Special Type 3 Motorboat "Ka-Chi" Amphibious Tank

[Miki_Hoshii 2,449]

23 hours 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

 

Id presume that the upper side hull is 20mm and the lower side hull by the suspension and tracks is 16mm?

[Pony51 6,572]

I think this image is not a production unit, but an experimental version.

 

 

All the drawings posted and photos have no hint of a split forward pontoon.  This is the only image of this feature.

[Pony51 6,572]

On 02/08/2021 at 10:05, tester188@psn said:

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.

 

If indeed true, this "tank" (it is a BOAT SUBMARINE)  is comparable to dive depth of many submarines at that time!

 

That pressure hull must be very strong to withstand that pressure, practically be an armor itself.

 

The more I look at this, the more I believe it is an engineering masterpiece (just the propeller drive shaft is incredible complicated)

18 minutes ago, Miki_Hoshii said:

 

Id presume that the upper side hull is 20mm and the lower side hull by the suspension and tracks is 16mm?

The lower hull will be the same as rest of pressure hull.  

Think of this as a big cylinder with stuff welded on.

[GhostDivision5 45]

Hopefully the armor problem will be sorted out by the time people can get it on another note i hope they also fix the bug where the Ka-Chi shakes while moving when it has its floats equipped 

[tester188@psn 1,413]

If anyone can test the Type 3 Ka-Chi swimming ability, please check it out. The Type 2 Ka-Mi does not have a spinning propeller, it swims in a water jet like the PT-76, and has problems going backwards on the water. Gaijin accepted the source that the Type 2 Ka-Mi could swim without pontoons and fixed the problem, but gave it water jets instead of propellers.

[Pony51 6,572]

21 minutes ago, tester188@psn said:

If anyone can test the Type 3 Ka-Chi swimming ability, please check it out. The Type 2 Ka-Mi does not have a spinning propeller, it swims in a water jet like the PT-76, and has problems going backwards on the water. Gaijin accepted the source that the Type 2 Ka-Mi could swim without pontoons and fixed the problem, but gave it water jets instead of propellers.

Dev's are aware of issues, has not been fixed yet.

I think the 12th is soonest this unit will be in hands of players, have time to fix, a big pile of issues.

[GhostDivision5 45]

Looks like the gun elevation may be a bit too high in xray the gun clips into the turret ring

[GofereQ69843 64]

Armor changes :

https://github.com/gszabi99/War-Thunder-Datamine/commit/44f2184d42d300f80a3cca3172fde74cf0585a73#diff-a51bfe1c5bc3034ff85e8e565d9482aa6a1294686dd84864baf3de23d65a1bf0

[GhostDivision5 45]

 

@tester188@psn here you go btw the props are static like on the ka-mi

Edited August 3, 2021 by GhostDivision5

[GofereQ69843 64]

@GhostDivision5 it sinks if you don't move ?

Edited August 3, 2021 by GofereQ69843

[GhostDivision5 45]

it sinks when you reverse @GofereQ69843

 

[_qaz_ 675]

The side of the body is still only 10mm as I read?, while the minimum should be from 16 up to 20mm.

It's an important distinction for machine guns.

 

Also, is it possible to test drive this vehicle already normally?

[GhostDivision5 45]

the only way atm to test drive it is using this hanger https://live.warthunder.com/post/948290/en/ or create a cdk mission with it 

[_qaz_ 675]

 

Flotation is possible without the pontoons.

 

[_qaz_ 675]

I noticed a few bad aspects:

 

1. When pontoons are equipped, the chassis vibrates excessively while driving on land.

2. Without pontoons, reversing in the water works, slightly slower than forward. But with pontoons equipped, reversing causes the engine and crew to drown.

https://streamable.com/8djlvj

So at the moment, pontoons hinder your performance in water.

[Pony51 6,572]

On 02/08/2021 at 10:05, tester188@psn said:

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

Thank you very much for your effort!!

 

Is there any information on equipment list

Operation of the machine gun mount (pintel) on the snorkel?

And more drawings of the engine compartment?

 

What do you think is the diameter of the pressure hull?  The cylinder looks to be 2000mm in diameter.  Any other dimension information?

 

 

Meanwhile the Dev team IMHO is doing a GREAT job fixing the major issues!  More work needs to be done, but progress is going well!

Certainly one of the more challenging models they are doing.

 

There will be a lot of room to debate details, so every scrap of info is important.

[GhostDivision5 45]

just checked the Ka-Chi and it has been greatly improved since yesterday

• No longer shakes when moving with pontoons equipped
• is able to reverse in water without sinking
• pontoons now have collision
• armor has been updated
• x-ray has been updated
• cant use mg with pontoons on
• pressure hull has been added

[GhostDivision5 45]

also i just noticed that one of the wheels is missing the rust and dirt the other wheels have edit: checked all the other camos and its the same story

Edited August 4, 2021 by GhostDivision5
wording

[コタリ 2,733]

Btw is the reward camo available for viewing yet or no?

