japanese amphibious afv

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#1

Hi.

A less known side of the japanese armed forces is the development and use of even high-sea-suited armoured vehicles. Almost all armies of WW2 had amphibious afv but only the japanese models could be used for oceanic operations.

This article will be divided in four parts due to the picture limitation.

  1. early prototypes:

In 1930 the japanese army started the development of an amphibious halftrack based on the french Kegresse suspension. It should serve as armoured recon vehicle especially for the cavalry-units.

The development was made by Ishikawajima. The vehicle was built with a boat-like hull. It had to be steered via the two roadwheels in the rear and by screws next to this wheels while afloat.

The vehicle was named AMP for “amphibious”. The abilities afloat were higher than expected.

On the other hand the vehicle showed some larger problems regarding the engine and the cross-country abilities and so the development was stopped.

In early 1932 the type 92 heavily armmoured vehicle was introduced. Immediately Ishikawajima developed an amphibious version also.

This vehicle was only built in small numbers and used in few maneuvers only.

To be continued

Yours

tom! :wink:

#2

Hi.

  1. The SR-prototypes.

In 1933 Mitsubishi was ordered to develop a light amphibious tank for Army recon units. The vehicle was based on the suspension of the type 92 light armoured vehicle. Multichambered floats were installed above the susopension and in the rear giving the vehicle a box shape. It was named experimental amphibious tank SR-I (Suiriku-Ryoyo I-Go= amphibious, version 1)

The tank was propelled by the tracks´ paddling effect giving a maximum speed of 9 kph afloat. A small rudder below the rear was used for steering. With a crew of 2 men the tank had a small driver´s cupola and a conical turret equipped with a type 91 6,5 mm tank mg. the weight was 3,7 t and the maximum speed 24 kph.

One prototype was built and tested. Due to the poor abilities afloat (non-effective steering, propulsion problems) and the weak armament the project was abandoned in 1934.

In late 1934 Ishikawajima was ordered to remodel the SR-I to increase the abilities afloat. The project was named SR-II (amphibious, version 2).

The floats were made lower and the upper superstructure was designed slightly sloped. The hull was rebuilt and made boat-like. A second type 91 6,5 mm mg and a gunner were placed on the left besides the driver. The suspension was totally reworked using a lot of construction elements of the type 95 light tank Ha-Go. The maximum armour was 10 mm, the total weight 7t. A smal zero-production was made and the vehicles were tested immediately. At least one vehicle was captured by russian troops in Manshuria 1945.

Due to the poor armament the project was abandoned in 1935.

In late 1935 Mitsubishi was ordered to rework the SR-II with an increased armament and a modified version of the steering of the Mitsubishi-made type 95 light tank Ha-Go. This project was named SR-III (amphibious, version 3).

The floats were slightly enlarged by increasing the width. The steering was upgraded with parts of the steering of the Ha-Go increasing the cross-country abilties. The use of welding in some parts decreased the weight of the armour. The turret was enlarged but due to a weight limitation of 7,5 t even the turret of the Ha-Go was tooo heavy. So a smaller version armed with a type 93 13,2 heavy tank maschine gun was designed. With the weight limitation Mitsubishi saw no chance to install a larger (and heavier) gun. The Army refused to increase the weight limit.

With the problems regarding armament/weight the japanese Army instead decided to abandon the project of an amphibious tank and handed over all project data to the Navy. There were no further Army projects.

To be continued.

Yours

tom! :wink:

#3

Hi.

  1. The type 2 amphibious tank Ka-Mi

In the late thirties the japanese Navy decided to develop amphibious tanks for the Special Naval Langing Forces. Basic recommendations were the use of a type 98 37 mm tank gun and the tanks should reach the beaches departing directly from the transport vessels ashore or from nearby islands. So the tanks had to be somewhat seaworthy.

Based on the SR-III-design Mitsubishi built a new vehicle with a simplified superstructure and the suspension of the type 95 light tank Ha-Go. The floats were removed increasing the size of the fighting compartment. A front and a rear pontoon were installed. All three part together (rear pontoon, tank and front pontoon) were building a stable boat-shaped sea-going vehicle retaining stabillity even in in a rolling sea.

