Songrimsŏng-class battleship
| File:BB Songrimsong 1919.png Songrimsŏng as she appeared during the Qusayn campaign. Note decomposed Sinmun lettering.
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| Class overview | |
|---|---|
| Name: | Songrimsŏng class |
| Builders: |
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| Operators: | Greater Menghean Empire |
| Preceded by: | Hwaju-class battlecruiser |
| Succeeded by: | Anchŏn-class battleship |
| Built: | 1915–1920 |
| In service: | 1919–1944 |
| Completed: | 3 |
| Lost: | 3 |
| General characteristics (as built) | |
| Type: | Dreadnought battleship |
| Displacement: | 29,849 long tons standard |
| Length: |
list error: <br /> list (help) 212.2 m (waterline) 213.7 m (overall) |
| Beam: | 29.8 m |
| Draft: |
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| Installed power: |
46,000 shp 4 steam turbines 24 water-tube boilers |
| Propulsion: | 4 shafts |
| Speed: | 22.5 knots |
| Range: | 9,000 km at 12 knots |
| Complement: | 1,204 |
| Armament: |
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| Armor: |
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| General characteristics (1935) | |
| Displacement: |
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| Length: |
list error: <br /> list (help) 221.5 m (waterline) 224.8 m (overall) |
| Beam: | 32.4 m |
| Draft: |
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| Installed power: |
80,000 shp 4 steam turbines 8 water-tube boilers |
| Propulsion: | 4 shafts |
| Speed: | 25.6 knots |
| Range: | 9,000 kilometers at 14 knots |
| Complement: | 1,855 |
| Armament: |
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| Armor: |
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| Aircraft carried: | 1 × floatplane |
| Aviation facilities: | 1 × recovery crane |
The Songrimsŏng-class battleships, known to the Allies as the Song Lim Sohng class, were a group of three dreadnought battleships built in the Federative Republic of Menghe during the 1910s. The second battleship class to be built primarily in Menghean shipyards, they were comparable in speed, armor, and armament to the latest dreadnought battleships built in New Tyran and Dayashina, and they represented a major improvement over the preceding Chŏlsŏng-class.
Even with the Septentrion Nine-Power Naval Treaty in effect, advances in naval engineering during the 1920s and 1930s meant that newer designs quickly outpaced the Songrimsŏng-class. In the late 1920s all three ships were extensively rebuilt with an enlarged superstructure, improved torpedo protection, additional anti-aircraft weapons, and a revised bow design, which extended their useful lifetime. All three ships in the class took part in the Battle of the Portcullia Strait, where the Gyŏngsan was sunk by gunfire from Tyrannian battleships. The surviving Songrimsŏng and Daegok patrolled the coast of Khalistan until 1940, when they were transferred to Maverica before moving back to Khalistan the following year. Both were sunk by Tyrannian carrier aircraft in early 1944 while attempting to retreat to Moradabad.
Background
Following its reunification in 1901, the Federative Republic of Menghe devoted considerable effort to building up a modern navy in order to prevent a repeat of the disastrous Opium War against Sylva. Initially, it relied on foreign shipbuilders; its first two modern dreadnoughts, the Donghae-class battleships, were built in New Tyran, and the three Hwaju-class battlecruisers ordered in 1911 were built in Rajland. The battleships Chŏlsŏng and Dongchŏn were built domestically in Menghe, but this resulted in higher costs and delays.
The Songrimsŏng and her sister ships were intended as a second attempt to produce a domestically-built yet internationally competitive warship design, in an effort to reduce Menghe's reliance on foreign shipbuilders. The latter decision proved well-founded, as Rajland delayed and later suspended work on the battlecruisers Baekjin and Emil-si in order to devote more steel to the War of the Sylvan Succession. Menghean shipbuilders consulted extensively with foreign naval engineers, but due to wartime mobilization in other countries, they had to rely on domestic construction for all vessels. The first hull was laid down in 1915 at the Kimhae Naval Yard in Donggyŏng, and commissioned in 1918, one year before the war's end.
Design
Armament
The main battery of the Songrimsŏng-class consisted of twelve 35-centimeter L/45 naval guns mounted in six two-gun turrets running along the ship's centerline. All turrets could be brought to bear on the enemy in a broadside, though the center two turrets had limited firing arcs forward and aft. As built, their elevation ranged from -5 to +20 degrees, for a maximum range of 25,000 meters when firing armor-piercing shells. The total ammunition load numbered 900 shells, or 75 per gun, and was split between three magazines.
