Military


CB-1 Alaska Class

The six Alaska class "large cruisers" were ordered in September 1940 under the massive 70% Expansion ("Two Ocean Navy") building program. The Navy had been considering since 1938 building ships of this entirely new type, intermediate in size between battleships and heavy cruisers. The new ships were to carry out what were then the two primary missions of heavy cruisers: protecting carrier strike groups against enemy cruisers and aircraft and operating independenly against enemy surface forces. Their extra size and larger guns would enhance their value in both these missions and would also provide insurance against reports that Japan was building "super cruisers" more powerful than U.S. heavy cruisers. In fact, Japan developed plans for two such ships in 1941 -- partly as a response to the Alaskas -- but never placed orders for their construction.

Proposed Heavy Cruiser - CA2-D was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 18 January 1940 and representing the largest size cruiser studied at this time, is for a ship of 38,700 tons standard displacement, with a main battery of twelve 12"/50 guns, a secondary battery of sixteen 5"/38 guns and a 212,000 horsepower powerplant for a speed of 33.5 knots. Ship's dimensions are: waterline length 850'; waterline beam 99'; maximum beam 104.5'; draft 31.5'. Anti-torpedo side protection included four internal bulkheads.

Proposed Heavy Cruiser - CA2-A was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 19 January 1940 and representing the smallest size cruiser studied at this time, is for a ship of 25,600 tons standard displacement, with a main battery of nine 12"/50 guns, a secondary battery of twelve 5"/38 guns and a 150,000 horsepower powerplant for a speed of 33.5 knots. Ship's dimensions are: waterline length 800'; waterline beam 85.1'; maximum beam 90'; draft 26.8'.

Heavy Cruiser Study - Scheme 2 was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 19 March 1940 and representing the smallest size cruiser studied in this series, is for a ship of 15,750 tons standard displacement, with a main battery of twelve 8"/55 guns, a secondary battery of twelve 5"/38 guns and a 120,000 horsepower powerplant. Ship's dimensions are: waterline length 700'; beam 72'; draft 23.5'.

Heavy Cruiser Study - Scheme 3 was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 20 March 1940, is for a ship of 17,300 tons standard displacement, with a main battery of six 12"/50 guns, a secondary battery of twelve 5"/38 guns and a 120,000 horsepower powerplant. Ship's dimensions are: waterline length 710'; beam 74'; draft 24.5'.

Heavy Cruiser Study - Scheme 4-A - "Convertible" was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 10 April 1940, is for a ship of 17,500 tons standard displacement, with a main battery of twelve 8"/55 guns (convertible to six 12"/50 guns in twin turrets, mounted in the 1st, 2nd and 4th barbettes), a secondary battery of twelve 5"/38 guns and a 120,000 horsepower powerplant for a speed of 33.1 knots. Ship's dimensions are: waterline length 710'; beam 74.5'; draft 24.7'. The design would be similar if fitted with six 12"/50 guns (Scheme 4B), but displacement rises to 17850 tons, draft increases to 25 feet, speed drops to 33.0 knots and the ship would trim down 2.4 feet by the head.

"12-Inch Gun Cruiser Study, CA2F" was a preliminary design plan prepared for the General Board as part of the process leading to the Alaska class (CB1-6) large cruiser design. This plan, dated 19 June 1940, is for a ship (CA2F) of 24,700 tons standard displacement and 28,300 tons trial displacement, with a main battery of seven 12"/50 guns, a secondary battery of twelve 5"/38 guns, and a 150,000 horsepower powerplant for a speed of 33 knots. Ship's dimensions are: waterline length 750'; beam 84'; draft 29'.

"Aircraft Carrier, Converted from 12" Cruiser (Class CB 1-6)" was a preliminary design plan prepared for the General Board as part of an exploration of carrier conversions of warship hulls then under construction. This plan, dated 3 January 1942, represents the conversion of Alaska class large cruiser hulls. It would have produced a ship similar in external appearance to the Essex (CV-9) class, but with lower freeboard, only two aircraft elevators, one catapult, and an 839' long flight deck somewhat offset to the port side. Aircraft capacity would have been lower than in the Essex design, with markedly reduced steaming endurance and modest anti-torpedo protection for the hull sides.

As built, the Alaskas were much closer to cruisers in design than to battleships or battlecruisers. They lacked the multiple layers of compartmentation and special armor along the sides below the waterline that protected battleships against torpedos and underwater hits by gunfire. Other typical cruiser features in their design were the provision of aircraft hangars and the single large rudder. Unlike other U.S. cruisers of the day, the hangars and catapults were located amidships, and the single rudder made them difficult to maneuver. On the other hand, the Alaskas' side armor covered more of the hull than was standard in contemporary U.S. cruisers.

Wartime conditions ultimately reduced the Alaska class to two ships. Construction of CB-3 through CB-6--along with the five Montana (BB-67) class battleships--was suspended in May 1942 to free up steel and other resources for more urgently needed escorts and landing craft. A year later, CB-4 through CB-6 were definitively cancelled. Hawaii (CB-3), however, was restored to the building program. Launched and partially fitted out, her construction was suspended and she was considered for conversion to a missile ship or command ship, but she was scrapped, still incomplete, in 1959.

After more normal construction periods, Alaska (CB-1) and Guam (CB-2) both arrived in the Pacific theater ready for action in early 1945. There they carried out both of their designed missions--carrier protection and surface strike--although their chances of encountering their primary intended opponents, Japanese heavy cruisers, had long since disappeared. Both returned to the U.S. soon after the war's end and, not finding a place in the postwar active fleet, remained in reserve until scrapped in 1960-61.



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