These guns were manufactured by Bofors, Hollandsche Industrie-en Handelsmaatschappij (HIH) and Krupp and used by the Netherlands Navy on cruisers and sloops (gunboats) built during the 1920s. All of these guns used horizontal sliding breech-blocks and had similar ballistics. Surviving ships were supplied with British munitions during World War II. The sloops Flores and Soemba were extensively 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") for all guns.
| Designation | 15 cm/50 (5.9") Marks 6, 7 and 8 1 |
|---|---|
| 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 | (6.073 m) |
| Grooves | (48) 0.059D x 0.219W in (1.5 x 5.55 mm) |
| Lands | 0.165 in (4.20 mm) |
| Twist | RH 1 in 30 |
| Chamber Volume | N/A |
| Rate Of Fire | 7-8 rounds per minute |
- ^Eight Mark 6 guns were produced by Krupp while twelve guns were made by Bofors. Mark 7 guns were all made by Bofors. Mark 8 guns were produced by HIH.
| Type | Separate |
|---|---|
| Projectile Types and Weights | AP - 103 lbs. (46.7 kg)
Mark 6 guns: HE L/4,1 No. 1 - 101.4 lbs. (46.0 kg) Mark 7 and 8 guns: HE L/4,1 No. 2 - 102.0 lbs. (46.25 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 |
| Elevation | Distance |
|---|---|
| 29 degrees | 23,200 yards (21,214 m) |
| Designation | Single, open-back mounts
Java (10) and Sloops (3) |
|---|---|
| Weight | 20.0 tons (20.35 mt) |
| Elevation | Mark 6 guns: -10 / +25 degrees
Mark 7 and 8 guns: -10 / +29 degrees |
| Elevation Rate | N/A |
| Train | about +150 / -150 degrees |
| Train Rate | N/A |
| Gun recoil | N/A |
"Dutch Naval Weapons of the early 20th Century" by Stefan Boon (unpublished manuscript)
"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"
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Collection of Netherlands Institute for Military History (NIMH) Photographs (Dutch Language)
03 December 2008 - Benchmark
16 June 2012 - Redid photograph of RNN Java and added picture of Flores
21 March 2023 - Converted to HTML 5, added details to gun, ammunition and mountings