As built, the ships carried a secondary battery of twenty 15cm L/40 mod. 1915 breech-loading guns. At their maximum elevation of 18 degrees, they could reach a maximum range of 14,000 meters. The theoretical maximum rate of fire was 10 rounds per minute, but practical fire rates were closer to half that, and the recommended sustained rate of fire was 2 rounds per minute. Magazine capacity totaled 2,000 rounds.
Like many other battleships of her era, the Songrimsŏng was armed with underwater torpedo tubes, two on each broadside and one facing forward. These fired 21-inch torpedoes, with three reloads per tube in total. The torpedo storage and launch rooms were located outside the main armored citadel, and in theory would rely on 50mm deck armor above and water outside the ship for protection; plunging fire was not considered a major threat at the time.
The ships were also completed with a light anti-aircraft armament, consisting of six 7.5cm L/45 high-angle flak guns imported from Rajland and six water-cooled Vickers guns imported from New Tyran.
Protection
A 145-meter, 300-millimeter-thick main armor belt covered the full distance along the magazines, boilers, and engines, supported by a 100-millimeter upper belt and 100-millimeter forward and aft belts running along the waterline outside the citadel. Deck armor was 100 millimeters thick over the citadel and 50 millimeters thick on the fore and aft decks. Armor on the ship's guns was similar, with 300 millimeters on the barbettes, 350 millimeters on the turret faces, and 150 millimeters on the turret sides and roof. The secondary battery casemate guns had 100 millimeter cylindrical armored shields. The forward and aft conning towers were each 300 millimeters thick.
Songrimsŏng and her sister ships were built without any dedicated torpedo protection, although the space beneath the hull was divided into watertight compartments that could be sealed in the event of a torpedo or shell hit below the waterline. While anchored, docked, or moving at low speeds, the ships could deploy meshlike torpedo nets on one or both sides to stop or prematurely detonate torpedoes, but these nets could not be deployed while underway. Subsequent refits would ultimately address this flaw in the ships' construction.
Propulsion
As built, the Songrimsŏng-class were powered by 24 water-tube boilers, which were grouped between the #2 and #3 turrets. These primarily burned coal, but the coal could be sprayed with oil for additional output at high speed. Steam from the boilers was piped around the #3 and #4 turrets to four steam turbines, each of which drove a single propeller shaft. Each turbine developed 11,500 shp, and at full steam the ships could reach a top speed of 22.5 knots.
Testing and early service revealed that this powerplant configuration had the unintended effect of heating up the magazines under the #3 and #4 turrets, which had high-pressure steam piping running along either side. Though this did not heat the magazines enough to cause any accidental detonations, it did mean that propellant for these turrets' guns was kept at a different temperature, resulting in different gun performance between fore, aft, and center turrets. During their reconstruction, the ships were fitted with insulation around the #2 magazine, which partially addressed the problem.
Another issue was the placement of the forward funnel, which when sailing with a tailwind could engulf the upper half of the superstructure in smoke. A semi-spherical shield mounted atop the forward funnel in 1921 did little to abate this, and poor working conditions on the superstructure's spotting decks would remain a problem until major refits in the late 1920s.
Refits
<imgur thumb="yes" w="500" comment="The battleship Songrimsŏng as she appeared in 1935 at the outbreak of war with Sylva. Note the revised bow profile and anti-torpedo bulges.">a160yun.png</imgur> Under the terms of the Septentrion Nine-Power Naval Treaty, Menghe was allowed to conduct major refits of the Songrimsŏng in 1925, the Gyŏngsan in 1926, and the Daegok in 1927. Budget constraints led to the suspension of refit plans; the Navy wanted to take this opportunity to conduct a complete overhaul of the ships, while the legislative assembly was only willing to approve the addition of anti-torpedo bulges. Only after a military coup brought Kwon Chong-hoon to power did the Navy begin its refit program for the three ships, which were returned to active service in 1929, 1930, and 1931, respectively.
The first change was to install a new, modernized powerplant. This consisted of eight large water-tube boilers which burned oil exclusively, rather than oil-enriched coal. Combined with new turbines, these increased total output to 80,000 shaft horsepower; even with the added displacement from other changes, the ships were able to reach a top speed of 25.6 knots, just over three knots higher than their original speed. Exhaust from all boilers was channeled into a single funnel mounted just forward of the #3 turret, reducing the amount of smoke around the superstructure.
