These guns were all manufactured by Bofors and used by the Netherlands Navy on cruisers and sloops (gunboats) built during the 1920s. It is not clear what were the differences between these different Mark numbers, although I suspect that it had to do with the mountings. All of these guns used horizontal sliding breech-blocks and had similar ballistics. Surviving ships were supplied with British-built munitions during World War II. The sloops Flores and Soemba were intensively used during the invasions of Italy and had their worn-out guns replaced with ones removed from the cruiser Sumatra.
Actual bore diameter was 14.91 cm (5.87").
| Designation | 15 cm/50 (5.9") Marks 6, 7 and 8 |
|---|---|
| Ship Class Used On | Mark 6: Java class Mark 7: Flores class Mark 8: Johan Maurits van Nassau |
| Date Of Design | 1924 |
| Date In Service | 1925 |
| Gun Weight | 7.13 tons (7.24 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 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) Cartridge: 57.7 lbs. (26.2 kg) British charges: 35 lbs. (15.9 kg) |
| Muzzle Velocity | AP: 2,953 fps (900 mps) |
| Working Pressure | N/A |
| Approximate Barrel Life | N/A |
| Ammunition stowage per gun | N/A |
Data from:
- "Naval Weapons of World War Two" by John Campbell
- "Cruisers of World War Two" by M.J. Whitley
- "Warship Pictorial: The Royal Netherlands Navy 1945-86" article in "Warships Volume X"
- 03 December 2008
- Benchmark
- 16 June 2012
- Redid picture of RNN Java and added picture of Flores