Japan Once Built an Amphibious Tank, That Could be Launched from a Submarine

If there’s a place that could come up with otherworldly, out-of-the-box, never-done-before ideas, it would be no other than Japan. It was also showcased during World War II with the impressive naval capabilities it needed in order to efficiently fight off the scattered islands of the Pacific Theater of war. Although their tanks were not superior compared to those of the Allied forces, their innovativeness made it possible to bridge their tanks and naval capabilities through their amphibious tanks, which were no doubt impressive and the best of their kind.

Japan’s Amphibious Tanks

What could be better than an armored vehicle that could easily roll to the shore during an invasion in an island-y place? Virtually nothing! That’s why Japan started to work on the idea in the late 1920s and continued until World War II broke out. They started by creating a few experimental vehicles beginning from those that were 4 to 8 tons, like the SR I-Go, SR II Ro-Go, and SR III Ha-Go, and the Sumida Amphibious Armored Car prototypes.

When World War II broke out, Japan wanted to bring amphibious tanks with them on their upcoming Pacific campaign as they thought they would greatly help them break defenses in the remote areas. In the 1940s, they assigned the task of developing these vehicles to the Imperial Japanese Navy.

Using their knowledge and experience from the SR series of vehicles for their amphibious tank, they built their first amphibious tank using the chassis of Type 95 Ha-Go light tank. The Type 1 Mi-Sha, as it would be known, led directly into the Type 2 Ka-Mi. Both of them were based on the Type 95 Ha-Go. In 1942, Type 2 entered production with just over 180 of these tanks built until its production ended in 1943.

Type 2 Ka-Mi

As mentioned, the designers of Type 2 Ka-Mi decided to base its development on Type 95 Ha-Go, all while keeping its engine, transmission, suspension, drivetrain, and chassis. However, the hull and the turret were completely redrawn for the task. The tank’s crew and engine compartments were sealed with rubber gaskets and the armor plating was joined by the relatively new technology of welding rather than using rivets.  The inert gases used in welding were pretty expensive at the time, and the US did not adopt welding in the manufacture of military vehicles and ships until about 1938.

Captured Japanese Ka-Mi amphibious tank, tested by Americans in 1945. (Wikimedia Commons)Ka-Mi’s engine transmission was designed to power two shafts that could provide a 6-knot speed on the water, about 6.21 miles per hour, and a 93.2 miles maximal range. As for the steering, it was provided by a pair of rudders operated through cables that ran from the rear up to the driver’s compartment.

To avoid the top hull from being flooded, barriers were placed around the engine exhaust grid. There was also a removable chimney designed to be fitted over the exhaust pipe with a watertight seal. This was covered by a removable bell-like dome. Type 2 Ka-Mi had a 37 mm main gun and two 7.7 mm machine guns.

Japan’s conquests were over when the Type 2 arrived, but regardless, the Imperial Japanese Navy was happy with how it ended up and still wanted to push for further improvements.

Type 3 Ka-Chi

That improvement was the Type 3 Ka-Chi which went all the way as an ocean-going machine. Its armor was much thicker than the previous type and had a more powerful 47 mm gun. Type 3 was based on the Type 1 Chi-He medium tank.  By the standards of the time, it was one of the largest tracked vehicles produced by any nation in WWII at more than 30ft long.  The Porsche-designed King Tiger of Germany was 24ft long by comparison.

It still had the Type 2’s detachable pontoons, with the pair of rudders for steering placed in the rearmost pontoon. To improve streamlining, the sides of the hull were smooth and faired into the pontoons, while two screws at the rear provided propulsion underwater. Unlike Type 2, the pontoons were not needed for amphibious movements, and its two rear screws could be used as a basic steering system whenever the pontoons were removed.

A distinctive large snorkel was placed behind the turret to deliver air to the Mitsubishi engine and, at the same time, keep water out of the engine compartment.

The main armament of the Ka-Chi was the Type 1 46 mm tank gun that was used on the army’s Type 97 Chi-Ha Shinhoto and the Type 1 Chi-He. The secondary weapon was a coaxial Type 97 heavy tank machine gun, both of which were mounted in a modified version of the turret similar to the Chi-Ha Shinhoto.

A crew of seven was required to operate the vehicle, one of which was an onboard mechanic. A large conical cupola was built to make sure that the vehicle would not be flooded by waves breaking over the front of the vehicle.

The Type 3 could also be launched from the large cruiser submarines that the Japanese had built. These submarines had aircraft hangers aboard them that could launch three armed floatplanes.  The Type 3 had a convex plate riveted to its hull to withstand being crushed at depth and it would be attached to the deck.  The thought was that the sub could launch the Type 3 at night, have it crawl ashore and disgorge troops and supplies and then hide until darkness to return to the submarine. Lord knows how they planned to get back on deck again.

Production of Type 3 began in 1943, but only 19 were built because Japan’s priority at that time was building new ships and aircraft. None of these 19 tanks ever saw combat, and they were retained for the defense of the Japanese islands.