| Displacement | 893t surface, 1195t submerged |
|---|---|
| Length | 67.1m pp, 70.6m oa |
| Width | 7.2m |
| Draught | 3.9m |
| Machinery | 2-shaft diesel/electric motor, 2400bhp surface, 1600shp submerged |
| Fuel | oil 75t |
| Speed | 17kt surface, 8kt submerged |
| Range | 5500nm by 10kt surface, 80nm by 4kt submerged |
| Armament | 6-45cm TT, 1-8cm/28cal AA gun, 1-7.7mm MG |
| Complement | 48 |
| Name | Plan | Builder | Laid down | Launch | Complete | ||
|---|---|---|---|---|---|---|---|
| Ro-51 (SS-25) | FY1917 | Mitsubishi, Kobe | 1918. 8.10 | 1919.10.10 | 1920. 6.30 | SS2 (SS-25) | 1924.11. 1 renamed(Ro-51) 1940. 4. 1 disc |
| Ro-52 (SS-26) | FY1917 | Mitsubishi, Kobe | 1918. 8.10 | 1920. 3. 9 | 1920.11.30 | SS2 (SS-26) | 1924.11. 1 renamed(Ro-52) 1932. 4. 1 disc |