The bow section forward of the #1 turret was also entirely rebuilt to increase freeboard and seaworthiness, and to compensate for the added mass of the new superstructure, which shifted the center of gravity slightly forward. Although the enlarged bow increased displacement, it also improved the ships' L/D ratio, allowing them to get more speed out of the same engine power. As on the Chŏngdo-class battleships, a slight bulbous bow was added below the waterline, and the new bow section was streamlined to better match the distribution of the bow wave. Where the new bow merged with the existing hull, the main and upper armor belts were extended inside the hull to wrap around the forward magazines in a transverse bulkhead; the existing forward waterline armor was removed. Waterline and deck armor on the quarter deck remained in place, and an extra 50mm angled box was added over the steering engine, offering fairly high protection to the rudder and its supporting equipment.
Other changes were intended to improve the ships' protection below the waterline. Torpedo bulges with an internal vertical 50mm armor plate expanded the ships' beam from 29.8 to 32.4 meters, and used alternating air (outer) and fuel (inner) compartments to disperse the shock wave from an underwater explosion. Many of the watertight compartments were also subdivided or reinforced, especially in the old aft and new forward sections that extended beyond the anti-torpedo bulge. In the process, the underwater torpedo tubes were covered up, and the torpedo handling rooms converted to storage space. The torpedo nets, no longer deemed necessary, were removed.
Subtler changes extended the range of the ships' armament. The openings above the guns were cut further upward and the turret "stalks" were deepened, allowing the main guns to elevate to 42 degrees. At this elevation, they could throw armor-piercing shells to a range of 34,450 meters, and high-explosive shells to a range of 31,250 meters. The upper turret in each superfiring pair was also fitted with a large co-incidence rangefinder to improve accuracy at closer ranges. Even so, accuracy at long range was poor, and the ships had to rely on spotting aircraft to correct fire beyond the horizon, meaning that this range setting was mainly used for coastal bombardment work. The secondary battery mounts were similarly modified, increasing elevation to 30 degrees and range to 18,000 meters with protective canvas sleeves over the connection between the barrel and the casemate. Four secondary battery mounts were sealed due to poor firing arcs or water ingestion, but the number of 15cm shells in the secondary magazines remained fixed at 2,000.
Also fitted was a new anti-aircraft armament built around eight 100mm L/45 Type 27 guns in single mounts. These doubled as anti-ship weapons with a surface range of 12,700 meters, and they had a high rate of fire and a modernized fire-control system. For close-range defense, the ships were fitted with twelve 12.5mm heavy machine guns, which were cooled using seawater pumped from below the surface. Subsequent modernizations carried out during the Pan-Septentrion War would increase the anti-air armament even further, adding 20mm and 37mm cannons, but the anemic flak armament would remain a problem until the war's end.
More visibly, the ships were given a new superstructure built around reinforced tripod masts. This expanded the working space for officers, signal personnel, and fire-control equipment, and allowed the installation of more rangefinders for the main and secondary batteries. Though not as extensive as the pagoda mast superstructure on Dayashinese battleships of the same period, this served a similar purpose. The new superstructure carried no fewer than ten large searchlights for night combat.
To improve fleet reconnaissance and shell spotting, a single gunpowder-driven catapult carrying a floatplane was mounted atop the #3 turret. The Navy's design team chose this location as it would not interfere in the firing arcs of any of the main battery guns, but it soon proved difficult to handle, and its protrusion forward limited the #3 turret's guns to an elevation of 22 degrees. In 1934, the three Songrimsŏngs were given a modified catapult in which the forward section could fold upward in combat, allowing the guns to elevate freely.
Ships in class
- Songrimsŏng (松林城)
- Laid down in 1915 at the Kimhae Naval Yard in Donggyŏng; commissioned in 1918. Named after a minor industrial city in Menghe's northeast, she was known to the Allies as Song Lim Sohng. Soon after her commissioning, Songrimsŏng was dispatched to Qusayn to support Menghe's intervention in support of New Tyran, and while she did not see any naval combat she did fire her guns in support of the assault on Fort Schuckmann. After the reorganization of the Menghean Navy in 1924, she became the flagship of the Third Battleship Division. Songrimsŏng was only lightly damaged in the Battle of the Portcullia Strait, and with Daegok went on to continue patrol and bombardment duties around Khalistan and Maverica until her sinking in 1944.
