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Schița exteriorului clasei Alaska
|Folosită de||Marina SUA|
|Disponibilizare||17 iunie 1944 - 17 februarie 1947|
|Constructor||New York Shipbuilding Corporation |
|Lungime||246,43 m (întreg)  |
241,25 (în apă)
|Pescaj||8,26 m (mediu)|
9,68 m (maxim)
|Deplasament||29 771 t (standard)|
34 253 t (încărcată la maxim)
|Sistem de propulsie||Turbine cu abur General Electric cu 4 arbori, transmisie cu dublă reducție, 8 cazane Babcock & Wilcox|
|Putere||153 000 CP (112 MW)|
|Viteză||de la 31 de noduri (58,2 km/h) la 33 de noduri (61 km/h)|
|Autonomie||22 000 km la 15 noduri (28 km/h) |
|Armament și protecție|
|Blindaj||Partea principală a centurii: 228,6 mm subțiindu-se până la 127 mm|
Turele: 325 mm frontal, 127 mm deasupra, 133-152 mm lateral și 133 în spate
Puntea blindată: 96,5 mm până la 101,6 mm
Puntea exterioară: 35 mm
A treia punte: 15 mm
Barbete: 279-330 mm
Turn de comandă: 269 mm cu 127 mm deasupra
|Armament||9 tunuri Mark 8 de calibru 50 (305 mm) (3 × 3)|
12 tunuri de calibru 38 (127 mm) cu scop dublu (6 × 2)
56 tunuri Bofors de 40 mm (14 × 4)
34 tunuri Oerlikon de 20 mm (34 × 1)
|Aeronave||2 × OS2U Kingfisher sau SC Seahawk[Nota 2]|
|Facilități aviatice||Hangar auxiliar situat la mijlocul vasului|
Clasa Alaska a constat în 6 crucișătoare comandate înainte de al Doilea Război Mondial pentru Forțele Navale ale Statelor Unite. Erau clasificate oficial ca și crucișătoare mari (CB), dar alții le-au considerat ca fiind crucișătoare de linie. Toate au fost numite după teritorii sau zone insulare ale Statelor Unite, simbolizând statutul lor mijlociu, între cuirasatele mai mari și crucișătoarele grele și ușoare mai mici.[Nota 3] Din cele 6 nave planificate, doar 2 au fost terminate, iar construcția celei de a treia a fost suspendată la 16 aprilie 1947, celelalte 3 fiind anulate. USS Alaska (CB-1) și USS Guam (CB-2) au servit Marina Statelor Unite în timpul ultimului an din al Doilea Război Mondial, fiind folosite la bombardamente și la escorta portavioanelor rapide. Au fost retrase din serviciu în 1947 după ce au petrecut doar 32, respectiv 29 de luni în acțiune.
Ideea unei clase de crucișătoare mari are origini la începutul anilor 30', când Marina SUA căuta să contracareze „cuirasatele de buzunar” din clasa Detuschland lansate de Germania. Planificarea navelor care, eventual, au devenit clasa Alaska, a început la sfârșitul anilor 30', după lansarea clasei Scgharnost de cuirasate a Germaniei și după zvonurile conform cărora Japonia construia o nouă clasă de crucișătoare de linie.[Nota 4] Pentru a servi ca „distrugătoare de crucișătoare”, capabile de a detecta și distruge aceste crucișătoare grele mai performante decât cum specifica Tratatul Naval de la Londra, clasei i-a fost oferite tunurile mari ale unui nou și scump proiect, blindaj limitat împotriva obuzelor de 304 mm, și motoare capabile de viteze de 31-33 noduri (58-61 km/h).
Dezvoltarea de crucișătoare grele s-a diminuat între Primul și al Doilea Război Mondial mulțumită condițiilor impuse de Tratatul Naval de la Washington și tratatele și conferințele ulterioare, unde Statele Unite, Regatul Unit, Japonia, Franța și Italia au decis să limiteze deplasamentul crucișătoarelor grele la 10.000 de tone și la un armament principal de 202 mm. Până la clasa Alaska, crucișătoarele Statelor Unite proiectate între cele 2 războaie au urmat acest model.
