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De Zeven Provincien class

Light cruiser

Almirante Grau | De Zeven Provincien class

The Almirante Grau of Peruvian Navy is the world's only "gun cruiser" still in service

 
 
Entered service 1953
Crew 653 men
Sea endurance 90 days (?)
Dimensions and displacement
Length 187 m
Beam 17.25 m
Draught 6.72 m
Displacement, standard 9 681 tons
Displacement, full load 12 165 tons
Propulsion and speed
Speed 32 knots
Range up to 7 000 nm at 12 knots
Propulsion 4 boilers supply steam to 2 turbines developing 85 000 shp and driving 2 shafts
Aircraft
Helicopters 3 (Aguirre only)
Armament
Artillery 8 x Bofors M42 152/53 guns (4 on Aguirre), 4 x OTO Melara 40L70 DARDO guns
Missiles 8 x Otomat Mk.2 anti-ship and costal attack missiles
Armor
Hull belt 50-76 mm
Conning tower 50-125 mm
Turrets 50-125 mm
Decks 20-25 mm

 

   The last of a dying breed, the De Zeven Provincien class light cruisers are the world's only remaining operational "gun cruisers". In fact, regarding their ability to perform extremely heavy gunfire bombardments, survive direct hits due to their armor, and perform protracted high-speed independent actions at sea, these vessels are in a sense the *only* cruisers still in service.

   The history of these warships is just as unusual as their presence in a modern navy. They were originally laid-down in 9 May 1939 (De Zeven Provincien) and 5 September 1939 (De Ruyter), and were meant to replace the elderly and lackluster Java class light cruisers. They were not only built with a much larger main battery than the Javas, but also with much more powerful guns that had a secondary anti-aircraft capability badly needed by the Dutch Navy at the time. These vessels were only partially complete when the Netherlands were invaded by Germany on 10 May 1940. The Kreigsmarine attempted to complete work on the De Zeven Provinciens for their own use, but every attempt by the Axis to complete their construction during the war failed, thanks in part to sabotage by the Dutch resistance. After the war, the damage from sabotage and the elements was deemed light enough for the project to be restarted, and the De Zeven Provinciens were re-designed to a radically modified configuration.

   Interestingly, the names of these ships were changed repeatedly throughout their construction. The first vessel was to be named the Eendracht, and the second was to be the De Zeven Provincien. In a strange twist of fate, the Eendracht received the name originally reserved for her sister ship, which was re-named the De Ruyter. Also unusual is that the De Ruyter was actually commissioned a month earlier (18 November 1953, versus 17 December 1953), but the De Zeven Provincien remained the name-ship. Another irony is that the M42 152/53 main guns used on the De Zeven Provinciens were not the examples originally ordered for them, but rather duplicates built later after the war. The originals instead ended up on Sweden's Tre Kronor class light cruisers, which like the De Zeven Provinciens were long-lived in operational service.

   Both vessels participated in numerous NATO exercises in the 1950s, 1960s, and early 1970s. The De Zeven Provincien's aft main battery was replaced in 1964 by launchers for the RIM-2 Terrier SAM; this was meant to be repeated on the De Ruyter, but her conversion was cancelled for financial reasons.

   The De Ruyter was decommissioned from the Dutch Navy in 1973, followed by the De Zeven Provincien in 1976. Both were purchased by the Peruvian Navy the same year they were decommissioned in the Netherlands, and were re-named the BAP Almirante Grau and BAP Aguirre, respectively. The Aguirre was soon after laid-up for the removal of her Terrier launchers, and the aft deck was in their place converted into a landing pad for 3 helicopters. Further upgrades also saw the addition of Otomat anti-ship missile launchers, which greatly expanded the utility of these warships. However, additional upgrades planned in the 1990s all came to grief for lack of funding.

