NAVYPEDIA



HOME
FIGHTING SHIPS OF THE WORLD
JAPAN
SUBMARINES
"Tei-Hyoteki D" "KORYU" midget submarines (HA77) (1945)


Photo



D type

Ships


Names Builders Commissioned Losses Transfers Discarding

波77 [HA77] and others, 570 boats at all (115 completed)

Ourazaki, Kure: HA77

Harima, Aioi: 39 boats

Hitachi, Mukazima: 30 boats (2 completed)

Kawasaki, Kobe: 47 boats

Kure K K: 100 boats (60 completed)

Maizuru K K: 50 boats (14 completed)

Mitsubishi, Kobe: 17 boats

Mitsubishi, Nagasaki: 69 boats (3 completed)

Mitsubishi, Yokohama: 32 boats

Mitsui, Tamano: 50 boats (30 completed)

Niigata, Niigata: 12 boats

Yokosuka K K: 50 boats (6 completed)

1/1945 - 7/1945

unknown

none

surrendered 8/1945 and BU: all survived


Technical data


Displacement standard, t 
Displacement normal, t

59.3

Length, m

26.3

Breadth, m2.04
Draught, m2.00
No of shafts

1

Machinery1 diesel-generator, 1 electric motor
Power, h. p.150 / 500
Max speed, kts

8 / 16

Fuel, t

4.5

Endurance, nm(kts)1000(8) / 125(2.5)
Armament

2 - 450 TT (bow, 2) or explosive charge (for "special" attacks)

Complement

5

Diving depth operational, m100


Standard scale images


<i>HA77</i> 1944
HA77 1944


Graphics


<i>D</i> type
D type


Ship project history


In December, 1943 on the basis of C type submarine designing of larger D or Koryu type has begun. The basic changes, in comparison with C type, consisted in fitting of more powerful diesel-generator for acceleration of process of battery recharging (its time was decreased to eight hours), raise of seaworthiness and improvement of conditions of habitability of the crew which has increased to five persons. Besides, the hull became notably more strongly, that has raised a diving depth to 100m.

In spring 1945, even before the end of lead boat trials, serial building had been developed. According to plans of Naval staff, by September, 1945 it was supposed to receive 570 submarines, with subsequent rate of building of 180 boats in a month. The section method (the boat shared on five sections), shranking the building period to 2 months, has been applied to acceleration of works. Despite attraction of the big number of builders to Koryu program, to maintain rate of delivery it was not possible and by August, 1945 only 115 boats were commissioned, 496 more were at various stages of building.

Modernizations


None.

Naval service


Fates are unknown.