[Pony51 6,572]

1 hour ago, GhostDivision5 said:

just checked the Ka-Chi and it has been greatly improved since yesterday

• No longer shakes when moving with pontoons equipped
• is able to reverse in water without sinking
• pontoons now have collision
• armor has been updated
• x-ray has been updated
• cant use mg with pontoons on
• pressure hull has been added

Can confirm, as I posted earlier, great progress made.

 

A stumbling block is mounting the MG on snorkel pintle.  Need documentation on its use on Ka-Chi (and Ka-Mi).

51 minutes ago, GhostDivision5 said:

also i just noticed that one of the wheels is missing the rust and dirt the other wheels have edit: checked all the other camos and its the same story

Custom hangar?

[GhostDivision5 45]

@Pony51 yep https://live.warthunder.com/post/948290/en/  btw two I have 2 questions

1. is this article https://warthunder.com/en/news/7264-development-summer-marathon-vehicles-type-3-ka-chi-en going to be updated with the changes to the armor?
2. with the changes to the armor has there been any thought to increase its BR and Rank as with the armor increases the Ka-Chi feels more like a Rank 2 tank than a rank 1 tank

[Pony51 6,572]

6 minutes ago, GhostDivision5 said:

@Pony51 yep https://live.warthunder.com/post/948290/en/  btw two I have 2 questions

1. is this article https://warthunder.com/en/news/7264-development-summer-marathon-vehicles-type-3-ka-chi-en going to be updated with the changes to the armor?

Unlikely, and still not 100% finished.

6 minutes ago, GhostDivision5 said:

1. with the changes to the armor has there been any thought to increase its BR and Rank as with the armor increases the Ka-Chi feels more like a Rank 2 tank than a rank 1 tank

BR, unlikely.  Frontally is a tough nut, but sides are weak.  And it is a massive, easy to see and shoot target.  Will need to see how does in game, 1.7 seems like a good starter value.

Rank, lets petition for Rank 2.   Historically it was introduced in 1944.

[GhostDivision5 45]

At the very least i hope we can get it moved to rank 2 before players can get there hands on it.

[tester188@psn 1,413]

On 8/4/2021 at 1:09 PM, Pony51 said:

Is there any information on equipment list

Operation of the machine gun mount (pintel) on the snorkel?

And more drawings of the engine compartment?

 

What do you think is the diameter of the pressure hull?  The cylinder looks to be 2000mm in diameter.  Any other dimension information?

 

The Type 2 Ka-Mi's snorkel functions as a gun mount for a 7.7 mm machine gun, so the Type 3 Ka-Chi should have been the same.

Spoiler

 

The "snorkel" of the "Ka-Mi" has the unique feature of functioning as a "machine gun mount". By removing the hull machine gun "Type 97 tank machine gun" and re-installing it on the top gun mount of the "snorkel", the "snorkel" becomes a swivel gun mount capable of firing all around.

「カミ」の「通風筒」にはこれが無い代わりに「機関銃架」としての機能を備えている。ここに車体銃の「九七式車載重機関銃」を取り外し、この「通風筒」頂部銃架に改めて設置することにより全周囲発砲可能な旋回銃座となる。

 

Source: Book 

Good Weapons on the Losing Side, Volume 1, Completely Revised Edition. Written by Kogashuto. October 2020. ISBN-13: 978-4802209243. pp. 24-25.

 

Unfortunately, I don't have any more detailed source on the internal structure of the Ka-CHi. It is presumed that the Ka-Mi had a similar engine structure to the Type 95 Ha-Go light tank, so the Ka-CHi would be similar to the Type 1 Chi-He medium tank. Here's what's inside Ka-Mi.

Spoiler

MILITARY CLASSICS Vol.57. IKAROS Publications LTD. April 2017. Japanese magazine code: 18441-06. p. 32.

 

The diameter of the Ka-CHi's pressure hull is estimated to be 2 m. Some books explain the diameter as 3 m, but I think it is a misprint of 2 m because the width of Ka-CHi's hull is 2900 mm. I measured it from the blueprints and it was almost 2000 mm.

Spoiler

 

 

The engine is housed in a cylindrical, pressure hull with a diameter of 3 m. (translator's note: 2 m?)

エンジンは直径3mの円筒形の耐圧船殻に収められており

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. 30, 66.

[Pony51 6,572]

13 minutes ago, tester188@psn said:

Unfortunately, I don't have any more detailed source on the internal structure of the Ka-CHi. It is presumed that the Ka-Mi had a similar engine structure to the Type 95 Ha-Go light tank, so the Ka-CHi would be similar to the Type 1 Chi-He medium tank. Here's what's inside Ka-Mi.

Arigatou!

Not ideal, still useful.

 

The Ka-Mi might have been based on Ha-Go, but I doubt the Ka-Chi is based on any tank.  I think it is based on a submarine.