page_title: Design B-65 cruiser
section_title: Design
hierarchical_section_title: Design B-65 cruiser / Design
caption_attribution_description: English: The Japanese battleship Yamato running full-power trials in Sukumo Bay, 30 October 1941.
context_page_description: Design B-65 was a class of Super Type A cruisers planned by the Imperial Japanese Navy before and during World War II. As envisioned by the IJN, the cruisers were to play a key role in the Night Battle Force portion of the "Decisive battle" strategy which Japan hoped, in the event of war, to employ against the United States Navy.
  Begun in 1939, plans were far enough along that tests were conducted with the main armament and against the underwater protection. Even though the ships were approved for construction under a 1942 fleet replenishment program, the prioritizing of aircraft carriers and smaller ships due to the war, followed by Japan's defeat, killed any chance of the B-65's construction.
context_section_description: Design work on the B-65s began in 1939.  Preliminary plans for the new class were finished by September 1940, and they were far enough along that tests of the lower protection—the armor intended to counter torpedoes and any shells that fell short but still hit the ship (albeit underwater)—and main armament were conducted from 1940 to 1941.
  These plans called for ships that bore a striking resemblance to the Yamato-class battleships, with the same "clipper bow, flush-deck construction, and a generally similar superstructure", albeit at a reduced size. Primary weapons were to be nine 310 mm (12.2 in)/50 caliber guns in three triple turrets. Secondary weapons included sixteen 100 mm (3.9 in)/65 caliber Type 98 dual-purpose guns in dual mounts on either side of the superstructure, twelve paired Type 95 25 mm (1 in) anti-aircraft guns, and four 13.2mm Hotchkiss machine guns. The weight of the main battery turrets was to be around 1,000 long tons (1,100 short tons; 1,000 t), with 350 long tons (390 short tons; 360 t) of that devoted to armor; however, no plans of how this latter figure was to have been distributed has survived.
  The cruisers were to be protected by 190 mm (7.5 in) belt armor sloped at 20° and 125 mm (4.9 in) deck armor. Four geared turbine sets would have generated about 42,500 shp each; for a total of about 167,674 shp, enough to power the ships through the water at 34 kn (39 mph; 63 km/h), faster than the "fundamental design requirement" of 33 kn (38 mph; 61 km/h).
  In an attempt to counter the Alaska-class cruisers' 305 mm (12.0 in) guns, a proposal to increase both the main battery to six 356 mm (14 in) and armor protection to resist against the same was put forth. However, the increase in displacement (to almost 40,000 long tons (45,000 short tons; 41,000 t)) and reduction in performance this entailed meant that nothing came of the proposed changes.
caption: Yamato on her trials in 1941. Had the Design B-65 ships been built, they would have borne a striking resemblance to this ship.
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