Special Type 3 Motorboat "Ka-Chi" Amphibious Tank

[aizenns 3,591]

[Development] Summer marathon vehicles: Type 3 Ka-Chi

 

Japanese huge amphibious vehicle, Special Type 3 Motorboat "Ka-Chi" will comes in game! This vehicle was based upon Type 1 Medium Tank "Chi-He", but hull was completely rebuilded and have unique amphibious equipment to launch from submarines.

You can get this vehicle exchange of Five stars of the "Summer Landing" event.

 

 

Quote

History

The adoption of the Ka-Mi amphibious tank design opened up interesting opportunities for the General Staff of the Imperial Japanese Navy, when during a landing from the sea, it became possible to provide fire support with tanks that could go into battle immediately from the sea. The light Ka-Mi, however, did not provide the necessary firepower and did not have sufficient protection. In 1943, a new amphibious tank was created on the basis of the quite successful Chi-He medium tank, which received the designation Type 3 Ka-Chi. To transform into an amphibious tank, the Chi-He underwent a rather deep modernization: the armor plates were dismantled, the suspension was lengthened, equipped with two additional pairs of road wheels and rollers, a tall snorkel appeared over the cover of the engine compartment, and a distinctive dome appeared over the commander’s cupola. The Ka-Chi received front and rear pontoons, as well as a set of rubber plugs to seal the hull. The new amphibious tank successfully passed tests, however, by the beginning of mass production, the situation in the Pacific forced the naval authorities to concentrate all production capacity on the construction of new ships and carrier-based aircraft, therefore, by the end of the war, about two dozen Ka-Chi were produced, none of which were ever used in battle.

Is it a tank or a ship? The appearance of the Ka-Chi is very unusual - as if a patrol boat got out of the water and continued to move on land. Huge pontoons, a high air intake above the engine compartment and a protective casing with portholes over the turret, which looks more like a ship's bridge - all these make the Ka-Chi very much like a participant of War Thunder naval battles!

 

Unique points

As you see, structure of this vehicle is very unique: turret, side sponson, and suspensions are equipped on the pressure-resistance shell. Simply to say it was submergible tank to launch from submarine. (Maximum depth was about 100m !) 

In game, this design will works as spaced armor all around the hull. It will provide effective protection against HEAT shells which is popular in low ranks. Also, maximum armor is reaches 50 mm. Considering this armor and large floats, protection of this tank is good among amphibious vehicle.

 

Second unique point is its huge hull. Surprisingly, this vehicle is larger than the super-heavy tank, Pz.VIII Maus!!

This tank will be an idol of the battlefield.

	Maus	Ka-Chi (with float)
Length	10.085 m	10.3 m
Width	3.670 m	3.00 m
Height	3.630 m	3.82 m
Weight	187.998 t	28.5 t

 

[Vonarian 2,888]

3 minutes ago, aizenns said:

Surprisingly, this vehicle is larger than the super-heavy tank, Pz.VIII Maus!!

 

This is how an event vehicle should be 

[_qaz_ 675]

 

According to the devblog, "the average armor does not exceed 10-12 mm."

 

But isn't the armour of the frontal surface supposed to be 50 mm? I'm already concerned about the accuracy.

[Miki_Hoshii 2,449]

51 minutes ago, _qaz_ said:

 

According to the devblog, "the average armor does not exceed 10-12 mm."

 

But isn't the armour of the frontal surface supposed to be 50 mm? I'm already concerned about the accuracy.

I have no idea on the actual armor layout, but just by scale, i'd say only the mantlet has good proctection. I hope that if on land mobility is deemed acceptable by players, that we'll see an option for pontoons on the Ka-Mi as well.

 

 

Edited July 30, 2021 by Miki_Hoshii

[_qaz_ 675]

17 minutes ago, Miki_Hoshii said:

I have no idea on the actual armor layout, but just by scale, i'd say only the mantlet has good proctection. I hope that if on land mobility is deemed acceptable by players, that we'll see an option for pontoons on the Ka-Mi as well.

 

 

 

I measured this diagram's right side as a reference before posting that and got about 50 mm on the frontal surfaces, using the gun diameter. Of course it's rough and not exact.

But according to Tomio Hara's "Japanese Tanks" or Jiro Sayama's "Introduction to Armour" it should be 50mm at the front hull as well as the turret.

