Baekjin-class battlecruiser
| Class overview | |
|---|---|
| Operators: | Menghe |
| Preceded by: | none |
| Succeeded by: | Daegok-class battlecruiser |
| Built: | 1911-1914 |
| In commission: | 1914-1923 |
| Planned: | 4 |
| Completed: | 2 |
| Cancelled: | 2 |
| Scrapped: | 2 |
| General characteristics | |
| Type: | Battlecruiser |
| Displacement: |
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| Length: |
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| Beam: | 20.97 m |
| Draught: |
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| Propulsion: |
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| Speed: | 27.2 kts |
| Range: | 3,700 nmi at 14 kts |
| Complement: | 773 |
| Armament: |
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| Armour: |
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| Aircraft carried: | none |
The Baekjin class were a pair of battlecruisers built for the Menghean Navy in the 1910s, shortly before the War of the Siennese Succession. They were designed and constructed in Hallia to a set of general specifications originating in Menghe. Using the old Stuart-Lavender romanization system, they are sometimes known as the Paik Chin class.
The Baekjins were Menghe's only "true" battlecruisers, with a slightly lightened main battery of eight 28cm guns in an all-centreline arrangement and a cruiser-like armor scheme that featured a six-inch main armor belt and a three-inch deck. These sacrifices allowed them to attain a top speed in excess of 27 knots, enough to outrun all existing battlecruisers at the time of their design. They were intended to be used as commerce raider support ships, hunting down enemy armored cruisers in order to clear the way for other cruisers to attack enemy shipping. The Kongō-class battlecruisers, ordered simultaneously with the Baekjins, rendered them obsolete in this role, and motivated the design of the Daegok-class battlecruisers.
Both the Baekjin and the Pyŏng'an saw operational service during the War of the Siennese Succession, where they escorted convoys in the South Menghe Sea and provided fire support during joint Anglo-Menghean operations in the Ostish colony of Kussein. They received modest refits during this conflict, sporting light anti-aircraft guns and torpedo nets. Under the Selkiö Naval Treaty, Menghe agreed to scrap both ships, which were already obsolete and ill-suited for major refits.
Development and construction
During the 1900s and early 1910s, the Menghean naval establishment increasingly leaned toward the Jeune École school of naval strategy as a solution to the disparity in battle fleet size between Menghe and its likely rivals. Menghean politicians and strategists generally identified Dayashina as the greatest threat to Menghe during this period, citing its recent colonial expansion in Southeast Meridia and the war scare during the Polvokian Revolution. Dayashina was also the only major power whose core territories lay close to Menghe, and which Menghe could thus reasonably threaten with commerce raiding. At an inaugural meeting in November 1909, the new Minister of the Navy proposed using fast cruisers based in Maracaibo or Sundan to intercept shipping between Dayashina and its resource-rich colonies of Kainan and Shijuku, which were the Dayashinese Empire's main sources of imported food and raw materials.
The Baekjin-class battlecruisers, developed under the project name Plan 7, were meant to serve as the centerpiece of this strategy. As designed, they would be fast enough to easily outrun nearly all of the Imperial Dayashinese Navy's large warships, including the Ibuki-class "large armored cruisers." This would allow them to overtake and sink protected cruisers like the Tone and Niikata class, while also running away from any capital ships large enough to seriously threaten them. In this manner, they would pick off the IDN's most threatening escorts, leaving Dayashinese convoys vulnerable to attacks by Menghe's own cruiser fleet. This made the Baekjins "true" battlecruisers: ships that combined a capital-ship-grade main armament with an armored-cruiser-grade protection scheme, designed for commerce raiding and reconnaissance, but not designed to stand in the battle line.
Because Menghe still lacked the industrial base to build such a large and state-of-the-art capital ship at home, the Menghean Navy approached various Casaterran navies with general design plans to solicit a shipbuilding contract. After a contentious and possibly corrupt bidding process, the contract was awarded to a Hallian shipyard, which promised the highest-quality steam turbines and already had a 28-centimeter gun in service. Two ships were laid down on 6 May and 20 June 1911, with an option for two more of an improved design to follow in 1913. This option was later rejected, owing to news of the construction of the Kongō-class battlecruisers, which outclassed the Baekins in nearly every way. Despite being laid down over a month later, the Pyŏng'an was finished first on 25 January 1914 and delivered to Menghe on 2 April of that year. Her sister ship was delivered nine days later. Despite this timeline, the pair are still most commonly known as the Baekjin (or Paik Chin) class.
Design
Overall characteristics
The Baekjin-class battlecruisers measured 178.3 m (585 ft) at the waterline and 179.5 m (589 ft) long overall, with a beam of 20.97 m (68.8 ft) and a deep-load draft of 8.44 m (27.68 ft). They displaced 15,982 long tons at full load, or 13,930 tonnes standard displacement. Altogether, they were relatively light, with reasonably good seakeeping save for the low-lying casemates.
Propulsion
The Baekjins were propelled by four direct-drive steam turbines, each coupled to a single shaft. A mix of low-pressure and high-pressure turbines allowed some balancing of performance at low and high speeds. At full output, this powerplant could generate 58,000 shaft horsepower, for a top speed of 27.2 knots.
