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.
| 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 |
| 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 |
| Elevation | Distance |
|---|---|
| 45 degrees | 28,400 yards (25,969 m) |
| AA Ceiling | about 50,000 feet (15,250 m) |
| Designation | Twin Turrets
Eendracht (2), Tre Kronor (2) and de Ruyter (4) Triple Turrets
|
|---|---|
| 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 | Tre Kronor: 10.2 degrees per second
Others: N/A |
| Train | about +150 / -150 degrees |
| Train Rate | Tre Kronor: 8.2 degrees per second
Others: N/A |
| Gun recoil | N/A |
"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
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"Kryssarna: Tre Kronor och Göta Lejon - Beskrivningar och Skötselföreskrifter" (Cruisers: Tre Kronor and Göta Lejon - Descriptions and Care Instructions) by the Royal Swedish Navy
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Special help from Joakim Wohlfeil and Alec Whalen
20 January 2007 - Benchmark
03 April 2020 - Converted to HTML 5 format