Impulsul inițial pentru proiectarea clasei Alaska a venit de la lansarea așa-numitelor „cuirasate de buzunar” ale Germanilor, la începutul anilor 1930. Deși nicio măsură nu a fost imediat luată, aceste gânduri au reînviat la sfârșitul aceluiași deceniu când rapoartele de spionaj indicau că Japonia planifica să construiască „super crucișătoare” care ar fi fost cu mult mai puternice decât crucișătoarele grele actuale ale Statelor Unite.[Nota 5] Marina a ripostat în 1938 când Biroul General a rugat Biroul de Construire și Reparare să conducă „un studiu comprehensiv al toate tipurilor de nave pentru a considera unui nou program de construcție la scară largă”. E posibil ca președintele Statelor Unite de la acea vreme, Franklin D. Roosevelt, să fi avut un rol principal în dezvoltarea clasei, luând în considerare dorința sa de a putea contracara abilitățile de raid ale crucișătoarelor japoneze și ale cuirasatelor de buzunar germane. Deși aceste afirmații sunt greu de verificat, ele au dus la specularea faptului că design-ul lor a fost „motivat politic”.
Un istoric a descris proiectarea design-ului clasei Alaska ca fiind „chinuitor” din cauza numeroaselor schimbări și modificări făcute aspectului navelor de către departamente și individuali. Ba chiar au fost 9 aspecte diferite, variind de la
One historian described the design process of the Alaska class as "torturous" due to the numerous changes and modifications made to the ship's layouts by numerous departments and individuals. Indeed, there were at least nine different layouts, ranging from 6,000-ton Atlanta-class anti-aircraft cruisers to "overgrown" heavy cruisers and a 38,000-ton mini-battleship that would have been armed with twelve 12-inch and sixteen 5-inch guns. The General Board, in an attempt to keep the displacement under 25,000 tons, allowed the designs to offer only limited underwater protection. As a result, the Alaska class, when built, were vulnerable to torpedoes and shells that fell short of the ship. The final design was a scaled-up Baltimore class that had the same machinery as the Essex-class aircraft carriers. This ship combined a main armament of nine 12-inch guns with protection against 10-inch gunfire into a hull that was capable of 33 knoti (61 km/h; 38 mph).
The Alaskas were officially funded in September 1940 along with a plethora of other ships as a part of the Two-Ocean Navy Act.[Nota 6] Their role had been altered slightly: in addition to their surface-to-surface role, they were planned to protect carrier groups. Because of their bigger guns, greater size and increased speed, they would be more valuable in this role than heavy cruisers, and would provide insurance against reports that Japan was building super cruisers more powerful than U.S. heavy cruisers.
Yet another drastic change was considered during the "carrier panic" in late 1941, when the Navy realized that they needed more aircraft carriers as quickly as possible. Many hulls currently under construction were considered for conversion into carriers. At different times, they considered some or all of the Cleveland-class light cruisers, the Baltimore-class heavy cruisers, the Alaska-class, and even one of the Iowa-class battleships; in the end, they chose the Clevelands, resulting in the conversion of nine ships under construction at the New York Shipbuilding Corporation shipyard as the light aircraft carriers comprising the Independence-class.
A conversion of the Alaska cruisers to carriers was "particularly attractive" because of the many similarities between the design of the Essex-class aircraft carriers and the Alaska class, including the same machinery. However, when Alaska cruisers were compared to the Essex carriers, converted cruisers would have had a shorter flight deck (so they could carry only 90% of the aircraft), would have been 11 feet (3,4 m) lower in the water, and could travel 8.000 nautical milei (15.000 km) less at 15 knoti (28 km/h; 17 mph). In addition, the large cruiser design did not include the massive underwater protections found in normal carriers due to the armor weight devoted to counter shell fire. Lastly, an Alaska conversion could not satisfy the navy's goal of having new aircraft carriers quickly, as the work needed to modify the ships into carriers would entail long delays. With this in mind, all planning to convert the Alaskas was abandoned on 7 January 1942.
