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 with almost intangible, 10,000 tons – eight 8 inches (203 mm). The British, the French and the Italians chose the configuration in double 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 pieces) on a strictly limited tonnage. Like other navies, we also choose the welding assembly technique to save tons of steel rivets.

Comparison between the Pensacola sister ships and USS New orleans at pearl Harbor October 1943.
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, rather than the contrary. In addition the tripod military masts were high and heavy, the aiming bridge, the conning tower. With a limited width and a slightly built hull, this caused a dangerous overweight in the heights and the Pensacolas were quickly deemed big “rollers”. Their lodging was so excessive that their rapid evolutions and turns were deliberately limited in operation. In addition their pitch was high due to a “flush deck” too short, narrow and overloaded at the front, which caused that these ships “nose down” and plough excessively and disturbingly, 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 keels in 1939 to improve their stability, then in 1942 their superstructures were lightened, while the massive tripod masts were 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 this new distinction in major pacific operations before being removed from active service in 1947. They were essentially repulsors that defined the next class, the Northampton. It must be said that the last class of “heavy” cruisers dated back to the armoured cruisers Saint Louis of 1908. This explains many theoretical deficiencies that led to the plans of these ships of a new and unprecedented kind in the US Navy.

USS Pensacola alongside USS Vestal after the battle of Tassafaronga, 17 December 1942
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 at the battle of Komandorski islands 26 march 1943

USS Salt lake City in action

(to come)

The end of Salt lake City as a target 25 may 1943
The end of Salt lake City as a target 25 may 1943

Characteristics (1941):
Displacement 9,100 t standard, 11,500 tonnes fully loaded
Dimensions: 178,5 x 19,9 x 5,9 m
Propulsion: 4 propellers, 4 Parsons turbines, 4 WF boilers, 107,000 hp. 32.5 knots.
Weaponry: 2×2, 2×3 x 203 mm (8 in), 4 x127 mm (5 in), 8 MG cal 0.5, 2×3 533 mm TTs, 4 seaplanes.
Protection: Turrets 165, belt 63, CT, casemate 105-50 mm, deck 51 mm.
Crew: 631 officers and sailors

USS Salt lake City 1932
The USS Salt Lake City in 1939. These over-armed sailors were so severely weighted in the highs that they were rebuilt in 1942.

USS Pensacola
The USS Pensacola in March 1945, in support of Okinawa. Note the evolutions with the original design

Sources
https://en.wikipedia.org/wiki/USS_Pensacola_(CA-24)
https://en.wikipedia.org/wiki/USS_Salt_Lake_City_(CA-25)