[コタリ 2,733]

I'm excited, but a little apprehensive. Like what has been pointed out with the armor. I find it hard to believe that the al most 29t Ka-Chi only maintains armor around the level of the half as heavy LVT-A1. Especially with the massive volume and specialty pontoons it should be relatively easy to fit heavier armor on while remaining neutrally buoyant. Hopefully overpressure doesn't absolutely screw this thing over where a small 200g HEAT shell hits the commanders tower optics and that causes the entire crew to just disintegrate.

 

I do hope this opens up the door to the Ka-Mi getting it's pontoons as well as them adding the Type 5 which would be a monster with it's 25mm autocannon as well as the 47mm. I do wish they would have shown us the special camo in the devblog. For some reason only the German ship got it's special camo revealed. I hope it's at least unique or reuse an interesting one such as the Ha-Go com, Ro-Go, or HT No.VI camo.

[qpranger 1,887]

"rebuilded" 

[コタリ 2,733]

Also I seriously hope they put the pintle mounted MG on this thing since with the pontoons on it will have no usable MGs.

[Wiggly_Armed_Man 2,383]

24 minutes ago, AnimeThighs said:

Also I seriously hope they put the pintle mounted MG on this thing since with the pontoons on it will have no usable MGs.

Don't worry comrade, you have rear turret MG.

[Fireraid233 4,274]

Some game info thanks to

@WT_CT_Center

Ka-Chi:

BR: 1.7

repair cost:

AB-2300

RB-1500

SB-1000

Edited July 31, 2021 by Fireraid233

[Fireraid233 4,274]

Also shouldn't it have at max 50mm of armor since it's a heavily modified Chi-he?

[tester188@psn 1,413]

When Type 3 Ka-Chi and Type 4 Ka-Tsu landing, the propellers can be drawn up, but in the dev blog, they seem to be fixed to the chassis. This reduces the possibility of the propellers getting caught in obstacles during landing. The Type 2 Ka-Mi did not have this feature.

Spoiler

 

Japan Administrative Division, 2nd Demobilization Bureau (April 25, 1947) "Japanese Naval Vessels at the End of War" . p. 202.

 

Ka-Chi Outline Drawing. Mitsubishi Heavy Industries, Ltd. Tokyo Machine Works

 

Ground Power, No.280, W.W.II Japanese Amphibious Tanks (グランドパワー, 日本軍水陸両用戦車). by GALILEO Publishing Co., Ltd. September 2017. Japanese magazine code: 13501-09. pp. 69, 75.

 

[Hisui_Soseki1218@psn 45]

The float on the front side should have a structure that can be divided into left and right, but it did not look like that on PV.

 

[_N4MELESS_ 2,972]

Although it has a modified Chi-He turret but you can still see in the model itself which has overlapped armor on the turret like the Chi-He so it is not possible that the protection doesn't exceed 10 mm. 

Spoiler

 

 

Edited July 31, 2021 by I_NAMELESS_I

[コタリ 2,733]

40 minutes ago, I_NAMELESS_I said:

it is not possible that the protection doesn't exceed 10 mm.

Remember. This is Gaijin we are talking about, where the Ji-Ro had worse armor than the Type 95.

[地球聯邦軍 25]

so, can this things swim in game?

[Fireraid233 4,274]

7 hours ago, EFAF said:

so, can this things swim in game?

Yes it should

[Pony51 6,572]

On 30/07/2021 at 20:52, tester188@psn said:

When Type 3 Ka-Chi and Type 4 Ka-Tsu landing, the propellers can be drawn up

HI Tester,

you have any information on the engine compartment?  Where the radiator and fan is?

[FloatingLAV 54]

The hull MG can still be used even when the pontoons are installed, and it can fire through the pontoons as well )))

[y_BNR32 73]

Bad news: They made the frontal armor of the car body 12mm thick. (Furthermore, side and back: 10mm) Also, there is no Water pressure resistant bulkhead. The body is literally a box made of 10-12 mm armor.
The armored model of this vehicle is very poor. I think we need to ask for a fix.

ネタバレ

I can take additional images if you need.

Edited August 2, 2021 by y_BNR32

[tester188@psn 1,413]

The Type 3 Ka-Chi has 50 mm of armor on the front, 16-20 mm on the sides, and 12 mm on the top. 

 

According to the books, the front armor of the hull is 50 mm and it also serves as a pressure hull to withstand 100 meters depth. It is made of NVNC or CNC steel, the RHA for warships provided by the Navy.

 

I will also investigate other issues with the model and share any sources that may be useful.