Of the six Alaska-class cruisers that were planned, only three were laid down. The first two, Alaska and Guam, were completed. Construction of Hawaii, the third, was suspended on 16 April 1947 when she was 84% complete. The last three, Philippines, Puerto Rico, and Samoa, were delayed since all available materials and slipways were allocated to higher priority ships, such as aircraft carriers, destroyers, and submarines. Construction had still not begun when steel shortages and a realization that these "cruiser-killers" had no more cruisers to hunt—as the fleets of Japanese cruisers had already been defeated by aircraft and submarines—made the ships "white elephants". As a result, construction of the last three members of the class never began, and they were officially canceled on 24 June 1943.
Alaska and Guam served with the U.S. Navy during the last year of World War II. Similar to the Iowa-class fast battleships, their speed made them useful as shore bombardment ships and fast carrier escorts. Both protected Franklin(en) when she was on her way to be repaired in Guam after being hit by two Japanese bombs. Afterward, Alaska supported the landings on Okinawa, while Guam went to San Pedro Bay to become the leader of a new task force, Cruiser Task Force 95. Guam, joined by Alaska, four light cruisers, and nine destroyers, led the task force into the East China and Yellow Seas to conduct raids upon shipping; however, they only encountered Chinese junks. By the end of the war, the two had become celebrated within the fleet as excellent carrier escorts. During the war, both ships were part of Cruiser Division 16 commanded by Rear Admiral Francis S. Low, USN.
After the war, both ships served as part of Task Force 71, the designation for the U.S. Seventh Fleet's North China Naval Force. Its mission was to support the allied occupation of the Korean peninsula. This included executing various show-the-flag operations along the western coast of Korea as well as in the Gulf of Chihli. These naval demonstrations preceded Operation Campus, the amphibious landing of U.S. Army ground forces at Jinsen, Korea, on 8 September 1945. Subsequently, both ships returned to the United States in mid-December 1945, and they were decommissioned and "mothballed" in 1947. after having spent 32 months (Alaska) and 29 months (Guam) in service.
In 1958, the Bureau of Ships prepared two feasibility studies to explore whether Alaska and Guam could be suitably converted into guided-missile cruisers. The first study involved removing all of the guns in favor of four different missile systems. At $160 million, the cost of this proposed removal was seen as prohibitive, so a second study was initiated. The study left the forward batteries (the two 12-inch triple turrets and three of the 5-inch dual turrets) unchanged, and added a reduced version of the first plan on the stern of the ship. Even though the proposals would have cost approximately half as much as the first study's plan ($82 million), it was still seen as too expensive. As a result, both ships were stricken from the Naval Vessel Register on 1 June 1960. Alaska was sold for scrap on 30 June 1960, and Guam on 24 May 1961.
The still-incomplete Hawaii was considered for a conversion to be the Navy's first guided-missile cruiser;[Nota 7] this thought lasted until 26 February 1952, when a different conversion to a "large command ship" was contemplated. In anticipation of the conversion, her classification was changed to CBC-1. This would have made her a "larger sister" to Northampton(en), but a year and a half later (9 October 1954) she was re-designated CB-3. Hawaii was stricken from the Naval Vessel Register on 9 June 1958 and was sold for scrap in 1959.
Early in its development, the class used the US battlecruiser designation CC, which had been planned for the Lexington class. However, the designation was changed to CB to reflect their new status, "large cruiser", and the practice of referring to them as battlecruisers was officially discouraged. The U.S. Navy then named the individual vessels after U.S. territories, rather than states (as was the tradition with battleships) or cities (for which cruisers were named), to symbolize the belief that these ships were supposed to play an intermediate role between heavy cruisers and fully-fledged battlecruisers.
