Pensacola class heavy cruisers (1928)
USA (1928-30) - USS Pensacola, Salt lake City
The top heavy cruisers
When the treaty of Washington was ratified by the great naval powers in 1922, the nomenclature of types was modified and, in a sense, concepts consecrated. Among these changes, the most notable was the appearance of a new class in its own right, the "Washington Cruiser" which in fact was the typical form of the heavy cruiser, a new category of Washington-compliant type cruiser, so 10,000 tons - eight 8 inches (203 mm). The British, the French and Italians chose the configuration in twin turrets. However the Americans from the beginning, confident in the design of triple turrets initiated for their dreadnought during the war, chose to adapt it for their cruisers, while maintaining a configuration in four turrets. The Admiralty had thus chosen a compromise with the most powerful artillery possible (ten guns) on a strictly limited tonnage. Like other navies, they also choose welding assembly techniques to save tons of steel rivets.
Comparison between the Pensacola sister ships and USS New orleans at pearl Harbor October 1943.
But these choices were paid later in practice and throughout their career. Indeed, triple turrets - the most powerful - were mounted in superfiring position due to size constraints fore and aft. In addition the tripod military masts were tall and heavy, the aiming bridge and conning tower all played a part on the ships being dangerously unstable. With a limited bream and a lightly built hull, this caused dangerous overweight in the heights and the Pensacolas
. Their list was so excessive when steering that rapid evolutions and hard turns were deliberately limited in operations. In addition their pitch and roll were high due to a short "flush deck" hull, narrow and overloaded forward, causing them a "nose down", plowing in heavy weather.
Refit blueprint of the Pensacola class 1941
Refit for service
In the end this Pensacola class appeared as quasi-experimental. Pensacola's sister-ship, USS Salt Lake City was launched in 1930 and completed in 1931. Both ships received additional counter-keels in 1939 to improve stability, then in 1942 their superstructures were curtailed and lightened, especially the massive tripod masts removed. They received a radar, new fire control systems, and a powerful AA artillery complement. This solved some of their deficiencies and they participated in major pacific operations before being removed from active service in 1947. They were essentially a first test of how not to do it, that defined the next class, the Northampton
. It must be said that the last class of "heavy" cruisers dated back to the Saint Louis
armoured cruisers class of 1908. This explains some theoretical deficiencies leading to these blueprints for an unprecedented type in the US Navy.
USS Pensacola alongside USS Vestal after the battle of Tassafaronga, 17 December 1942
Career of the USS Pensacola
(Work in Progress...)
USS salt Lake City at the battle of Komandorski islands 26 march 1943
USS Salt lake City in action
The end of Salt lake City as a target 25 may 1943
9,100 t standard, 11,500 tonnes fully loaded
178,5 x 19,9 x 5,9 m
4 propellers, 4 Parsons turbines, 4 WF boilers, 107,000 hp. 32.5 knots.
2x2, 2x3 x 203 mm (8 in), 4 x127 mm (5 in), 8 MG cal 0.5, 2x3 533 mm TTs, 4 seaplanes.
Turrets 165, belt 63, CT, casemate 105-50 mm, deck 51 mm.
631 officers and sailors
The USS Salt Lake City in 1939. These over-armed sailors were so severely weighted in the highs that they were rebuilt in 1942.
The USS Pensacola in March 1945, in support of Okinawa. Note the evolutions with the original design