Alaska-class cruiser

The Alaska-class were six large cruisers ordered before World War II for the United States Navy (USN), of which only two were completed and saw service late in the war. The USN designation for ships of the class was "large cruiser" (assigned the hull symbol of "CB"), a designation unique to the Alaska-class, and the majority of leading reference works refer to them as such. However, various other works have alternately described these ships as battlecruisers despite the USN having never classified them as such, and having actively discouraged the use of the term in describing the class. The Alaskas were all named after territories or insular areas of the United States, signifying their intermediate status between larger battleships (which were mostly named after states) and smaller heavy and light cruisers (which were named after cities).

The idea for a large cruiser class originated in the early 1930s when the USN sought to counter the "pocket battleships" being launched by Germany. Planning for ships that eventually evolved into the Alaska-class began in the late 1930s after the deployment of Germany's s and rumors that Japan was constructing a new large cruiser class, the B-65 "super cruiser." To serve as "cruiser-killers" capable of seeking out and destroying these post-treaty heavy cruisers, the class was given large guns of a new and expensive design, limited armor protection against 12-inch shells, and machinery capable of speeds of about .

Of the six planned, and were the only two to be commissioned; a third, Hawaii, was close to completion at the war's end and had its construction suspended on 16 April 1947, while the remaining three were cancelled. Alaska and Guam served with the USN for the last year of World War II as bombardment ships and fast carrier escorts. They were decommissioned in 1947 after spending only 32 and 29 months in service, respectively.

Background

Heavy cruiser development formalized between World War I and World War II due to the terms of the Washington Naval Treaty and successor treaties and conferences, where the United States, Britain, Japan, France, and Italy agreed to limit heavy cruisers to 10,000 tons displacement with 8-inch main armament. Up until the Alaska class, US cruisers designed between the wars followed this pattern.

The initial impetus for the Alaska design came from the deployments of Germany's so-called pocket battleships in the early 1930s. Though no actions were immediately taken, these thoughts were revived in the late 1930s when intelligence reports indicated Japan was planning or building "super cruisers" of the B-65 class that would be much more powerful than the current US heavy cruisers. The navy responded in 1938 when the General Board asked the Bureau of Construction and Repair to conduct a "comprehensive study of all types of naval vessels for consideration for a new and expanded building program". The US president at the time, Franklin Delano Roosevelt, may have taken a lead role in the development of the class with his desire to have a counter to raiding abilities of Japanese cruisers and German pocket battleships. While these claims are difficult to verify, others have speculated that their design was "politically motivated" rather than strategic.

Design

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. ranging from 6,000-ton anti-aircraft cruisers The General Board, in an attempt to keep the displacement under 25,000 tons, allowed the designs to offer only limited underwater protection such that they were vulnerable, by comparison with a battleship, to torpedoes and to shells that fell short of the ship. The final design was a scaled-up that had the same machinery as the s. This ship combined a main armament of nine 12-inch guns with protection against 10-inch gunfire into a hull that was capable of . Their role had been altered slightly: in addition to their surface-to-surface role, they were planned to protect carrier groups. This carrier escort capability was favored by Admiral King. 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 the American heavy cruisers. resulting in the conversion of nine ships under construction at the New York Shipbuilding Corporation shipyard as the light aircraft carriers comprising the .

A conversion of the Alaska cruisers to carriers was "particularly attractive" 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),

Construction

Of the six Alaska-class cruisers that were planned, only three were laid down. The first two, and , were completed by the New York Shipbuilding Corporation. Construction of , the third, was suspended on 16 April 1947 when she was 84% complete. 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".

Service history

thumb|right| during her shakedown cruise on 13 November 1944

and served with the U.S. Navy during the last year of World War II, forming Cruiser Division 16 commanded by Rear Admiral Francis S. Low, USN. Similar to the fast battleships, their firepower was useful in shore bombardment, and their speed made them excellent fast carrier escorts, a role for which the two had become celebrated within the fleet by the war's end. This included executing various show-the-flag operations along the western coast of Korea as well as in the Bohai Sea. These naval demonstrations preceded Operation Chromite, the amphibious landing of U.S. Army ground forces at Incheon, Korea, on 10 September 1950.