The pontoons could easily be removed by simly pulling two wires operating quick-release locks. The pontoons could be refitted in 15 minutes.

The large frontal pontoon consisted of two symetrical sections with 3 compartments each. This ensured flotability even if the pontoon was hit. The capacity was 6,2 m³. The pontoon could be broken along the center line to allow the tank to move on if the landing zone didn´t allow to maneuver.

The rear pontoon consisted of 5 compartments with a total capacity of 2,9m³. The tank was propelled afloat by two 500 mm propellers below the rear pontoon and steered by a single rudder between the propellers.

For the use in heavier sea a chimney-style extension could be installed above the engine air intakes and a conical turret extension for better sight

The first prototype showed some problems which were solved quickly and in 1941 the serial production started. Major problems regarding the steering were solved in 1942 and from late 1942 an improved version with two steering rudders, improved armour and radio equipment was produced.

The weight was 13,2/8t with an armour strength between 6 and 16 mm.

The crew of five men consisted of driver, bow gunner, mechanic, loader and commander/gunner/skipper. The armament consisted of a type 97 7,7 mm tank maschine gun on the left in the bow and a type 98, later type 1 37 mm tank gun in the slightly conical turret.

As the pontoons extension formed a large overhang the target beaches had to be gently sloping and wide.

The Tanks were used in tank companies attached to the SNLF-bases. The tank doctrine was similar to the one used by the Army (infantry support and fast armoured recon). The tanks were used on Saipan, New Ireland, Rabaul and the Philippines. In October 1944 the 101st SNLF started an amphibious assault on Leyte causing much trouble among the US troops after landing behind the enemy lines.

To be continued

Yours

tom! :wink:

#4

Hi.

  1. WW2 amphibious afv-projects.

In 1943 Mitsubishi was ordered to remodel the type 1 medium tank Chi-He as an amphibious tank similar to the Type 2 amphibious tank Ka-Mi. The suspension of the type 1 Chi-He was enlarged by two roadwheels to cope with the higher weight (28,2 t with pontoons) and the higher forces caused by the increased length.

The pontoon system was an enlarged copy of the system used with the type 2 Ka-Mi. The crew of 6 men consisted of driver, bow gunner, mechanic/wireless operator, loader, gunner and Commander/skipper. The turret of the type 1 Chi-He was armed with a type 1 47 mm tank gun and a type 97 7,7 mm tank maschine gun in the turret rear. The vehicle was named type 3 amphibious tank Ka-Chi.

Some 20 were built from early 1944. Few were used by the 101st SNLF during the assault on Leyte in October 1944.

In 1943 Mitsubishi also started a project for an armoured amphibious multi-purpose vehicle based on an enlarged suspension of the type 95 light tank Ha-Go with integrated non-releasable floats. The boat-like hull and the superstructure were totally watertight. Two lowerable propellers gave the vehicle a speed of 11 kph afloat. The suspensuion consisted of 8 roadwheels and 4 return rollers. A command cupola was installed on the first third of the vehicle, toped by an semi-open helmsman station.

The vehicle could carry up to 8 soldiers ashore. It could also be used as armoured transport, small attack vessel equipped with two Long Lance torpedoes or air defence vehicle with two type 96 25 mm aa-guns in single mounts. For secret operations the vehicle could be carried by submarines similar to the Kaiten-minisubs. Due to the watertight construction the vehicles could have been released below the surface.

The vehicle was named Type 4 amphibious transport Ka-Tsu. Some 100 were built in 1944/45 and mainly used as supply vehicles for cut-off islands transported by subs.

In 1945 an amphibious tank project based on the type 4 Chi-To tank prototype was started with the project designation Type 5 amphibious tank To-Ku. Only early studies were made until surrender. The planned armament was a type 1 47 mm tank gun in the bow, a type 96 25 mm maschine cannon in the turret and a type 97 7,7 mm tank mg in the turret rear.

