armored boat IJA landing support ship "AB" (Armored Boat) No.3

[aizenns 3,591]

AB艇 / 装甲艇三号艇

AB / Armored Boat (Soukoutei), No.3

• History of AB, Armored Boat

In 1920s, Imperial Army start to develop equipment for Landing Operations. As a result they develop lots of famous landing ships: Highspeed recon gunboat HB-K/ HB-O, Landing craft "Daihatsu", "Shohatsu", amphibious assault ship "Shinshu-Maru" etc.

But they know to need landing support ship with armor, machine gun and cannon: Soukoutei.

Soukoutei means Armored Boat, so sometimes IJA call this boat "AB艇": literary translation is "AB-boat".

 

In 1927 they built first prototype. That boat has perfect name, "Sakigake" (さきがけ): the pioneer. This boat has two 6.5mm machine gun and one 37mm gun, but it lack stability and 37mm is powerless.

Spoiler

Launched ceremony of "Sakigake" at Ujina port, Hiroshima pref.

This boat was used for patrol near Tianjin.

 

Next they build second prototype of Soukoutei, "Kachidoki" (勝鬨): the Battle cry. This boat expand its hull from 14.4m to 20m, displacement increased from 16 tons to 20 tons, and improved weapons. (1x 57mm and 2x twin 7.7mm)

Kachidoki was used for landing operation in January 28 Incident at Shanghai. This boat fire its gun to Chinese coastal positions and laying smoke to support landing boats. That battle was very successes. In that battle only 2 soldiers are died.

 

In 1932 IJA build Soukoutei No.3.

This boat modify its hull and new engine to increase its speed. And use lots of Electric welding to decease its mass.

It tested in 1933 and they decide start to mass-production based No.3.

This type of boat build 24 until 1937.

Spoiler

Soukoutei No.7.

Soukoutei were used for not only landing battle but fire support on river coast battles.

In 1937 production model changed. Soukoutei "model 1937" has hull length expanded from 16.5m to 17.5m for load troops or Munitions.

This model build 9 (No.27 ~ No.35)

 

Production model 1938 reduce hull length to 16.5 m but weapon was changed. Bow turret was removed and two 57mm turret placed on top of wheel room and engine room, and twin 7.7mm turret placed to side of wheel room.

Also it armor improved. Old models use Nickel-chrome armor but since 1938 Soukoutei use "Bullet-proof steel" as tanks.

Spoiler

Maybe Soukoutei model 1938

 

Production model 1939 has same hull of 1938 model but weapon changed.

Equip twin 7.7mm machine gun on bow turret and 57mm tank gun on turrets placed top of wheel room and engine room.

 

Last production model since 1940 boat shape is same as model 1938 but it turret can replace macinegun or tank gun.

 

Specifications of Soukoutei (AB) No.3

AB No.3
Between perpendiculars		Length		15.50 m
		Width		3.50 m
		Depth		1.65 m
Max		Length		16.000 m
		Width		4.000 m
		Depth		3.900 m
Draft (full load)		Bow		0.800 m
		Stern		1.20 m
		Average		1 m
Full-load displacement				20 t
Speed (light load)				27.8 km/h
Engine	Name			Nigata High-speed diesel
	Power			350 HP
Propeller				Spiral
Own wight				17.5 t
Troops				5-6
Weapon			Bow		1x 57mm Type 90 tank gun
			Top of steering room		1x Type 89, 7.7mm MG (twin)
			Top of rear engine room
			Rear		Smoke Discharger
Crew				5-6
Fuel consumption per hour				77.20 m3
Fuel tank				1265 m3 275 m3 (outside)
Armor			Over the water		4mm Nickel-Chrome steel
			Side of engine room		4mm + 3mm NCS
			Side of steering room
			Front of the turrets

 

Simple drawings of Soukoutei No.3~27

(銃 = machine gun, 砲 = Cannon)

 

Photo

• Body

Spoiler

• Exhaust / Smoke discharger

Spoiler

• TKG Turret

Spoiler

• MG Turrets

Spoiler

 

Flag of Army Ships

This boat is owned by Army, so this boat cannot use Rising Sun flag.

In this photo this boat use "Flag of Army ship"/ 陸軍附属船旗 and National Flag of Japan.

But in photos of Soukoutei at Chinese front, all Soukoutei have only National Flag of Japan.

 

Quote

 

Quote

 

Sources

Test of shipping support material (Soukoutei) JACAR Ref.C01004003200

Test of Soukoutei No.3

Specification and all Photo

 

Okumoto Gou (2016) "Boats and Ships of Japanese Army: For Landing, Transporting, Escort, Attack and special ships", Dai-Nippon Kaiga publishers

ISBN978-4-499-23177-0 C0076

History, drawings and clear scans of photo from JACAR ref.C01004003200

 

Fujita Masao (2008) "Unknown records of 'Army Shipping Units' " Maru, 61(4): 119-131

History

 

National Archives of Japan (Uploaded to JACAR)

Enact the Army vessel flag March 3, 1890

 

 

Edited November 21, 2018 by aizenns

[leroyonly 4,311]

Open for discussion. 

[BrentD15@psn 1,117]

Yes, please!

+1

[CoachJester 17]

yes +1

 

[aizenns 3,591]

Enact the Army vessel flag, March 3, 1890

Document from Ministry of the Army

 

I find original source of the flag by the Ministry of the Army! but this scan is monochrome...

• 三尺(3-shaku) ≒ 0.90909m
• 四尺貮寸(4-shaku 2-sun) ≒ 1.596m

官衙 means "Government office", and 名稱 means "Name". So this word in the flag means as "Write the office name here!" (In this time horizontal writing of Japanese language was written right to left)

But in the photos of Soukoutei or other blueprints of Army vessel, there aren't any word in the flag.

Edited November 5, 2018 by aizenns

[leroyonly 4,311]

As the Soukou-Tei No.3 will be coming in update 1.89,

 

Moved to Implemented Suggestions.