15 cm No 6, 7 & 8

These three guns are usually listed together as mounted together on two different classes of ships, the Java-class cruisers and the Flores-class sloops, both dating from the late twenties. The Mk.6 were Krupp guns obtained from Germany, originally built for a fortress. Eight were purchased directly from Krupp, the other twelve were built under license by Bofors in Sweden. The Mk.7 and Mk.8 were Krupp guns built under license by Bofors as well.

Java firing her starboard guns during a target practice

Gun specs
Manufacturer Krupp, Germany
Bofors, Sweden
Purpose Low Angle (seatargets only)
Bore 149,1 mm (5.9 inch)
Classes used on No 6:  Java class cruisers
No 7:  Flores-class sloops
No 8:  Johan Maurits van Nassau (I)
Length 50 calibers (actual length 7,895 m)
Dates in service No 6 & 7:  1925
No 8:  1933
Gunweight No 6 & 7:   7,24 tons
No 8:  7,33 tons
Initial velocity 900 metres per second
Shell specs
Shell weight 46 kg (HE)
Range (by WW 2) No 6 & 7:  16.700 metres *
No 8:  18.500 metres **
Mount specs
Elevation +25 / -10 degrees
Mount types Used behind armoured shields on all classes
Mount armour No 6: 100 mm (front) 25 mm (sides)
No 7:  14 - 80 mm
No 8:
Mount weight 21,720 tons
* Range of the guns of Java during the battle of the Java Sea. Flores and Soemba, with guns of Sumatra had a similar range
**: Maximum range of the guns of Johan Maurits van Nassau during her bombardment of a shore battery in May 1940

Sources
Jane's fighting ships of the World, 1931 edition
J. Anten et al "Hr.Ms. Kruisers 'Java' and 'Sumatra'

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