In the late 30's, the Japanese actively upgraded their cruisers by increasing the caliber of their main guns from 155 to 203 mm. By doing so, they secured a noticeable advantage over American New Orleans-class heavy cruisers and the heavy cruisers of the Baltimore class that were at the design stage.
To achieve decisive superiority over Japanese ships in terms of firepower, the Bureau of Ships presented a heavy cruiser sketch design codenamed CA-B. By increasing the number of main guns to 12, the Americans boosted the weight of fire with Mk19 and Mk21 shells to 1,414 kg and 1,519 kg, respectively, against the Japanese 1,258 kg.
«Spring Style» Drawing
Engineers presented three sketch designs for the new heavy cruiser designated CA-A, CA-B, and CA-C. Project СА-А featured nine main battery guns while the other two versions added three more. By speed, CA-A was one knot faster, offering a maximum speed of 34 knots. The design offered an innovative feature—the use of quadruple torpedo mounts, which had never appeared on the preceding cruiser classes before. Aircraft-handling equipment was placed amidships, echoing several design solutions implemented on New Orleans. This made space for four seaplanes, two stored on the catapults, ready for take-off, and two more parked in the hangar, one on each side.
The ships featured substantially reinforced armor that predetermined the use of a 190.5 mm armor belt placed on a 19 mm steel backplate. The 76.2 mm main armored deck was to withstand high-explosive drop bomb hits. The armor protection of the main guns was reinforced, too. Barbette armor: 196.85 mm; turret face: 229 mm, sides: 101-51 mm, roof: 51 mm; armored transverse bulkheads of the citadel: 190.5 mm. The main battery was to be composed of the battle-proven 203 mm Mk12 mod. 1 guns with a mounting scheme similar to that used on the Baltimore-class ships. Regarding dual-purpose artillery, the Americans stuck to their own standards, relying on 127 mm guns placed in Mk29 mod. 0 twin mounts.
The small caliber AA artillery was pretty weak at the design stage with four 28 mm Mk1 mounts placed on superstructures. Each mount had a place reserved for an Mk44 gun director, which by that time was already in use on ships, though on a limited scale. Quadruple torpedo mounts for Mk15 torpedoes were to be used. One of the key new features was a torpedo reload booster that was expected to even the odds when using torpedo armament in encounters with Japanese cruisers.
The technical design was based on the prototype of cruiser Wichita. During a review of the major weight loads and armor protection parameters, it turned out that the dimensions set by the design were impracticable—the ship would not be able to carry such powerful armament and armor without increasing water displacement. As a result, the trial configuration of displacement reached 18,042 tons, one ton in excess of the amount indicated in the performance specifications. The ship grew in length, reaching an LOA and LWL of 222.5 and 218.4 m, respectively. The beam and draft equaled 23.65 and 7.6 m, respectively. An extra—fourth—main battery turret required an additional section to be added to the ship, making the ship 7.9 m longer.
The main propulsion comprised a 120,000 hp plant with four shafts, four geared turbine plants produced by General Electric, and four Babcock & Wilcox boilers. The en-echelon arrangement of the engine and boiler rooms increased the endurance of the main propulsion. The projected speed was 33 knots in the 17,000-ton water displacement configuration. The operational distance equaled 12,000 miles at 15 knots. The ship's electric power plant comprised four turbine generators, 750 kW each, and two emergency diesel generators, 850 kW each, one fore and one aft.
Armor protection was reduced to save weight and meet the requirements for speed. During final calculations, the thickness of the armor belt was reduced to 127-152 mm, which was compensated by partially submerging the armor belt in the water. From the fore and aft sides, the magazine was protected by 152 mm transverse bulkheads. The propulsion plant was separated from the magazine with strong 127 mm extra transverse bulkheads to add more combat endurance to the ship in general. The barbettes of the main gun turrets were reduced to 152 mm, similar to the main battery mounts that were borrowed from Baltimore-class cruisers in an effort to harmonize the armament systems.
Estimates of the seakeeping characteristics demonstrated that with a propeller similar to that mounted on Baltimore-class ships and a trial water displacement of around 18,000 tons, the projected ship could sustain a speed of 32 knots. The ship's full load (combat) displacement reached 20,254 tons.
«Wartime» Upgrade of AA Defenses
With the outbreak of World War II, the nature of military operations at sea changed dramatically with aircraft carriers and carrier-borne aircraft playing a crucial role in deciding the outcome of battles. Had the Project CA-B cruiser actually been re-created in metal, the ship would inevitably have been subject to a modernization program that envisaged reinforcement of AA defenses. In that case, the ship's small caliber AA artillery would comprise 11 quadruple 40 mm Bofors Мk3 mounts; four twin 40 mm Bofors Мk1 mounts, and 16 twin 20 mm Oerlikon Мk20 mounts.
Calculations revealed that the ship's projected performance characteristics were way too optimistic. Even sketch-drafting for such a project might bring up difficulties related to the arrangement and the weight and size parameters of the main armament and armor protection, which can drastically affect both the overall performance characteristics of the projected ship and her architecture. This, in turn, could result in a complete revision of the project and the terms of reference in general.
Buffalo-class ships could well outmatch the Baltimore-class heavy cruisers in terms of their overall combat characteristics, but would cost more to build and service.
The project was not pursued, and with the outbreak of the war, military engineering science made a big leap forward after all naval arms limitations had been lifted. To secure superiority at sea, the development of Alaska-class cruisers carrying 305 mm main guns followed.