gunboat IJA Daihatsu-class landing craft model D with 203mm rocket launcher

[aizenns 3,584]

20糎噴進砲装載大発動艇

Daihatsu with 20cm rocket cannon

 

About "Daihatsu"

Daihatsu is a shorten of Dai-Hatsudoutei (Large motor-Boat, LB).

Daihatsu model.D (LB-D) is the last model, and produced thousands.

 

This boat is only landing craft but there are very good specification, and some of them used for gunboat to support landing forces and defend landing crafts. For example, in the battle of Guadalcanal some boat equip 37mm or 75mm gun and machine gun to fight PT-boats. Surprisingly there ace-Daihatsu captain that destroy lots of PT-boats and called "Tiger of Solomon" (only self-name, so battle result is unknown: but some PT-boats destroyed by Daihatsu)

 

In the late of the war Japanese needs lots of small boats to attack landing forces on Japanese coast. Lots of Daihatsu equip guns and Torpedo, but its not enough, so they develop Daihatsu with 20cm rocket!

This boat have only one 20cm rocket launcher, but able to reload shells by Derick. (Bullet case is under gun)

 

Off coerce, this boat specification is very low. But I think this boat is very good toy as Katyusha!!

 

Specifications of the boat

Type of ship		Steel, Displacement type
Length		14.88 m
Max width		3.610 m
Depth		1.538 m
Own weight		10.7 t
Loads		8.5 t
Draft	Bow		0.470 m
	Stern		0.490 m
Speed	Full-load		7.5 kt
	Light-load		8.5 kt
Engine	60 hp diesel		1
	Propeller		1
Weapon	20cm rocket		1

 

Specifications of the Type 4, 20cm rocket launcher

Caliber		203 mm
Barrel length		1920 mm
Wall thickness		7.5 mm
Weight	Barrel (front)		31 kg
	Barrel (rear)		86 kg
	Cradle		20 kg
	Leg		44.5 kg
	Bottom plate		44.0 kg
	Total (include sight)		227.6 kg
Fire angle (vertical)		710 mil – 1160 mil
Fire angle (horizontal)		150 mil when vertical angle 800 mil

Spoiler

 

 

Specifications of Type 4, 20cm rocket shell "Ro-Dan"

Explosives	TNT 16.500 kg
Propellant (max)	9600 g
Fuse delay	0.0 or 0.1 seconds
Max speed	175 m/s
RPM	3000 rpm
Propulsion time	2 seconds
Max range	2500 m

 

Blueprints

Daihatsu mod.D

Spoiler

Daihatsu with 20cm Rocket

Spoiler

Blueprints of shell

Spoiler

 

Quote

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Photo of Type 4 20cm rocket launcher, displayed at Yasukuni Shrine, Tokyo.

Shell is replica.

from Wikipedia

Quote

Propeller of Daihatsu (This photo is mod.A late)

 

Quote

 

Sources

JACAR ref.C14010904500

技術戦訓報２０糎噴進砲装載大発動艇取扱要領書（案）／総説  (Manual of Daihatsu with 20cm rocket (draft) / review article)

 

JACAR ref.C14010904600

技術戦訓報２０糎噴進砲装載大発動艇取扱要領書（案）／附図 (Manual of Daihatsu with 20cm rocket (draft) / attached blueprints)

 

JACAR ref.C14020226400

線図 (Lines of Daihatsu model D)

 

JACAR ref. A03032106200

試製二十糎ろ弾説明書 (Instructions of Experimental 20cm Ro-Dan shell)

 

JACAR ref. A03032119600

一技研３研報第九号（◎砲１０１）試製四式二十糎噴進砲研究報告 (Research report of Experimental Type 4, 20cm rocket launcher)

 

Okumoto Gou (2016) "Boats and Ships of Japanese Army: For Landing, Transporting, Escort, Attack and special ships", Dai-Nippon Kaiga publishers,pp.9, 15

Photo of This boat, Blueprint of Daihatsu

 

Edited November 21, 2018 by aizenns

[leroyonly 4,223]

Open for discussion. 

[Miki_Hoshii 2,411]

Do you know how many rockets were carried?

[aizenns 3,584]

On 31/10/2018 at 08:45, Miki_Hoshii said:

Do you know how many rockets were carried?

Sorry, I can’t find that data. But in drawing it seems 8 or 12 bullets.

[onemax9000 1,236]

Oh yes now I can derp my way to victory  +1

[ShimakazeChan 2,389]

Naval Ho-Ro ))))))

[Fireraid233 4,099]

203mm rocket wow.

[Milocat 4,664]

Again, this boat would be very difficult to use, so I'm iffy on adding it, but it could be put in the game.

[CokeSpray 7,114]

Suggestion passed to the developers for consideration.