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The ''Milwaukee''-class monitors were a class of four riverine ironclad monitors built during the American Civil War. Several supported Union forces along the Mississippi River in mid-1864 before participating in the Battle of Mobile Bay in August. ''Chickasaw'' and ''Winnebago'' bombarded Confederate coastal fortifications during the battle and during subsequent operations as well as engaging the ironclad ''Tennessee II''. The other two ships arrived at Mobile Bay after the battle and all four supported the land attacks on Mobile in March–April 1865. ''Milwaukee'' struck a torpedo during this time and sank. The surviving three ships were sold in 1874; ''Chickasaw'' was converted into a ferry and survived until 1944 when she was scuttled. Her wreck was discovered in 2004. ==Design and description== The ''Milwaukee''-class monitors had their origin in an order from Gideon Welles, Secretary of the Navy, to Commodore Joseph Smith, Chief of the Bureau of Yards and Docks, on 16 April 1863 to recommend four more river ironclads that could mount four Dahlgren guns on a draft no more than . James Eads received the contract to build four iron-hulled, twin-turreted ironclads, partly due to the influence of Missouri Congressman Frank P. Blair, Jr.〔 Eads retained two of the ships, but subcontracted the other two to other builders.〔Canney, pp. 114, 150〕 The ''Milwaukee''-class ships were long overall and had a beam of .〔 They had a depth of hold of 〔Canney, p. 114〕 and a draft of six feet. The ships were 970 tons burthen〔 and displaced .〔Chesneau & Kolesnik, p. 123〕 They were powered by two 2-cylinder horizontal non-condensing steam engines,〔 each driving two propellers,〔 using steam generated by seven tubular boilers.〔 The engines were designed to reach a top speed of . They had a bore of and a stroke of .〔Canney, p. 115〕 They carried of coal.〔 The ships' main armament consisted of four smoothbore, muzzle-loading 11-inch Dahlgren guns mounted in two twin-gun turrets.〔 The fore turret in each ship, except , was designed by Eads while the aft turret was the standard Ericsson design used in most Union monitors. Unlike the latter, which rested its entire weight on a central spindle that had to be elevated in order for the turret to rotate, Eads' design better distributed its weight because it rested on a number of ball bearings underneath the outer edge of the turret. The structure of the Eads turret extended down to be bottom of the ship and the entire structure rotated. The guns in the Eads turret were mounted on a steam-powered platform that moved up and down, so that the guns could be reloaded below deck, safe from enemy interference. Both turrets used steam engines to rotate, but the Eads design also used it to power virtually every function in the turret, including running out the guns, absorbing the recoil from firing, and opening the gun ports to allow the guns to fire. The ability to adjust the level of the turret floor doubled the elevation of the guns to +20° compared to the +10° allowed in an Ericsson turret. Another advantage was that the Eads turret only required a crew of six men, far fewer than the Ericsson design.〔Canney, pp. 114–16〕 Each gun weighed approximately . They could fire a shell up to a range of at an elevation of +15°.〔Olmstead, et al, p. 90〕 The cylindrical turrets were protected by eight layers of wrought iron plates above the deck. Below the deck the side of the Eads turret was only a single layer thick and had holes through which the guns were loaded. The sides of the hull consisted of three layers of one-inch plates, backed by of pine. The deck was heavily cambered to allow headroom for the crew on such a shallow draft and it consisted of iron plates thick. and had an additional layer of armor to give them a total of . The pilothouse, positioned behind and above the fore turret, was protected by of armor.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Milwaukee-class monitor」の詳細全文を読む スポンサード リンク
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