The Alaska class certainly resembled contemporary US battleships (particularly the North Carolina class, South Dakota class, and Iowa class) in appearance, including the familiar 2-A-1 main battery and massive columnar mast, and displaced twice that of the newest heavy cruisers (the Baltimore class). In weight, the ships were only 5,000 tons less than the London Treaty battleship standard displacement limit of 35,000 long tons (36,000 t), also longer than several treaty battleships such as the King George V and North Carolina-classes.
In design and armor the Alaska class are regarded as "large cruisers" rather than battlecruisers. Their design was scaled up from the treaty cruisers limited by the Washington, London and Second London naval treaties. In common with U.S. heavy cruisers, they had aircraft hangars and a single large rudder. Their armor lacked the underwater protection systems found on full-fledged battleships and even intermediate capital ships like the French Dunkerque and German Scharnhorst classes. This left the Alaskas virtually defenseless against torpedoes, as well as vulnerable to shells falling slightly short and continuing underwater to hit the hull. While the Alaskas had more side armor than other contemporary U.S. cruisers, their protection was only marginally capable of stopping 12" fire; they were vulnerable to battleship fire (14–16" fire) at any range.
In addition, despite being much larger than the Baltimore class, the numbers of secondary and anti-aircraft batteries of the Alaskas were similar. Whereas the Alaska class carried twelve 5"/38 caliber in six twin turrets, fifty-six 40 mm, and thirty-four 20 mm guns, the Baltimore class carried the same number of 5"/38s, eight fewer 40 mm, and ten fewer 20 mm., considerably fewer than new U.S. battleships that had ten (save for South Dakota (BB-57)) 5"/38 twin mounts while older refitted U.S. battleships had eight. Author Richard Worth remarked that when they were finally completed, launched, and commissioned, they had the "size of a battleship but the capabilities of a cruiser". The Alaska class was similarly expensive to build and maintain as contemporary battleships yet far less capable due to armor deficiencies, while only able to put up an anti-aircraft defense comparable to the much cheaper Baltimore cruisers.
Despite these cruiser-like characteristics, and the U.S. Navy's insistence on their status as cruisers, the Alaska class has been frequently described as battlecruisers. The official navy magazine All Hands said "The Guam and her sister ship Alaska are the first American battle cruisers ever to be completed as such." Some modern historians take the view that this is a more accurate designation because they believe that the ships were "in all senses of the word, battlecruisers", with all the vulnerabilities of the type. The traditional Anglo-American battlecruiser concept had always sacrificed protection for the sake of speed and armament—they were not intended to stand up against the guns they themselves carried. The Alaska's percentage of armor tonnage, 28.4%, was slightly less than that of fast battleships; the British King George V-class, the American Iowa class, and the battlecruiser/fast battleship HMS Hood(en) all had armor percentages between 32 and 33%, whereas the Lexington-class battlecruiser design had a nearly identical armor percentage of 28.5%. In fact, older battlecruisers, such as the Invincible (19.9%), had a significantly lower percentage. Armament-wise, they had much larger guns than contemporary heavy cruisers; while the Baltimore class only carried nine 8"/55 caliber Marks 12 and 15 guns, the Alaska class carried nine 12"/50 caliber guns that were as good as, if not superior to, the old 14"/50 caliber gun used on the U.S. Navy's pre-treaty battleships.
As built, the Alaska class had nine 12"/50 caliber Mark 8 guns mounted in three triple (3-gun) turrets, with two turrets forward and one aft, a configuration known as "2-A-1". The previous 12" gun manufactured for the U.S. Navy was the Mark 7 version, which had been designed for and installed in the 1912 Wyoming-class battleships. The Mark 8 was of considerably higher quality; in fact, it "was by far the most powerful weapon of its caliber ever placed in service." Designed in 1939, it weighed 55273 kg, including the breech, and could sustain an average rate of fire of 2.4–3 rounds a minute. It could throw a 520 kg Mark 18 armor-piercing shell 38.573 yarzi (35.271 m) at an elevation of 45°, and had a 344-shot barrel life (about 54 more than the much larger but similar 16"/50 caliber Mark 7 gun found in the Iowa battleships.).
