40 cm/45 Type 94 gun

Another official designation was 45 caliber Type 94 40 cm Gun. The gun was designed in accordance with the prevailing Japanese naval strategy of Kantai Kessen, the Decisive Battle Doctrine, which presupposed Japan would win a war by fighting and winning a single, decisive naval action. Essential to that victory was being able to out-gun and out-fight its adversary. No other ship built could match the firepower and broadside weight of a Yamato-class battleship. In spite of this, there were no battleship-to-battleship engagements involving either completed vessel of the Yamato-class. Musashi only fired type 3 AA shells out of her main guns before being sunk by air attacks. Yamato managed to engage enemy warships during the Battle off Samar, October 25, 1944, definitively confirming several hits with her 46 cm main guns to the escort carrier USS Gambier Bay and the destroyer USS Johnston, sinking both ships, alongside scoring a near miss to the escort carrier USS White Plains at 34,500 yards. Yamato also fired type 3 AA shells on several occasions, including during her final battle where she was sunk by carrier aircraft.

• Name — 46 cm/45 Type 94 • Origin — Japan • Type — Naval gun • Is Ranged — YES • Is Artillery — YES • Is Uk — YES • Design Date — 1934 • Service — 1940–1945 • Used By — Imperial Japanese Navy • Wars — World War II • Designer — C. Hada • Manufacturer — Kure Naval Arsenal • Number — ~27 • Weight — 147.3 tonnes • Part Length — 20.7 m, (45 calibres) • Cartridge — AP Type 91: 1,460 kg AP Type 1 1,460 kg? HE Type 0: 1,360 kg AA Type 3: 1,360 kg • Caliber — 46 cm • Rate — 1.5 - 2 rounds/min • Velocity — 780 m/s • Range — 25 km • Max Range — 42 km at 45° elevation • Breech — Welin breech block • Recoil — Hydraulic recoil mechanism • Carriage — Yamato-class battleship • Elevation — +45/-5 degrees. 10°/s • Traverse — 300°, 2°/s • Diameter — 46 cm

• Illustration — Kure naval arsenal's big lathe (N° 15299) Some 27 guns were built for the three battleships of the Yamato class. Only 18 were ever shipped, nine each aboard the and; the third vessel of the class, the, was converted into an aircraft carrier and sunk before it entered combat. The complex Type 94 barrels were constructed in three autofrettaged stages. A half-length tube was fitted over the first tube and shrunk onto it. The assembly was then wire wound and two additional tubes shrunk over the entire length of the gun tubes. A final inner tube was then inserted down the gun and expanded into place. This inner tube was then rifled to finish the gun. As designed, this gun could not cost effectively be relined but instead the entire gun tube would have to be replaced due to wear. All guns were crafted using the Kure naval arsenal's big lathe (N° 15299), which was specially made for this caliber. This machine is now displayed outside the Yamato Museum in Kure, Japan. • Illustration — Musashi firing her 46 cm guns on sea trials off the Iyonada Strait near Ōita, July 26, 1942 Unlike previous designs, when examined by a US naval technical team, the turrets were found to have nothing in common with previous British Vickers designs used in other Japanese battleships. Each gun was independently sleeved allowing for separate elevation. The shell hoists and powder rams were found to be ingenious though unduly heavy designs that allowed a relatively rapid rate of reload. 180 shells (60 rounds per gun) were stored in the turret's rotating structure. The shells were stored vertically, and an innovative system of geared mechanical conveyors was employed to move the extremely large and heavy shells from the shell rooms. The mechanical advantage required to move the heavy shells meant these conveyors operated extremely slowly but the 180 shells stored in each turret were considered sufficient for a surface engagement.

With Type 91 AP shell • Elevation — Range — Time of flight • 10° — 18410 yd — 26.05 sec • 20° — 30530 yd — 49.21 sec • 30° — 39180 yd — 70.27 sec • 40° — 44510 yd — 89.42 sec • 45° — 45960 yd — 98.6 sec

With Type 91 AP shell • Elevation — Range — Impact angle — Velocity • 2.4° — 5470 yd — 3.3° — 2264 ft/s • 5.4° — 10940 yd — 7.2° — 2034 ft/s • 8.6° — 16400 yd — 11.5° — 1844 ft/s • 12.6° — 21870 yd — 16.5° — 1709 ft/s • 17.2° — 27340 yd — 23° — 1608 ft/s • 23.2° — 32810 yd — 31.4° — 1558 ft/s • Illustration — A Type 1 armour-piercing shell at the Yasukuni Shrine in Tokyo. • Illustration — Drawing showing internal structure of Type 91 armour-piercing shell. • Illustration — High-explosive Type 0 shell. • Illustration — Yamatos 46 cm/45 Type 94 naval gun shells.

40 cm/45 Type 94 gun is classified as a naval artillery or rifled breech loader. Associated with Empire of Japan.