   The M42 152/53 guns are all mounted in armored twin-gun turrets, which can traverse up to 150 degrees to either side, and elevate from between -10 and +70 degrees. The elevation and traversal rates are unpublished. The maximum range for the M42 is 25 969 m with an AP round, and it has an anti-aircraft ceiling of up to 15 250 m with an HE round (see below for information on the ammunition). The loading system is fully-automated, but can be cycled manually at a slower rate in the event of battle damage or a malfunction. The rate of fire is 10 rounds/minute/gun with AP rounds, or 15 rounds/minute/gun with HE rounds. The effectiveness of this weapon against missiles and modern aircraft is unclear, but its range, power, accuracy, and rate of fire are not to be underestimated. It is beyond dispute however, that this would be still devastating against ships and shore targets.

   The ammunition for the M42 is highly unusual, in that while the projectile and charge are stowed separately, they are rammed together immediately prior to loading to essentially form a unitary cartridge. There are two projectiles for this weapon; a 46.7 kg AP round with a 45.8 kg HE round (also often called an "AA" round), the latter of which has an air-bursting capability for use against aircraft. The ammunition stowage per-gun is also unpublished, but is presumably about 150 rounds/gun, as with other light cruisers from this era.

   As is typical of Dutch capitol ships, the De Zeven Provinciens are very lightly armored, though these "tinclad" cruisers ironically had the last laugh in the matter; today, the Almirante Grau is the only warship in active service with *any* armor at all. The armor arrays on this class are composed of KCA (Krupp Cemented Armor) steel, varying wildly in thickness from one area of the ship to another. The most exposed areas of the conning tower and the turret faces are 125 mm thick, but the hull belt is only up to 76 mm thick, and the rest of the armor is only between 20 mm and 50 mm thick. However, each of the top two decks of the hull is armored, giving substantial protection from vertical attacks as a result of a spaced armor effect. No data has been published on the thickness of the barbettes, but if most other Light Cruisers are any indication, it is likely quite thin.

   The propulsion system is a product of a bygone era as well, as few warships introduced since the 1960s employ steam propulsion. 4 Werkspoor-Yarrow three-drum boilerssupply steam to 2 De Schelde Parsons geared steam turbines, delivering 85000 shp and driving 2 shafts. Between the ship’s provisions for the crew and 1750 tons of oil for the boilers, the De Zeven Provinciens can steam up to 7 000 nautical miles (13 000 km), and remain at sea for several months on-end.

   The Otomat Mk.2 anti-ship missile is a sea-skimming, fire-and-forget weapon, weighing 770 kg and carrying a 210 kg HE-FRAG warhead. Its speed and range are exceptional for its class, at 310 m/s and 180 km, respectively. The guidance system is a combination of inertial navigation system and active-radar-homing. It is not clear whether the Peruvian Navy uses the Block I, Block II, or Block III variants of the Otomat Mk.2. A total of 8 Otomats were carried each on the Almirante Grau and Aguirre.

   As of late 2014, the Almirante Grau is still in active service. The Aguirre was decommissioned and laid-up in 1999, and has apparently decayed considerably. It was scrapped in 2000. Without any affordable option for a cruiser to replace them, and no light cruisers in development (nor even planned), no replacement is possible for the Almirante Grau and Aguirre. The eventual retirement date of the Almirante Grau is unknown, as is their eventual fate after being stricken from the Peruvian Navy. Presumably it will also be scrapped, as with every other cruiser retired from the South American navies in the past.

 

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In Royal Netherlands Navy service

 

Name Laid down Launched Commissioned Status
De Zeven Provincien (C-802) 1939 1950 1953

decommissioned in 1976, sold to Peru

De Ruyter (C-801) 1939 1944 1953

decommissioned in 1973, sold to Peru

 

In Peruvian Navy service

 

Name Laid down Launched Recommissioned Status
BAP Aguirre (ex-De Zeven Provincien) (CH-84) 1939 1950 1978

decommissioned in 1999, scrapped in 2000

BAP Almirante Grau (ex-De Ruyter) (CLM-81) 1939 1944 1973

active, in service

 
Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class


 
Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class

Almirante Grau | De Zeven Provincien class


 
Almirante Grau | De Zeven Provincien class

Aguirre | De Zeven Provincien class

Aguirre | De Zeven Provincien class

Aguirre | De Zeven Provincien class

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