The turrets were very similar to those of the Iowa-class battleships, but differed in several ways; for example, the Alaska class had a two-stage powder hoist instead of the Iowa class's one-stage hoist. These differences made operating the guns safer and increased the rate of fire. In addition, a "projectile rammer" was added to Alaska and Guam. This machine transferred shells from storage on the ship to the rotating ring that fed the guns. However, this feature proved unsatisfactory, and it was not planned for Hawaii or any subsequent ships.
Because Alaska and Guam were the only two ships to mount these guns, only ten turrets were made during the war (three for each ship including Hawaii and one spare). They cost $1,550,000 each and were the most expensive heavy guns purchased by the U.S. Navy in World War II.
The secondary battery of the Alaska class was composed of twelve dual-purpose (anti-air and anti-ship) 5"/38 caliber guns in twin mounts, with four offset on each side of the superstructure (two on each beam) and two centerline turrets fore and aft. The 5"/38 was originally intended for use on only destroyers built in the 1930s, but by 1934 and into World War II it was being installed on almost all of the U.S.'s major warships, including aircraft carriers, battleships, and heavy and light cruisers.
For anti-aircraft armament, the Alaska-class ships carried 56 × 40 mm guns and 34 × 20 mm guns. These numbers are comparable to 48 × 40 mm and 24 × 20 mm on the smaller Baltimore-class heavy cruisers and 80 × 40 mm and 49 × 20 mm on the larger Iowa battleships.
Arguably the most efficient light anti-aircraft gun of World War II, the 40 mm Bofors was used on nearly every major warship in the U.S. and UK fleets during World War II from about 1943 to 1945. Although they were a descendant of German and Swedish designs, the Bofors mounts used by the United States Navy during World War II had been heavily "Americanized" to U.S. Navy standards. This new standard resulted in a gun system set to English standards (now known as the Standard System) with interchangeable ammunition, simplifying the logistics situation for World War II. When coupled with hydraulic couple drives to reduce salt contamination and the Mark 51 director for improved accuracy, the 40 mm Bofors became a fearsome adversary, accounting for roughly half of all Japanese aircraft shot down between 1 October 1944 and 1 February 1945.
The Oerlikon 20 mm anti-aircraft gun was one of the most extensively used anti-aircraft guns of World War II; the U.S. alone manufactured a total of 124,735 of these guns. When activated in 1941, they replaced the 0.50" M2 Browning machine gun on a one-for-one basis. The Oerlikon gun remained the primary anti-aircraft weapon of the United States Navy until the introduction of the 40 mm Bofors in 1943.
|Alaska||Teritoriul Alaska||CB-1||New York Shipbuilding Corporation, Camden||9 septembrie 1940||17 decembrie 1941||15 august 1943||17 iunie 1944||Dezmembrată la Newark, 1961|
|Guam||Teritoriul Guam||CB-2||2 februarie 1942||12 noiembrie 1943||17 septembrie 1944||Dezmembrată la Baltimore, 1961|
|20 decembrie 1943||3 noiembrie 1945||N/A||Dezmembrată la Baltimore, 1960|
|Philippines||Federația Filipinelor||CB-4||N/A||N/A||Anulate în 1943|
|Puerto Rico||Teritoriul Puerto Rico||CB-5|
Hereafter referred to as: Morison, Victory in the Pacific
Adapted from the biographical sketch for Admiral Francis S. Low, Navy Biographies Branch, 23 July 1956; now part of the Modern Biography Files, Navy Department Library, Naval History & Heritage Command.
Hereafter referred to as: Bartow. From Hot War to Cold.
Part III - THE SURRENDER AND OCCUPATION OF KOREA, p. 111