 

Quote

 

Type 3 Motor Boat

特三式内火艇

 

Armor

装甲

 

Front 50 mm, side 20-16 mm, top 12 mm

前面五〇粍　側面二〇〜一六粍　上面一二粍

Table of the Specifications of the Arms for Land Warfare. Research Department, Tateyama Naval Gunnery School.
https://www.jacar.archives.go.jp/das/meta-en/A03032103400

Edited August 2, 2021 by tester188@psn

[aizenns 3,591]

12 minutes ago, tester188@psn said:

The Type 3 Ka-Chi has 50 mm of armor on the front, 16-20 mm on the sides, and 12 mm on the top. 

 

According to the books, the front armor of the hull is 50 mm and it also serves as a pressure hull to withstand 100 meters depth. It is made of NVNC or CNC steel, the RHA for warships provided by the Navy.

 

I will also investigate other issues with the model and share any sources that may be useful.

 

Table of the Specifications of the Arms for Land Warfare. Research Department, Tateyama Naval Gunnery School.
https://www.jacar.archives.go.jp/das/meta-en/A03032103400

Those issues are already reported previously. Thank you to sharing the document!

[Pony51 6,572]

Anything that can be found about this beast is welcome, POST AWAY!

 

Meanwhile, we can have the Ka-Chi as a BOAT in game. 

This "tank" was designed as a seaworthy boat that could go on land.

Remember, even without the pontoons the tank is amphibious.  The pontoons are not really needed, unless you want to swim the 7 seas!

 

 

 

[tester188@psn 1,413]

Some miscellaneous sources.

 

I've already posted some of them, but this is the full page. The translation is not yet complete due to my lack of strength.

Spoiler

Front cover

カチ車要領図: Ka-Chi tank outline drawing

三菱重工業株式会社東京機器製作所: Mitsubishi Heavy Industries, Ltd. Tokyo Machine Works

(資料提供：大和ミュージアム): Source provided, Kure Maritime Museum/Yamato Museum

 

External view (top)

 

External view (front)

 

External view (rear)

 

Transmission layout and reduction ratio

 

Speed diagram

 

AC engine performance chart

 

Fuel and oil system

 

Auxiliary cooling system diagram, Oil water cooler and cooling water pump details

 

Power transmission device

 

Armament ammunition box layout

 

Pontoons detachable device

 

Propulsion unit, propeller (side)

 

 

Ground Power, No.280, W.W.II Japanese Amphibious Tanks (グランドパワー, 日本軍水陸両用戦車). by GALILEO Publishing Co., Ltd. September 2017. Japanese magazine code: 13501-09. pp. 55-69.

 

From a book by Lieutenant General Tomio Hara, who developed tanks for the Japanese Army. Translated the main specifications.

Spoiler

 

 

 

Specifications

• Weight (t) 
  • 26.450 (on the ground)
  • 28.750 (on the water)
• Crew: 7
• Dimensions (m)
  • Length: 10.300
  • Width: 3.000
  • Height: 3.824
  • Ground contact length: 5.020
  • Track width: 0.330
• Engine: Regulated model Type 100 Air-cooled V12 diesel
• Power: 240ps@2000rpm
• Armor (mm)
  • Turret: 50
  • Hull
    •  Front: 50
    •  Side: 20
    •  Rear: 20
    •  Top: 10
    •  Floor: 10
• Armament
  • 1 x 47 mm Type 1 tank gun
  • 2 x 7.7 mm Type 97 tank machine gun
• Ammunition
  • Main gun: 120 rounds
  • Machine gun: 5,000 rounds
• Performance
  • Maximum speed: 
    • 32 km/h
    • 10.5 km/h 
  • Max grade: 2/3
  • Max trench: 3.3 m
  • Cruising range
    • 320 km (on the ground)
    • 140 km (on the water)

Japanese Tanks and Fighting Vehicles. by Tomio Hara and Akira Takeuchi. 1961. pp. 99-101.

 

Type 3 Ka-Chi being tested on No.101-class landing ship. This seems to be an early production model without separated bow pontoons.

Spoiler

 

 

 

 

 

 

 

 

No. 149, 2nd class Transport Ship Ability Test (February to March, 1944)

Edited August 3, 2021 by tester188@psn

[aizenns 3,591]

6 hours ago, tester188@psn said:

Some miscellaneous sources.

 

I've already posted some of them, but this is the full page. The translation is not yet complete due to my lack of strength.

Thank you so much, these are extremely worthful documents!