Pensacola-class Cruiser

The ''Pensacola'' class was a class of United States Navy heavy cruiser, the first "treaty cruisers" designed under the limitations set by the Washington Naval Treaty, which limited cruisers to a maximum of displacement and a maximum main battery caliber of .

Development

Background

Initial efforts to design what would become the ''Pensacola''-class began in 1918 with the launch of the British ''Hawkins''-class cruisers. The US Navy believed the ''Hawkins''-class outclassed all American cruisers that were currently in service: an issue as Great Britain was considered a potential rival. Japan was also identified as a potential threat, and any war in the Pacific would have required uniquely designed ships that could cope with extreme range. To counter both potential adversaries, the new American cruisers needed to exceed the capabilities of the ''Hawkins''-class while possessing the range necessary to operate across the Pacific.

Washington Naval Treaty

In 1922, the United States and other naval powers signed the Washington Naval Treaty, intended to prevent a naval arms race and foster a sense of disarmament. The treaty limited future cruisers to displace less than 10,000 tons and armed with weapons with a caliber no greater than . The ''Pensacola''-class was the first American design built to treaty specifications, which allowed American naval architects to experiment with the requirements.

Description

In an effort to remain within treaty limits, while still mounting a very heavy main battery of ten guns, the hull was of welded construction, and the armor belt was thin (varying from in thickness). This was inadequate to protect her vitals from enemy 8-inch shells and was no thicker than the armor on gun cruisers. In fact, and were classified as light cruisers due to their minimal armor, until re-designated in July 1931 as heavy cruisers in accordance with the provisions of the London Naval Treaty to designate all cruisers with guns larger than 6.1-inch as heavy cruisers.

Their main armament consisted of ten 8-inch guns, in two twin turrets on the main deck, and two triple turrets two decks above, making it one of the two US Navy ship classes (besides the s) to have different-sized turrets for main armament. All the guns in each turret were mounted in a single slide, and were unable to elevate independently of one another. Also, unlike the very few other ships with different-sized main battery turrets (''Nevada''-class battleships and ''King George V''-class battleships) the ''Pensacolas'' had the larger turrets superfiring over the smaller turrets, whereas the others had the larger turrets on "bottom". Placing heavier turrets above lighter ones allows for finer lines for a given length, however causing top-heaviness and reducing stability.

Unfortunately, because of the rather unusual main battery layout and their heavy tripod fore-masts, they were top-heavy and prone to excessive rolling. This combined with low freeboard forward made them inferior seaboats compared to later designs. Rework in the shipyards modified the hull and superstructure in the 1930s to eliminate the rolling.

The Navy built only two ships in this class before switching to the design. Many of the deficiencies of the ''Pensacola''s were corrected by reducing the main battery to three triple turrets (two forward, one aft) and adding another upper deck forward of amidships.

Ships in class

See also

*County-class cruiser, a contemporary class of RN cruisers built to the same Treaty limits
* Furutaka-class cruiser, a contemporary class of IJN cruisers built to the same Treaty limits
*List of cruisers of the United States Navy

References

External links

Global Security.org – Pensacola-class cruiser

{{Treaty Cruisers
Cruiser classes