"Like the major European powers (and the US), the Japanese modified and adapted their basic tank designs to fulfill a variety of specialized roles. Unlike British and Americans, however, they were seldom able to produce these vehicles in sufficient quantities to be even noticed, much less effective in their secondary but often important tasks. One obvious example in the Pacific war was that of amphibious armored assault craft. The Japanese Navy did obtain a number of Ha-Go light tanks, and developed them into an amphibious tank, the Type 2 or "Ka-Mi." Two large detachable floats, shaped like the bow and stern of a boat, were fitted to the front and rear of a modified Ha-Go. The modifications consisted mainly (besides the hardware necessary to attach the floats, of course) of enabling the tank's transmission to drive a pair of screws when in boat mode, and also of steering wires which could be run into the tank itself allowing those inside to work the rudders on the stern float. The Ka-Mi had a top speed equivalent to about six miles per hour when in the water. The floats brought the vehicle's total weight to over 12 tons, and three additional men (besides the normal three-man tank crew on land) were assigned to the craft to help manage it when afloat, and also one imagines to give a hand installing and removing the floats. When striking the shore the Ka-Mi could drive right up on to the beach on its tracks, and it could even fight in amphibian mode, as the turret had full clearance and could be operated as soon as the rubber seals to make it watertight were removed. However, the encumberance of the heavy floats made the tank extremely awkward on dry land, and the intention was to remove them as soon as possible and then fight like a regular tank, in which case the vehicle reverted to being the basic Ha-Go in all important respects.
A problem with the Ka-Mi, first and foremost, was that the Navy wanted it as an amphibious assault craft for attacking defended beaches, but the vehicle only entered service in 1943, at a time when the Japanese were already largely on the defensive. Thus its usefulness was somewhat limited. Still, a few were encountered from time to time. Here is where memory gets a bit hazy, I can't find the source but think that perhaps the Japanese light tank that attacked the Marines on Betio in the Tarawa atoll (I seem to recall that two light tanks were discovered on the little island, but will stand correction in that particular as well) may well have been a Ka-Mi fighting without its floats. However, I'm not sure of that, it could have just been a regular Ha-Go in Navy service. Nevertheless, despite their seemingly more limited opportunities for employment– and of course the manufacturing difficulties, alluded to in previous instalments, of building such complex and specialized machines– the Japanese designed even bigger and more complicated amphibian tanks as the war progressed. The Type 3 or "Ka-Chi" followed hard on the heels of the Ka-Mi, appearing just as the latter was entering combat service. Based on the Chi-He medium tank, it had much more engineering for the aquatic side of its duties, including a large chimney-like air intake for rough seas. Few if any of these saw service, but as late as 1945 an even larger, purpose-built amphibian assault craft was being designed (with a Navy 25mm gun in its turret and a 57mm cannon in the front of the hull), although how anyone in the Japanese Navy could have imagined they would ever actually need such a vehicle at that stage of the war is frankly beyond me.
The Ka-Mi amphibious tank was introduced in 1942 (not 1943). The point to be made is that although they could build and deploy a handfull of these aquatic oddities, the Japanese could never produce the kind of amphibious armada the US forces were able to deploy by the middle of 1944, and which proved a major factor in the successful prosecution of their island-hopping campaign…"
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Amicalement
Armand
covers the basics for this WWII theater of war.