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. Early in its development, the class used the US battlecruiser designation CC, which had been planned for the . 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. being only 5,000 tons less than the Washington Treaty's battleship standard displacement limit of 35,000 long tons (36,000 t) (unchanged through the final naval treaty, the London Treaty of 1936). They were also longer than several treaty battleships such as the and North Carolina class.

In overall terms, the design of the Alaska class was scaled up from that of the (themselves the first cruisers in the US Navy to be designed without the limitations of the London Naval Treaty, and exceeding 10,000 tons standard displacement).

Armament-wise, the Alaskas had much larger guns than contemporary heavy cruisers; while the Baltimore class only carried nine 8-inch/55 caliber Marks 12 and 15 guns, the Alaska class carried nine 12-inch/50 caliber guns that were as good as, if not superior to, the old 14-inch/50 caliber gun used on the U.S. Navy's pre-treaty battleships. The Alaskas 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 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 (19.9%), had a significantly lower percentage.

Contributions to the debate over the classification and type of the Alaska class can be misleading or poorly considered and/or informed. For example, author Chris Knupp noted that while "other nations fulfilled the battlecruiser role by designing vessels like battleships, but stripped of armor and other features to gain speed", the United States "fulfilled the battlecruiser role by creating a larger, more powerful heavy cruiser...[whose] design already offered less armor and higher speed, but by enlarging the ship they gained the heavier firepower". Designed in 1939, it weighed including the breech, and could sustain an average rate of fire of 2.4–3 rounds a minute. It could throw a Mark 18 armor-piercing shell at an elevation of 45°, and had a 344-shot barrel life The Alaskas Mark 8 guns were the heaviest main battery of any cruiser of World War II, and as capable as the old 14-inch/45 caliber gun used on the U.S. Navy's pre-treaty battleships.

Anti-aircraft battery

thumb|upright|Crew of a [[Bofors 40 mm Automatic Gun L/60|40 mm Bofors gun on Alaska mount ammunition clips into the loaders of a pair of guns on 6 March 1945 during the Battle of Iwo Jima]]

Medium anti-aircraft armament (a key component of area air defence within a Task Group) on the Alaska-class ships was 56 x 40mm Bofors guns and for close-in air defence they carried 34 × 20 mm guns. These numbers may be compared with; 48 × 40 mm and 24 × 20 mm on the smaller Baltimore-class heavy cruisers, 60 x 40 mm and 36 x 20 mm on the larger battleship North Carolina at the end of the war, and 80 × 40 mm and 49 × 20 mm on the even larger Iowa-class battleships.

Ships in class

{| class="sortable wikitable plainrowheaders"

|+ List of Alaska-class cruisers

! scope="col" | Name

! scope="col" class="unsortable" | Namesake

! scope="col" | Pennant

! scope="col" style="width:20%;" | Builder

! scope="col" data-sort-type="date" | Ordered

! scope="col" data-sort-type="date" | Laid down

! scope="col" data-sort-type="date" | Launched

! scope="col" data-sort-type="date" | Commissioned

! scope="col" data-sort-type="date" | Decommissioned

! scope="col" class="unsortable" | Fate

! scope="row" |

|Territory of Alaska

|CB-1

|rowspan=3|New York Shipbuilding Corporation, Camden

|rowspan=6|9 September 1940

|17 December 1941

|15 August 1943

|17 June 1944

|rowspan=2|17 February 1947

|Broken up at Newark, 1961

! scope="row" |

|Territory of Guam

|CB-2

|2 February 1942

|12 November 1943

|17 September 1944

|Broken up at Baltimore, 1961

! scope="row" |

|Territory of Hawaii

|CB-3<br>CBC-1

|20 December 1943

|3 November 1945

|colspan=2

|Broken up when 84% complete at Baltimore, 1960

! scope="row" | Philippines

|Commonwealth of the Philippines

|CB-4

|rowspan=3

|colspan=4 rowspan=3

|rowspan=3|Cancelled June 1943

! scope="row" | Puerto Rico

|Territory of Puerto Rico

|CB-5

! scope="row" | Samoa

|Territory of American Samoa

|CB-6

was commissioned on 17 June 1944. She served in the Pacific, screening aircraft carriers, providing shore bombardment at Okinawa, and going on raiding missions in the East China Sea. She was decommissioned on 17 February 1947 after less than three years of service and was scrapped in 1960.