Number 13 - class battleship The " Number 13 " - class battleship was a planned class of four fast battleship s to be built for the Imperial Japanese Navy ( IJN ) during the 1920s . The ships never received any names , being known only as " Numbers 13 – 16 " . They were intended to reinforce Japan ' s " eight - eight fleet " of eight battleships and eight battlecruiser s after the United States announced a major naval construction program in 1919 . The " Number 13 " class was designed to be superior to all other existing battleships , planned or building . After the signing of the Washington Naval Treaty in 1922 , they were cancelled in November 1923 before construction could begin . Design and background . By 1918 , the Navy had gained approval for an " eight - six " fleet , all ships under eight years old . However , having four large battleships and four battlecruisers on order put an enormous financial strain on Japan , which was spending about a third of its national budget on the Navy . Despite this , the IJN gained approval of the " eight - eight - eight " plan in 1920 after American President Woodrow Wilson announced plans in 1919 to re - initiate the 1916 plan for ten additional battleships and six battlecruisers . The Japanese response required the construction of eight additional fast battleships in the " Kii " and the " Number 13 " classes . When designing the latter class , the Japanese followed the doctrine that they had used since the First Sino - Japanese War of 1894 – 95 of compensating for quantitative inferiority with qualitative superiority . In the words of naval historian Siegfried Breyer , " had [ the ships ] been completed , they would have been the world ' s largest and most powerful battleships . Their gun calibre alone would have caused a new and more intensive naval arms race . From an engineering aspect they were more than ten years ahead of their time because they anticipated the characteristics of the fully developed , fast battleship . " Naval architect s William Garzke and Robert Dulin concur saying , " These ships would have completely outclassed any European battleship " . The " Number 13 " class was designed by Captain Yuzuru Hiraga , the naval architect responsible for most of the previous Japanese capital ships . The ships were based on his previous " Kii " - class battleship and designs , enlarged to take guns . Description . The ships had a length of between perpendiculars and overall . They had a beam of and a draft of . The normal displacement of the battleships was . The class was intended to be equipped with four Gijutsu - Hombu geared steam turbines , each of which drove one propeller shaft . The turbines were designed to produce a total of , using steam provided by 22 Kampon oil - fired water - tube boilers , to reach a maximum speed of . The primary armament of the " Number 13 " class was eight 45 - caliber 457 - millimeter guns in four twin - gun turrets , two each fore and aft of the superstructure . No examples of this gun were ever built , but it was planned to fire a shell at a muzzle velocity of . The secondary battery consisted of 16 single 50 - caliber 14 - centimeter guns was mounted in casemate s in the superstructure . The manually operated guns had a maximum range of at an elevation of + 35° and fired at a rate up to 10 rounds per minute . The ships ' anti - aircraft defenses consisted of either four or eight single 45 - caliber 12 - centimeter 10th Year Type anti - aircraft gun s mounted around the single funnel . Each of these guns had a maximum elevation of + 75° and a maximum rate of fire of 10 – 11 rounds per minute . They could fire a projectile with a muzzle velocity of to a maximum height of . The " Number 13 " class was also designed with eight above - water torpedo tube s , four on each broadside . The waterline armor belt was intended have a maximum thickness of and , like the " Kii " class , it was angled 15° outwards at the top to increase its ability to resist penetration at short range . The deck armor would have had a total thickness of . Construction . After the end of World War I , the United Kingdom , the United States and the Empire of Japan all announced large capital ship building programs , incorporating design lessons from the war . These ships would have been much larger and more expensive than earlier vessels and President Warren G . Harding called a conference at Washington , D . C . in late 1921 to forestall a very expensive arms race . The attendees at the conference agreed to limit capital ship construction for the next decade and scrapped large numbers of existing ships as well as many ships still under construction . Japan suspended the " Number 13 " class while the conference was in progress before any ship was laid down and formally cancelled them on 19 November 1923 . As construction of the ships was scheduled to begin in 1922 , and completed by 1927 , they were already allocated to specific shipyards : " Number 13 " : Yokosuka Naval Arsenal ; Yokosuka " Number 14 " : Kure Naval Arsenal ; Kure " Number 15 " : Mitsubishi ; Nagasaki " Number 16 " : Kawasaki ; Kobe