| Displacement | 1390t standard, 1500t surface, 2430t submerged |
|---|---|
| Length | 87.0m pp, 91.4m oa |
| Width | 8.8m |
| Draught | 4.60m |
| Machinery | 4-shafts diesel/electric motor, 5200bhp surface, 2000shp submerged |
| Speed | 20kt surface, 10kt submerged |
| Armament | 8-53cm TT, 1-12cm/45cal. gun, 1-8cm/40cal. gun |
| Complement | 60 |
| Name | Plan | Builder | Laid down | Launch | Complete | ||
|---|---|---|---|---|---|---|---|
| I-51 (SS-44) | FY1918 | Kure NYd | 1921. 4. 6 | 1921.11.29 | 1924. 6.20 | SS1 (SS-44) | 1924.11. 1 renamed as I-51 1940. 4. 1 disc 1941 sold |