(HMS Edinburgh image). The original design called for the new Edinburgh class to be armed with four quadruple 152mm mountings, but this idea had to be abandoned as it proved impossible to build an effective quadruple turret. Instead it was decided to improve on the triple mounting design of the previous Southampton class light cruisers.(HMS Belfast image). The weight saved after abandoning the idea of quadruple mountings made it possible to reinforce the protection of the ship and install 50% more anti-aircraft weapons. After final adjustments the ships would have a standard displacement of 10,302 tons, a length of 187 meters and would be armed with twelve 152mm guns mounted in triple turrets. The maximum speed would be 32 knots thanks to increasing the power of the power plant to 82,500 shp.(HMS Belfast image). HMS Belfast began construction on December 10, 1936 at Harland & Wolff Shipyards while HMS Edinburgh began construction on December 30, 1936 at Swan Hunter Shipyards. The ships were launched on March 17 and 31, 1938, and commissioned on August 3 and July 6, 1939 respectively. The cost per ship was calculated to be about £2,140,00, including £75,000 for the guns and £66,000 for the aircraft.(HMS Edinburgh image). The Edinburgh class were very similar to the earlier Southampton class, but slightly larger. They kept the same weapons and the same main machinery, although a little more powerful. Their larger size allowed them to carry about 150 more tons of fuel oil, which improved their range by about 200 nautical miles.(HMS Belfast image). The power plant consisted of 4 Admiralty 3-drum boilers that developed 80,000shp, somewhat less than designed, but which allowed them to reach a maximum speed of 32 knots. The propulsion group consisted of 4 steam powered Parsons single reduction geared turbines coupled to 4 shafts.(HMS Belfast‘s forward engine room image). The main propulsive machinery of these ships was installed according to a system introduced by the US Navy, known as “Unit Propulsion”. This system was based on the grouping of boilers and engines into self-contained units. In this way, the propulsion system was distributed in four rooms separated by watertight compartments, two at the front of the ship and two at the rear. Each of these rooms drove its own shaft. This system ensured that no more than 50% of power would ever be lost due to a single torpedo or shell hit.(HMS Belfast‘s forward boiler room image). The boiler room had a double door system that formed a kind of airlock to prevent sudden changes in air pressure that could lead to flashes in the boilers that could incinerate those who were in front of them. The boilers burned a mixture of heavy oil called “Furnace Fuel Oil (FFO), which produced super-heated steam at a pressure of 24.5 kg/cm2.(HMS Belfast image). The Edinburgh class cruisers maintained the Southampton class protective scheme, albeit with certain areas better protected, such as the deck above the machinery (51mm non cemented armor), the deck above the 152mm shell rooms (76mm non cemented armor), and the protection deck (63mm non cemented armor. The weight of the armor represented 18.6% of the standard displacement, that is, about 1,916 tons. The maximum armor was 114mm, applied on the main belt and the command tower.(HMS Belfast image). These two cruisers were very modern ships when they entered service and were fitted with excellent electronics and fire control equipment during WWII. In 1940 HMS Edinburgh received a Type 279 early-warning radar which was replaced in 1942 by the more modern Type 273. On this date she was also fitted with a Type 284 fire control radar for the main armament and three Type 285 fire control radars for the secondary battery.(HMS Belfast in 1942 image). Likewise, HMS Belfast received an important supply of electronic equipment and radars during the repairs carried out between November 1939 and December 1942 due to the explosion of a German mine. In this period she received a Type 273 early-warning radar, one Type 284 and four Type 283 fire control radars for the 152mm guns, three Type 285 fire control radars for the secondary battery and two Type 282 fire control radars for the 40mm anti- aircraft guns. Her equipment was completed with a Type 273 general surface warning radar, a Type 281 and Type 242 air warning radars, a Type 251 and 252 sets for identification friend or foe (IFF) and a Type 270 echosounder.