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13.2:Navies
13.2:Navies

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2017-12-09

DESTROYER-ESCORT  –  LAKE  CLASS


BACKGROUND NOTES

 
    SWEDISH ESCORT    
  HSwMS Vättern (J24)  and  HSwMS Mälaren (J25)  
  The story which did happen ... outside Atlantic Air Combat  
     
     
  See also : Background Pages
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Related pages :
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A debate had been going on for some time in Sweden about whether to scrap, maintain or develop their "blue water" navy made of the 3 × Sverige class and the 2 × Tre Kronor class heavy cruisers commissioned after WW2.  In the light of Soviet military development, Sweden felt they had to further expand their own military to secure their neutrality and so decided in January 1956 to strengthen their navy.  It took the form of expending the life of the above mentioned cruiser, and acquire aircraft two carriers.  These would be of the Brithish Colossus class.

While the carriers were supposed to provide air cover for their Artic fleet, the Swedish Navy was perfectly conscious of the threat posed by aircrafts to a surface fleet.  They therefore ordered two specifically designed missile destroyers to take advantage of the RSC151 missile, initially developped by Oerlikon in Switzerland and further enhance by Bofors.  Three such destroyers had been ordered initially but the third Lake class destroyer was later cancelled notwithstanding the fact that works were well advanced.

With the help of the US Navy, Eriksbergs Mekaniska Verkstads AB developped an automatically reloading (single) launcher, very much similar to the one developped in the US for the Talos and later Tartar missiles.  A similar system was developped to handle the RIM-72 Chaparral missile system, although this was a quadruple type launcher.

To counter surface missiles, these destroyers where equipped with quad 13.2mm radar directed mountings.  Closely related to the American Maxon quads, it was a rather light system to counter anti-shipping missiles but since the system proved to be very much lethal at short range, it was adopted.

These ships may have been designed with two types of missiles, the RSC-151 actually being a dual purpose weapon, mainly a surface-to-air missile but with a secondary surface-to-surface role, but standard naval gunnery was not forgotter with two twin 120mm dual purpose turrets.

Foreign Sales

Not only Eriksbergs managed to sell a refitted Colossus carrier to South Africa but they also managed to secure the sales of the third Lake destroyer.  However, taking into account the embargo the US was implementing against South Africa, this third ship was delivered without the RIM-72 system.  Instead, South Africa asked to install one the QF2 pom-pom quad guns, of which they had plenty in storage.  The ship entered service with the South African Navy as the Walter T. Ashcroft after the name of a WW2 POW who served in the Royal Navy.

Specifications

Although the ship was classical in design, its propulsion wasn't.  Contrary to modern destroyers and frigates, the Lake class was not turbine but diesel powered with a pair of 19800KW MAN diesel.  While this propulsion setup prevented the ship to reach high speed, it offered a much larger range, ensuring that air defence was effectively offered to the carrier it was supposed to escort.  This solution was thus chosen, considering it was much more important to be able to cruise at 25 knots than jumping at 35 knots and consume all fuel.  Still, a top speed in calm sea was measured at 31 knots.

SAR - Search And Rescue (PEDRO)

The Lake destroyers were provided with an helipad but not with a hangar.   Considering these vessels were to operate along a carrier, it was considered unnecessary to supply it with hangar facilities.   But allowing a small helicopter to land on the ship was a bonus.   While its dimensions would not allow the landing of large helicopters, the helipad could nevertheless accept a variety of smaller aircrafts, either the HH-43B selected to operate from the carriers, or an Alouette III, a Westland Wasp or even a Sikorsky HSS-1

 
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