The O 21 class submarine HNMS O 27.
Technical information
| Type | Submarine |
| Displacement | 990 / 1205 BRT |
| Length | 77.7 m |
| Complement | 39 men |
| Armament | 1 3.5" gun 2 40mm (2x1) 1 12.7mm MG 8 21" torpedo tubes (4 bow, 2 stern, 2 external amidships) 14 torpedoes |
| Max speed | 19.5 / 9 knots (surfaced/submerged) |
| Engines | Diesels / Electric, 2 shafts |
| Power | 5000 / 1000 HP (surfaced/submerged) |
| Notes on class |
|
1 submarine of the O 21 class lost. See all Submarine classes. |
Royal Dutch Navy (more on 