Auxiliary floating drydock

Floating dry docks are able to submerge underwater and to be placed under a ship in need of repair below the water line.

Ballast pontoon tanks are flooded with water to submerge or pumped dry to raise the ship.

[1][2] At the start of World War II, the US Navy had only three steel auxiliary floating dry docks: To reduce travel time for repair work, over 150 auxiliary floating dry docks of different sizes were built during World War II between 1942 and 1945.

These newly built floating dry docks had a lift capacity of 400 to 100,000 tons.

After World War II some auxiliary floating dry docks were sold for private use and others were scrapped.

[4][2] During wartime, ships in continuous use need repair both from wear and from war damage such as from naval mines, kamikaze attacks, dive bombs and torpedoes.

Without remote on-location dry docks, months could be lost if a ship returned to a home port for repair.

Most auxiliary floating drydocks had provisions for the repair crew, including bunk beds, meals, and laundry.

Japanese pilots sometimes mistook empty auxiliary floating drydocks for aircraft carriers.

AFDB were needed to repair battleships, aircraft carriers, cruisers, and large auxiliary ships.

[4][29][30] Auxiliary Repair Docks were built by Pacific Bridge Company in Alameda, California.

ARD have an armament of two single Oerlikon 20 mm cannons, a bow and are sea worthy.

Eight were built at Wilmington, North Carolina, and five at San Pedro in Los Angeles, California.

All Medium Auxiliary Floating Dry Docks were converted to YFDs after World War II.