Several years before the Type2 Ka-Mi was introduced, Japan experimented with a number of amphibious tank designs. The most successful of those designs was the Ishikawajima Automotive Works SR-II “Ro-Go.” While it was not selected for mass-production, it does offer a solid machine gun-only starting vehicle for an amphibious development tree for Imperial Japan in Games.
In late 1934 Ishikawajima was charged by the Army with development of a new amphibious tank. This follows on only a year after they had made an amphibious version of the Type92 Heavy Armored Vehicle that tested well but was not selected for production. Weight for the new armored car was set at 7 tons with two machine guns and a maximum armor of 10mm after Mitsubishi had tried their own much lighter amphibious armored vehicle (the SR I-Go) carrying one machine gun – and did not impress the Army with it despite some interesting innovations including propulsion entirely through movement of the tank’s tracks (no propeller).
The Ishikawajima SR-II prototype was finished in mid 1935. It had a completely new Horstmann-type suspension consisting of three roadwheels, one return roller, a frontal driving sprocket and a rear idle wheel. The two forward roadwheels were connected by a small coil spring and a bogie. The rear roadwheel was connected the same way with the idle wheel. The bow was an integrated boat-shaped one that increased acceleration while afloat. An armor plate integrated in the middle of the bow armor could be raised as a splash shield.
On the bow and each side several flotation chambers were mounted. These were designed flatter to lower the silhouette. The driver had a rectangular cupola with visor ports on the front and right side. He entered the vehicle through a large rectangular hatch above his position. On his left side the bow gunner was placed below a slightly larger rectangular cupola. A cap on his hatch increased his firing angle. He operated a Type91 6.5 mm tank machine gun in a standard mount. A closable visor port was placed to the left of the gunner.
The turret had an octagonal basic shape with sloped sides. A standard MG mount for a Type91 6.5 mm tank machine gun like the one in the bow was mounted in the frontal plate. Closable visor ports were placed in each forward side and side armor plate and in the rear. The commander/gunner entered the tank through a large access hatch with a big cap. A grid construction behind the turret simplified access to the vehicle afloat.
The engine was placed lengthwise in the rear. Exhaust pipes lead from the rear to a muffler and raised tail pipes behind the turret on each side. Two 500mm propellers with rudders were attached to the rear.
The vehicle was designated “SR Ro-Go ” Amphibious Tank Version 2, short designation SR-II. During initial tests the vehicle showed a good mobility on land and afloat. A small pre-production series was finished until late 1935. Total production unknown, but greater than 2.
Operational tests were successful but the armament was still rated too weak — ironic since the Type92 Heavy Armored Vehicle accepted only two years prior by the Cavalry branch of the Army had the same armament (though it was later upgraded). Nevertheless the concept was overall rated “good.” For purposes of “what if” scenarios it is worth considering whether or not the vehicle would have been accepted by the Army if it had employed the 13.2mm Type92 heavy machine-gun that was used in the upgraded Type92 Heavy Armored Vehicle.
The fate of the vehicles is unknown. At least one was captured in 1945 by Soviet units in Manchuria. There is no known survivor.
vehicles built: >2
weight: 6.9 (metric) t
crew: 3 men
length: 4100 mm
width: 1800 mm
height: 1600 mm
engine: gasoline engine
armament: 2 X Type91 6.5 mm Tank MG
The SR-II Ro-Go is an amphibious equivalent of the Type92 Heavy Armored Vehicle or one of Japan’s armored cars, and could be introduced in limited numbers (around 4 max to stay close to history) to games as an early predecessor to the Ka-Mi. This could be especially useful in game scenarios meant to be recycled for multiple years/eras, where there is still space for amphibious landings / tanks prior to 1942 (when the Type2 Ka-Mi was introduced). It could also be used in an early war invasion map, such as Burma or Malaya, joining landing Army troops.
Fan created mod for Command and Conquer’s “Yuri’s Revenge” that includes the Ro-Go