These appear to have been Wilton-Fijenoord versions of the Bofors 15 cm Mark 6. Marks 9 and 11 were for twin mounts while the Mark 10 was for single mountings. All these guns used horizontal sliding breech-blocks and had similar ballistics. Surviving ships were supplied with British-built munitions during World War II.
Actual bore diameter was 14.91 cm (5.87").
| Designation | 15 cm/50 (5.9") Marks 9, 10 and 11 |
|---|---|
| Ship Class Used On | De Ruyter: Marks 9 and 10 Tromp: Mark 11 |
| Date Of Design | about 1935 |
| Date In Service | 1938 |
| Gun Weight | 7.38 tons (7.5 mt) |
| Gun Length oa | about 310.8 in (7.895 m) |
| Bore Length | about 293.5 in (7.455 m) |
| Rifling Length | N/A |
| Grooves | N/A |
| Lands | N/A |
| Twist | N/A |
| Chamber Volume | N/A |
| Rate Of Fire | 5 - 6 rounds per minute |
| Type | Separate |
|---|---|
| Projectile Types and Weights | AP: 103 lbs. (46.7 kg) HE: 101.4 lbs. (46.0 kg) British AP: 99.8 lbs. (45.3 kg) |
| Bursting Charge | N/A |
| Projectile Length | N/A |
| Propellant Charge | Dutch charges: 36.8 lbs. (16.7 kg) British charges: 35 lbs. (15.9 kg) Cartridge: 57.7 lbs. (26.2 kg) |
| Muzzle Velocity | AP: 2,953 fps (900 mps) |
| Working Pressure | N/A |
| Approximate Barrel Life | N/A |
| Ammunition stowage per gun | Tromp: about 330 rounds 1 Others: N/A |
- ^The ammunition stowage per is given in "Cruisers of World War Two" as being 2,000 rounds, but I suspect that this is an error, with this figure actually being the total ammunition outfit.
| Elevation | Distance |
|---|---|
| 29 degrees | 23,200 yards (21,214 m) |
| 45 degrees | about 30,000 yards (27,400 m) |
Data from:
- "Naval Weapons of World War Two" by John Campbell
- "Cruisers of World War Two" by M.J. Whitley
- Tony DiGiulian's personal data files
- 03 December 2008
- Benchmark
- 06 January 2009
- Added picture of De Ruyter firing