(HMS Belfast image). These light cruisers were heavily armed and featured a main battery consisting of twelve BL 6-inch (152mm) Mk.XXIII naval guns arranged in four triple turrets, two forward and two aft. The secondary battery consisted of twelve 4-inch (102 mm) Mk.XVI dual purpose guns mainly for anti-aircraft defense. The anti-aircraft defense was completed with the installation of sixteen 2-pounder (40 mm) “pom-pom” anti-aircraft guns in two eight-barrel mountings and two quadruple Vickers 13mm machine guns. Armament was completed with six Mk.IX 533mm torpedoes in two Mk.IV triple mounts and fifteen Mk.VII depth charges. In addition, both ships could carry two Supermarine Walrus seaplanes and a catapult for launch.(HMS Belfast‘s A & B turrets image). The BL 6-inch (152mm) Mk.XXIII guns were mounted in triple turrets which reached a weight of 175 tons. The frontal armor was 102mm and the roof and sides were protected with 51mm plates. Inside, 27 servants worked and another 22 supplied the guns with ammunition from the shell room and the magazine located several decks below. Each turret had its own shell room and magazine separated both by heavy armor. The magazines could be quickly flooded to prevent catastrophic explosions if hit by enemy fire. The turrets were designated “A” and “B” (front) and “X” and “Y” (aft).(HMS Belfast‘s A turret image). The guns measured 7.60 meters and weighed 7 tons, were of the built-up type, had 50 calibers in length and were attached to a hand-operated Welin breech block. They fired 51 kg shells at a maximum distance of 23,300 meters and this model (Mk.XXIII) had a “long trunk” ammunition hoist system that improved the speed of the hoist. The turret elevation limits were +45 degrees to −5 degrees and the guns could be loaded at a maximum angle of +12.5 degrees, but usually were loaded between +7 and +5 degrees.(HMS Belfast‘s X & Y turrets image). The maximum rate of fire of the 152mm guns was 8 shells per minute, so these ships could fire up to 96 shells per minute, or what is the same, they could send 4,896 kg of explosives towards the enemy. They used two different types of charges (cloth bags) weighing 14 kg. One was composed by cordite and the other was composed by flashless powder (NQFP) getting a muzzle velocity of 840 m/s. The barrel life was about 1,100 shots with cordite charge and about 2,200 with NQFP charge.(HMS Belfast‘s X turret image). Until 1942 the triple turrets were controlled by two Director Control Towers (DCT). On top of the castle there was one that was capable of controlling all 4 turrets simultaneously, and on the aft superstructure there was another DCT that could control the two aft turrets independently. Since 1942 the acquisition and tracking of targets for these guns were entrusted to modern fire control radars like Type 283 and Type 284.(HMS Belfast‘s 102mm dual turrets image). The original secondary battery of the Edinburgh-class cruisers consisted of twelve 4-inch (102 mm) Mk.XVI dual purpose guns in twin mounts, but this number was reduced to eight on HMS Edinburgh during WWII. These guns were mounted in “HA/LA (high angle/low angle) Mk.XIX mountings”, which allowed them to fire at a high angle of elevation, making them ideal for air defense tasks.(HMS Belfast‘s 102mm dual turret image). These guns were 4.57 meters long and weighed 2 tons and had a vertical sliding-block type manual breech. They could use two types of ammunition, a fixed QF round of 30kg and a high explosive (HE) round of 16kg at a maximum range of 18 km. In anti-aircraft role, the effective ceiling was almost 12,000 meters, with a maximum rate of fire between 15 and 20 rounds per minute. The muzzle velocity was 811 m/s.(HMS Edinburgh image). HMS Edinburgh entered service on July 6, 1939 and was assigned to the 18th Cruiser Squadron at Scapa Flow as part of the British Home Fleet. She later transferred to the 2nd Cruiser Squadron and while at the Rosyth base she suffered light damage after a Luftwaffe raid in mid-October. In late November she was dispatched with a flotilla to hunt down the German battleship Scharnhorst, but without success. From March to October 1940 she was on the river Tyne to receive some repairs and refit and after the completion of these works she was carrying out patrols through Norway and the Denmark Strait and escorting some convoys to the Middle East, Gibraltar, South Africa and the Soviet Union until January 1942.