Description

These Bofors guns were to be used in the Netherlands Eendracht class cruisers, but the outbreak of World War II stopped work on those ships. Delays in shipbuilding caused by the war allowed Bofors to design and develop an automatic shell handling system which included dual ammunition hoists (AA and AP). Eventually, these weapons wound up on the Swedish Tre Kronor (Three Crowns) class cruisers. Later still, new guns were produced to arm cruisers for the Netherlands. The turret designs for both nations were also by Bofors and had high maximum elevations to allow these guns to operate in the AAA mode. In the postwar designs, the bore diameter was apparently increased to allow the use of Swedish 6" (15.2 cm) shells.

The Swedish ammunition for these guns is unusual in that the projectiles and cartridge cases are stowed separately but are rammed together on a cartridge carrier to become a fixed round before hoisting into the gun. This design has been criticized by British observers on the grounds that it requires very tight tolerances on all cartridges and mechanisms involved and is an obvious source of problems should this not be the case. Given the problems experienced by the British and United States with their automatic 6 inch (15.2 cm) guns of the same period, it would be interesting to know if Bofors had similar problems.

The data that follows is, wherever possible, for both nation's ships.

Gun Characteristics

Designation Eendracht: 15 cm/53 (5.9")
Tre Kronor and de Ruyter: 15.2 cm/53 (6") Model 1942
Ship Class Used On Netherlands: Eendracht Class (not built) and de Ruyter
Sweden: Tre Kronor Class
Date Of Design Netherlands: 1939
Sweden: 1942
Date In Service 1947
Gun Weight N/A
Gun Length N/A
Bore Length about 318 in (8.072 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire Eendracht Class: about 6 rounds per minute
Tre Kronor and de Ruyter: 10 (AP) or 15 (AA) per minute

Ammunition

Type Separate
Projectile Types and Weights HE: 101 lbs. (45.8 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Cartridge: 71.8 lbs. (32.6 kg)
Muzzle Velocity HE: 2,952 fps (900 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A

Range

Range with 101 lbs. (45.8 kg) HE
Elevation Distance
45 degrees 28,400 yards (25,969 m)
AA Ceiling about 50,000 feet (15,250 m)

Mount/Turret Data

Designation
  • Twin Turrets
    • Eendracht (2), Tre Kronor (2) and de Ruyter (4)
  • Triple Turrets
    • Eendracht (1) and Tre Kronor (1)
Weight Twin Turrets on de Ruyter: 113 tons (115 mt)
Triple Turrets: N/A
Elevation Eendracht Class: -10 / +60 degrees
Tre Kronor and de Ruyter classes: -10 / +70 degrees (one source says -10 / +60 degrees)
Elevation Rate N/A
Train about +150 / -150 degrees
Train Rate N/A
Gun recoil N/A

Sources

Data from:

  • "The Naval Institute Guide to World Naval Weapon Systems 1991/92" and "Naval Radar" both by Norman Friedman
  • "Cruisers of World War Two" by M.J. Whitley

Special help from Joakim Wohlfeil