Thats it.

Yours

tom!

#5

These are some great pics Tom.

#6

Hi Tom
This is captured in 1945 Ka-Mi-SIA in Kubinka museum

#7

i believe that the first ever amphibious car or WW2 craft was designed by my great uncle, i know that he was the lead designer who developed the duck boats in boston but i bet not many people here know what they are…

#8

3D model:
Type 4 “Ka-Tsu” - amphibious carrier. Japan, 1944

This weird desig even carried two torpedos ¡¡ :shock:

#9

Hi.

There´s a little error in the 3D-pic. The type 4 Ka-Tsu carried two torpedoes or two aa-maschine cannons. There was not enough room to operate both weapon systems

Yours

tom! :wink:

#10

Just goes to show the Japanese truly were absolutely barking. What possessed them to think torpedoes on a tank were a good idea?

#11

Hi.

Don´t forget that this afv was a Navy project.

The type 4 Ka-Tsu had a low silouette afloat and during a night operation the vehicle may sneak to the enemy landing force, fire the torpedoes and sneak away. It´s a suicide mission anyway but the japanese did so with aircraft so why not using these vehicles?

I´m not sure if the US shipbourne surface radar would have been able to detect these relatively small vehicles.

In reality these vehicles were urgently needed to supply cut-off islands. So the japanese Navy never planned any attack operations.

Some detail views:

Yours

tom! :wink:

#12

Hi.

Some line drawings:

Type 3 Ka-Chi:


Type 4 Ka-Tsu:

Yours

tom!

#13

thanks for the pics. Are there any condensed stats for the vehicles such as weight, crew, weapons, speed, and Numbers built

#14

The DUKW? There’s one of them at the bottomw of my parent’s road (or at least there was when I was a kid, I’ve not gone down there since I was about 15). The guy who owns it used to use it to take people on trips up and down the Mersey I believe. Next time I’m on leave I’ll get some photos if it’s still there.

#15

Hi.

Informations especially on the pre-war prototypes are rare as most research results were destroyed just before surrender. I found these stats:

No data for type 92 heavy armoured car, amphibious version.

amphibious halftrack AMP:

manufacturer: Ishikawajima Jidosha Seisakusho
vehicles built: 1
weight: 2,5 t
crew: 2 men
maximum armour strength : 5 mm
length: 4000 mm
width: 1600 mm
height: 1900 mm
engine: Ford type A 4-cylinder gasoline
power: 40 PS
maximum speed: 45 km/h
maximum speed afloat: 9 km/h
power-weight-ratio: 16 PS/t
armament: 1 X type 3 6,5 mm HMG

experimental amphibious tanks SR-I / SR-II / SR-III

manufacturer: Mitsubishi K. K. / Ishikawajima Jidosha Seisakusho / Mitsubishi K.K.
vehicles built: 1 / 2 + ? / 1 + ?
weight: 3,6 t / 7 t / 7,5 t
crew: 2 men / 3 men / 3 men
length: 4970 mm / 4140 mm / 4100 mm
width: 2360 mm / 1860 mm / 1960 mm
height: 2100 mm / 2160 mm / 2140 mm
width of tracks: 245 mm / 195 mm / 195 mm
engine: 4-cylinder Diesel / ? / ?
power: 70 hp / ? / ?
maximum speed: 24 km/h / ? / ?
speed afloat : 9 km/h / ? / ?
armament turret: 1 X type 91 6,5 mm MG / 1 X type 91 6,5 mm MG / 1 X type 93 13,2 mm HMG
armament bow: - / 1 X type 91 6,5 mm MG / 1 X type 91 6,5 mm MG

Data for the other vehicles can be found at takis website.

Yours

tom! :wink:

#16

I don’t know but the 3dcg from gunpoint-3d’s cammo did’nt quite look japanese.

#17

Hi.

The standard tank camo of the japanese navy was grey, during the Philippines operations in 1944/45 dark green.

Yours

tom! :wink: