Transport Submarine "Maru-Yu"
- Introduced Year : 1943
- Displacement : 230 ton
- Dimensions: 40.90 x 3.90 m
- Speed (max) : 7.5 knots on the surface, 3.5 knots in the water
- Engine : Hesselmann Engine 200PS x 2
- Armaments : Type 4 37mm Gun x 1, LMG x 5
- Loading Capacity : 20 tons
- Crew : 23 men
- Production Qty : 40
During the Pacific War, the IJA garrisons on the Pacific islands much suffered from the Allied blockage. IJN submarines were used for the supply to these islands. However, they could not supply them with even the least necessary quantity, because the transport was not a main duty for the IJN submarine. Therefore, the IJA decided to built special transport submarines and attempted the submerged transport by themselves.
Maru-Yu was developed by the IJA consulting with the IJN. Since it was made for the transport purpose, Maru-Yu has no torpedo. The structure of the Maru-Yu is simple and it has no watertight-partition in order to increase the capacity. It can dive to about 80m depth.
Maru-Yu was used for the transport to Leyte and islands near Japan proper.