Author: CaptainNemo Hello everyone, today, we are going to try something new. We have an article here from CaptainNemo about USS Alaska. Now, I am not into ships that much, but I think it’s really cool and I am looking forward to trying World of Warships, so – why the hell not. Enjoy! USS Alaska Series: Background and Design Before we begin, further articles will cover: “The Guns”, “Operational History” and “Comparison between other similar ships of the time.” And in the guns and comparison section I hope to discuss more of World of Warships. ~ CaptianNemo The Alaska class of “Large Cruisers” was originally conceived back in 1938 when the Bureau of Construction and Repair (BuC&R) conducted a comprehensive study of cruiser designs was conducted ranging from 6,000 ton to 38,000 ton cruisers. The Alaska Class would come to be termed as “cruiser-killers” by the Navy. As “cruiser-killers”, the Alaska Class was also designed protect carrier task groups (TG) and to operate independently and alone against enemy surface forces, namely they were designed to counter the threat of German and Japanese long range cruiser forces in both of these roles, that were built, were being built, or planned to be built and armed with 8 inch (203mm) guns which were the maximum allowed on Heavy Cruisers by the London Naval Treaty of 1930. President Franklin Delano Roosevelt (F.D.R.) himself influenced the creation and development of the Alaska Class which he felt was needed to counter the threat of German cruisers. F.D.R. had been previously the Assistant Secretary of the Navy between 1913-1920 and put his experience in that position from seeing political roadblocks on shipbuilding, political infighting and bureaucratic nonsense to streamline (speed up) the Navy’s procurement of new ships by, at times, acting as the “de facto” Secretary of the Navy or by personally getting involved with the design process and specification of new ship designs during his presidency. To cite the more extreme examples (Iowa Class) of involvement F.D.R. went to outside designers (BuC&R typically did all of the design work in-house) to draw up ship plans and then issued requests for such a ship with specifications that matched his personal designs. To help cover his tracks he had plans drawn up of ships not matching his specifications so that his design would be chosen after a careful review of the designs presented to the Navy. (Guns will be covered in another article) To do this the Alaska Class were given the ability to cruise up to 10,000 nautical miles at a speed of 15 knots @ Standard Displacement, and at Full Load, this cut 1 knot off their speed to obtain the same, 10,000nm, range. Engine efficiency for the Alaska Class was the result of nearly 10 years of steady development in metallurgy and naval designing. The Alaska Class used higher pressures, up to 634 psi, then previous designs which had been limited to 400 psi and 700° F in Mahan Class destroyers in 1933 due to concerns by engineers and by captains with increasing the operating temperatures and pressures. The Mahan Class were also the first to have reliable double-reduction gears on the steam turbines which helped to improve efficiency and reduce the overall total weight of the machinery needed to propel the ship to a given speed. The Navy standard, ~1935-36, by the time the Alaska Class was designed was 600 psi at 850° F with the boilers being capable of producing 634 psi and over speeding the turbines to produce 180,000 horsepower (versus a normal 150,000 horsepower) although damage would occur to the turbines if this was done for an extended length of time. As a result of this horsepower the Alaska Class could do 31-33 kts and when overloading the turbines do 35 kts for short periods. A common complaint was that the Class did not have the maximum amount of power (speed) then available as the ships could have been equipped with the same engineering setup as the Battleships and had 200,000 horsepower on tap all the time. This would have allowed the Alaska Class the ability to chase down nearly any other ship but at the time the Class, as designed, was to be used against ships that were believed to be slower than the Alaska’s so the additional weight in machinery was not considered to be sufficiently needed nor the additional cost expended when the designers were already trimming weight where they could without extremely sacrificing the protection of the ship. The armor for the Alaska Class is a compromise from several early design studies for a “Large Cruiser” showcasing the overall design of the ship and several variations of that design which shifted arms and armor and speed around into several designs. The final design chosen was to protect the ship from 8 inch guns fired from Heavy Cruisers and use the 12 inch (305mm) guns longer effective range to take the Heavy Cruisers out. Armor on the Alaska class was 9 inches thick tapering at the bottom to 5 inches thick (228.6 down to 127mm), inclined at 10°, and covered more of the waterline then was typical for a standard cruiser. The area protected by armor was designated as an percentage (%) base of the length of the waterline, which was standard practice during and before WW1. Deck armor varied as well and could be 1-3 inches thick (16mm to 76mm) depending upon the deck with the conning tower being armored as well 10.6 inches sides (269mm) and 5 inches (127mm) on the roof. The Alaska Class were designed to resist a 700lb TNT* warhead from a torpedo although variations of early designs were designed with resistance to a 500lb charge of TNT which was considered the minimum charge a capital ship should be designed to resist for and this was done as a proposed way to reduce the weight of the ship. At the time of the design it was not known that the Japanese Type-93 “Long Lance” Torpedo carried a 480 kg (1,100lb of Type 97 explosive**) warhead. The torpedo itself would not be noticed until intact examples would be found in 1943 and the full realization of the threat it posed noticed. Effectively the Alaska’s underwater defense was better than the standard Cruiser due to increased stiffening longitudinally and increased coverage of the main armor over a larger part of the ship but noticeably worse than that of a Battleship and the design for the Alaska did included a double bottom which was improved by careful design to give the ship similar protection to that of a previous sketch which had included a triple bottom. Continue reading →

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