicate the groups of military personnel who belong to separate messes, such as the o ...

s to be

self-sustaining Self-sustainability and self-sufficiency are overlapping states of being in which a person or organization needs little or no help from, or interaction with, others. Self-sufficiency entails the self being enough (to fulfill needs), and a self-s ...

. ABSD-2 had two rail track moveable cranes able to lift tons of material and parts for removing damage parts and install new parts.
Some of the ships repaired: * USS ''Duluth'' (CL-87) repaired storm damaged on 10 June 1945 completed repairs 5 July, back in service. * USS ''New York'' (BB-34) repaired early March 1945, repaired propellers and repainted. Due to the USS ''New York'' 29 ft 7 in (9.02 m) draft with a full load, the battleship had to unload much of her

ammunition Ammunition (informally ammo) is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weap ...

and

fuel oil Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...

before entering AFDB-4. * USS ''Allen M. Sumner'' (DD-69) repaired on 20 Jan. 1945

Attacked

Near the end of the war on April 22, 1945 at 2pm a

Mitsubishi A6M Zero The Mitsubishi A6M "Zero" is a long-range carrier-based aircraft, carrier-based fighter aircraft formerly manufactured by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and was operated by the Imperial Japanese Navy from 19 ...

two seater plane piloted by Shimbo and Ensign Chuhei Okubo in the second seat, overflew Seeadler Harbor at 14,000 feet. They saw what they thought were two "aircraft carriers", but here actually empty floating dry docks ABSD-4 and ABSD-2. On April 27, 1945 at about 11:15pm a three

Nakajima B5N The Nakajima B5N ( ja, 中島 B5N, Allied reporting name "Kate") was the standard carrier-based torpedo bomber of the Imperial Japanese Navy (IJN) for much of World War II. Although the B5N was substantially faster and more capable than its Al ...

Japanese Zero The Mitsubishi A6M "Zero" is a long-range carrier-based fighter aircraft formerly manufactured by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and was operated by the Imperial Japanese Navy from 1940 to 1945. The A6M was ...

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

of the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

flying from Truk flew over ABSD-4, one plane dropped an

aerial torpedo An aerial torpedo (also known as an airborne torpedo or air-dropped torpedo) is a torpedo launched from a torpedo bomber aircraft into the water, after which the weapon propels itself to the target. First used in World War I, air-dropped torped ...

and it hit one of the pontoons tanks of ABSD-4 damaging the dry dock. At the time of the attacked ABSD-4 was repairing a

cargo ship A cargo ship or freighter is a merchant ship that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's seas and oceans each year, handling the bulk of international trade. Cargo ships are usu ...

Landing Ship, Tank Landing Ship, Tank (LST), or tank landing ship, is the naval designation for ships first developed during World War II (1939–1945) to support amphibious operations by carrying tanks, vehicles, cargo, and landing troops directly onto shore with ...

(LST) ship and a

seaplane tender A seaplane tender is a boat or ship that supports the operation of seaplanes. Some of these vessels, known as seaplane carriers, could not only carry seaplanes but also provided all the facilities needed for their operation; these ships are rega ...

ship. The seaplane tender was loaded with ammunition and under an emergency repair. She was repaired and returned to service. On the same day shortly after ABSD-4 was hit, ABSD-2 was hit by aerial torpedo into pontoon tank in section G, damaging the dry dock. ABSD-2 was repaired and returned to service. The

Post-war

After the war ABSD-4, ABSD-4 was reclassified AFDB-4 and was taken out of service. ABSD-4 was left in Seeadler Harbor off Lombrum Point at

Lombrum Naval Base Lombrum Naval Base, also known as HMPNGS ''Tarangau'' and formerly PNG Defence Force Base Lombrum, is a naval military base operated by the Maritime Operations Element of the Papua New Guinea Defence Force (PNGDF). It is located on Manus Island i ...

. ABSD-4 was officially decommissioned and struck from the US Navy register on April 15, 1989. ABSD-4 is now a shipwreck that is partially sunk. The outer walls of the ABSD-4 remain above the water line. She rest at Lombrum,

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

, GPS coordinates: .pacificwrecks.com AFDB-4 pacificwrecks.com, ABSD-4 - AFDB-4
/ref>

External links

pacificwrecks.com ABSD-4 and ABSD-2
* ttps://www.pacificwrecks.com/ships/usn/AFDB-4/2003/floating-dock.html pacificwrecks, ABSD-4 sunk side viewbr>pacificwrecks, ABSD-4 sunk front view

Youtube, BATTLESHIP USS IDAHO REPAIRED AT ESPIRITU SANTO in 1944 in USS Artisan (ABSD-1)1Youtube, August 15, 1944 mighty battleship Idaho at ABSD-1Youtube, Floating Dry Docks WWII

References

{{DEFAULTSORT:AFDB-4, USS World War II auxiliary ships of the United States Floating drydocks of the United States Navy 1943 ships

World War II

Attacked

Post-war

See also

External links

References