- Gyŏngsan (勁山)
- Laid down in 1916 at the Gyŏngsan Naval Yard in the city of Gyŏngsan, for which the ship was named, and commissioned in 1919. Gyŏngsan took part in patrols along the coast of Qusayn, but she arrived too late to see combat during the War of the Sylvan Succession. She suffered heavy damage at the Battle of the Portcullia Strait, sinking a few hours after breaking away from the main line engagement due to flooding from shell hits below the waterline. Known to the Allies as Kyoung San.
- Daegok (大谷)
- Laid down in 1917 at the Kimhae Naval Yard and commissioned in 1920, Daegok was built in the same drydock used to construct the Songrimsŏng. She was named for the southwestern city of Daegok, today the 19th largest in Menghe, and known to the Allies as Tai Kok. Like Songrimsŏng, Daegok only suffered minor damage at Portcullia and remained in service with the Third Battleship Division throughout the war, only to be sunk by Tyrannian carrier aircraft in 1944.
Operational history
War of the Sylvan Succession
Of the three ships in the class, only the Songrimsŏng was complete when Menghe entered the War of the Sylvan Succession in 1918. Hoping to test the ship's combat abilities, the Menghean Navy dispatched her to Qusayn, where Menghean troops were landing along the coast in support of a Tyrannian operation to wrest control of the colony from Ostland. There, she took part in the bombardment of Fort Schuckmann, where a young Kwon Chong-hoon was injured in the ensuing assault. Both Songrimsŏng and Daegok patrolled the coast of Qusayn until the war's end, allowing the Royal Navy to focus its efforts in Casaterra.
Interwar period
Under the terms of the Septentrion Nine-Power Naval Limitation Treaty, Menghe was allowed to retain all three Songrimsŏng-class battleships, and could conduct major refits on each of them once they reached ten years since the date laid down as long as the added displacement did not exceed 5,000 tonnes. These refits did not begin until 1927, as the Navy wanted more extensive changes than the initial civilian government was willing to fund. Detailed above, the changes included improved torpedo protection, extended range for the main and secondary armament, and a rebuilt superstructure with improved spotting and fire-control systems.
Pan-Septentrion War
The Third Battleship Division engaged in combat against Sylvan capital ships sent to relieve Altagracia in 1935, and performed well. Combat experience led the Navy to refit its battleships with additional 12.5mm machine guns for close-range anti-air defense, and in 1939 they were fitted with 37mm anti-air guns as a further upgrade.
All three ships took part in the Battle of the Portcullia Strait in 1938, where the Third Battleship Division formed the tail end of the Menghean battle line confronting Task Force Q. Gyŏngsan was sunk during this engagement after sustaining multiple hits below the waterline, most of them from the battleships HMS Indomitable and Indefatigable. The Songrimsŏng and Daegok, however, emerged with only minor damage, as they had been posted at the end of the longer Menghean battle line and mainly drew fire from Tyrannian cruisers. After returning to Puerto Alegre for minor repairs and resupplying, these battleships were back in action in July of 1938, providing fire support for the Menghean landings on Portcullia.
For the rest of 1938 and into early 1940, the Songrimsŏng and Daegok conducted patrols along the west coast of Khalistan, bombarding Tyrannian coastal defenses on the shore and protecting Menghean supply vessels and troopships. While slow and ungainly, they were a major obstacle to the surviving Tyrannian warships based out of Jahrabad and the Acheron Islands, forcing the Royal Navy to organize its sorties with proper reconnaissance in order to avoid an encounter with the Third Battleship Division. In February 1940, the Third Battleship Division relocated north to Maverica to support the coastal offensive toward Baumburg, but they transferred back to Khalistan in 1941 after the Organized States declared war on Menghe, apparently out of fear that the ships were too obsolete to confront the OSN.
As Tyrannian forces advanced in Meridia, the Songrimsŏng and Daegok mostly avoided battle, moving from one safe port to another in an effort to deter direct assaults on naval bases. By March 1944, both ships were anchored at Dehra Dun, and with Tyrannian forces nearing the city they sortied in the hopes of reaching Puerto Alegre and returning to the east side of the Strait of Portcullia. The Royal Navy organized an effort to find and sink the fleeing ships, which was codenamed Operation Restitution. The ships were detected on the evening of March 24th, and on the following day they were subjected to several waves of torpedo and dive bombing aircraft. Hindered by poor anti-aircraft armament and limited land-based air support, the Songrimsŏng sunk on the 25th; the Daegok managed to beach herself in shallow water near the coast, where she persisted for several weeks as a stationary anti-aircraft platform until being disabled by dive-bombers in mid-April.
See also