Floating Dry Dock “Dewey”
This dry dock, which is capable of floating the largest battleship, was towed from Sparrow’s Point, Maryland, to Olangapo, Philippine Islands, a voyage of 13,000 miles. In operation, the dock is sunk by admitting water into its tanks until the ship can be floated in. The water is then pumped out and the dock with the ship inside rises to the proper level as shown.
U. S. Battleship “Mississippi” in Dry Dock at League Island
What are Dry Docks Like?
Although divers are able to go down under the water to examine the bottom of a ship while it is afloat, it is usually necessary to have it up on dry land when thorough inspections or repairs have to be made. So a berth something like a huge box stall in a stable is built, with the part where a horse would stand in the stall full of water, and a door, either made like swinging gates opening in the middle, or a caisson which is operated up and down like a window, at the end. The ship is floated into the dock and then after the door is shut to prevent any more coming in, all of the water is pumped out until the vessel rests on a lot of great big wooden blocks and supporting props with which the bottom and sides of the dock are lined. Supports are also placed between the vessel and each side of the dock. Then, when the work has been finished, and the ship is ready to go to sea, water is let back either by pumping it in or else by gradually opening the door at the end, and the vessel is able to float out into the river or harbor again.
Although all of the navy yards and some private corporations in this country have docks of this kind, they are not of as much importance here as in England, where they are used, without pumping out the water, for the loading and unloading of vessels, because of the very great rise and fall of the tides there straining and otherwise damaging ships tied up to ordinary docks.
There are nine important navy yards in the United States, located at Brooklyn, N. Y.; Boston, Mass.; Portsmouth, N. H.; Philadelphia, Pa.; Portsmouth, Va.; Mare Island, Cal.; New London, Conn.; Pensacola, Fla.; Washington, D. C., and Port Orchard, Wash.