(HMS Edinburgh image). From January to early March 1942 HMS Edinburgh received a new refit on the River Tyne. Later she was escorting 3 convoys to the USSR and on April 30 while escorting the QP11 convoy back to Great Britain loaded with 4,570 kg of gold, as payment to Allies aid to the USSR, she received two torpedoes from the German submarine U-456. On May 2 while she was being towed towards Murmansk she was attacked by 3 German destroyers and received another torpedo that left her totally disabled. And although HMS Edinburgh was able to sink one of the German destroyers, she had to be scuttled by the British destroyers taking with her all the gold and the lives of 58 crew members.(HMS Edinburgh image). In 1942, HMS Edinburgh was carrying 465 gold bars for a value of 1.5 million GBP, (224 million GBP in 2023) when it was sunk. In 1954, the British Government granted permission to the British salvage company, Risdon Beazley Ltd. to rescue the treasure from the wreck, but it was not possible as it was in the Barents Sea and at great depth. Finally, in April 1981 a consortium of specialist companies began a search for the wreck of HMS Edinburgh and found it 400 kilometers (250 mi) NNE off the Soviet coast at the Kola Inlet. The ship was at a depth of 245 meters and finally on September 15 a total of 431 ingots for a value of 40 million GBP (140 million GBP of 2020) began to be extracted. In 1986, another 29 ingots were recovered, bringing the total gold recovered to 460 ingots (4,520 kg), so that the sinking only ended up producing the loss of 5 ingots.(HMS Belfast image). HMS Belfast entered service on August 5, 1939 and her first assignment was to the Home Fleet’s 2nd Cruiser Squadron. She later, like her sister HMS Edinburgh, was transferred to the 18th Cruiser Squadron at Scapa Flow. On October 9 she captured the German liner SS Cap Norte and her crew received a reward for it according to Admiralty law. Her luck turned her back and on November 21, 1939 as she was leaving the Firth of Forth she struck a German magnetic mine laid by the U-21 submarine. Although there was minor personal injuries, the damage to the rear of the ship was so extensive that it kept HMS Belfast out of action for 3 years.(HMS Belfast image). While she was in dry dock her 13mm machine guns were removed and she received 4 single and 5 twin 20mm guns. She also received an early-warning radar and several fire control radars for the artillery and a bulge was introduced into her hull amidships to improve stability. These modifications brought her standard displacement up to 11,550 tons and made her the most powerful cruiser in the Royal Navy. She returned to duty in December 1942 and was sent to escort convoys in the Arctic.(HMS Belfast image). HMS Belfast spent all of 1943 escorting convoys in the Arctic. In June she received a new refit and 4 single 20mm guns were installed and her reconnaissance seaplanes were removed. In December 1943, the German Admiral Doenitz was urged to cut off the movement of Allied convoys with help for the USSR and for this purpose a squad formed by the battleship Scharnhorst and 5 destroyers was sent to the North of Norway to intercept the JW55B and RA55A convoys. This operation would end up giving rise to the Battle of the North Cape, the final battle of battleships in European waters.(HMS Belfast‘s A & B turrets image). Thanks to the fact that British intelligence had intercepted and deciphered the German orders, the Home Fleet set up an ambush for the unsuspecting Germans. Two squadrons were formed, the 10th Cruiser Squadron (Force One) with the cruisers HMS Belfast, (as Flagship), HMS Norfolk, HMS Sheffield and three destroyers and another group (Force Two) that included the battleship HMS Duke of York and the cruiser HMS Jamaica with four destroyers. The plan for the British Force One was to escort convoy JW55B, attracting the Scharnhorst to them, while Force Two cut off their retreat and attacked from the south. The Force One was commanded by Vice Admiral Robert Burnett and Force Two was commanded by Admiral Sir Bruce Fraser, who was aboard the battleship HMS Duke of York.(HMS Belfast‘s B turret image). Finally, on December 25, 1943, the Scharnhorst and 5 destroyers set sail from Altafjord, Norway, under the command of Rear Admiral Erich Bey to intercept the convoy. In the early hours of the 26th the British were aware of the German movements and awaiting the attack, but due to bad weather the German ships did not find their target. Scharnhorst dispatched her destroyers to the south to widen the search area, losing contact with them. The British ordered convoy RA55A to move north from the area and JW55B to turn around so they could approach with Force Two. Four escort destroyers from convoy RA55A joined Force Two to reinforce the attacking force.