Steam for this powerplant came from 24 water-tube boilers split across four boiler rooms, with the central two boiler rooms trunked into one funnel. This distributed boiler room layout provided some measure of survivability against flooding and shell hits, as any one hit was unlikely to damage more than one-quarter or one-half of all steam power. The Baekjins were the first Menghean capital ships to pioneer hybrid-fuel boilers: the boilers primarily burned coal, but the coal could be sprayed with heavy oil to increase the burning temperature. Fuel oil only accounted for 10% of the bunker weight on the Baekjins, so this coal-oil combination would likely be reserved for high-speed sprints, with coal (which Menghe could mine domestically) otherwise burned exclusively.
The ships' range was respectable, officially cited as 3,700 nautical miles (6,850 km) at 14 knots or 8,000 nautical miles (14,800 km) at 10 knots. This was initially deemed adequate for their likely mission profile, which would involve round-trip raids with refueling stops in Maracaibo or Sundan, but was also far surpassed by the range of the Kongō class.
Armament
The main battery of the Baekjin-class battlecruisers consisted of eight 28cm/45 Mark 2 guns in four two-gun turrets. These turrets were arranged along the centerline, and had good firing angles, with all turrets able to fire 30 degrees off the centreline both fore and aft. These steep firing angles, however, were found to cause blast damage to the superstructure, boats, and boiler intakes, and in practice maximum firing angles on the main battery turrets were recommended to stay over 45 degrees off-centreline. The A and X turrets had 280 shells in their magazines, and the M and Q turrets 200 shells, reflecting an expectation that these turrets would see less use in pursuits, but still significant firing overall.
The secondary battery consisted of eighteen Menghean-designed Type 10 125mm L/45 guns in Type 11 casemate mounts. These were meant to fill the role of both a secondary and a tertiary battery, and as designed, the Baekjins carried no lighter gun armament. The Type 10 gun was reasonably well-liked overall, but the Type 11 casemate mount was not watertight, with a loose fit overall, open slots for sighting equipment, and gaps between the casemate armor and the armor belt at maximum fore or aft traverse. The 3rd, 4th, and 5th casemate pairs, in particular, were very uncomfortable to operate, and nearly useless at high speeds or in heavy seas. The four forward-facing casemates were raised one deck, which moderately improved their serviceability. Ammunition stowage for the casemate guns totaled 3,240 rounds, or 180 rounds per gun.
In addition to their guns, the Baekjin-class battlecruisers were completed with five torpedo tubes: two on each beam under the conning tower, all sharing the same internal compartment, and one facing aft behind the steering compartment. Reload storage totaled two torpedoes per tube.
The Baekjin-class battlecruisers were the last Menghean capital ships to be built with a ram bow. This feature was already largely vestigial, and some early design proposals omitted it entirely. Ostensibly, it provided a way for a Baekjin-class battlecruiser to inflict damage on capital ships which its smaller guns could not penetrate; but official doctrine was to flee from such threats if possible, and closing to ramming distance instead would expose the ship to enemy fire on its approach.
Protection
The main armor belt of the Baekjin class was 150mm (5.91 in) thick and 109.4 m (359 ft) long, covering the magazines, machinery spaces, plotting rooms, and torpedo rooms. The upper belt, which covered the casemates and their reloading spaces, was 100mm (3.93 in) thick, and also enclosed the upper casemate section for the raised forward secondary guns. The fore belt was also 100mm thick, and ran all the way to the reinforced ram bow; the aft belt was also 100mm thick, and ran to the end of the steering gear room, but did not cover the aft torpedo room. The forward conning tower had an impressive 300mm of armor; the aft conning tower, 125mm. The main battery armor was 200mm (7.87 in) thick on the turret faces and barbettes, 125mm on the turret sides and rear, and 75mm on the turret roofs; the casemate gun shields were 75mm thick.
Vertical protection was relatively impressive, with the main armor deck measuring 50mm (1.96 in) over the quarterdeck and citadel, and 30mm (1.18 in) over the forecastle. The casemate deck had an additional upper deck measuring 25mm (0.98 in) thick, for a total of 75mm of armor protection over the ship's citadel. This vertical armor scheme was relatively generous for a battlecruiser of the era, and would have allowed some freedom to engage large armored cruisers at long range. At close ranges, however, the weak horizontal protection prevented these ships from fighting effectively in the battle line.
As built, the Baekjins' torpedo protection was virtually nonexistent. The outer double hull was only 1.7 meters (5.6 feet) thick at maximum, and its inner bulkhead was built from soft structural steel rather than armor plate. A mine strike or torpedo impact anywhere along the citadel would have all but guaranteed flooding of the magazines or machinery spaces, with little except transverse bulkheads to contain the damage.
Operational service
Both the Baekjin and the Pyŏng'an were delivered to Menghean naval service in April 1914. They would be the Menghean Navy's most capable capital ships until April 1919, when the Songrimsŏng-class battleships finished their working-up.
In August-September 1915, in response to the outbreak of the War of the Siennese Succession, both ships were refitted with torpedo nets to protect them against submarine attacks while in port.
In 1917, in response to reports of the growing role of reconaissance airships and light bomber aircraft, both ships were refitted with 12-pdr 20cwt quick-firing high-angle guns. These mounts were initially installed at main deck level port and starboard of the forward funnel, restricting the firing arcs of the M turret, which was already restricted from firing forward at its greatest possible angle to avoid damaging the superstructure. Four Maxim guns on high-angle mounts were also installed around the ship for close-in anti-air defense.
In 1920, the ships underwent a somewhat larger refit which moved the 12-pdr 20cwt high-angle guns to elevated platforms, increased the number of anti-aircraft machine guns, added glass windows and steel roofs to the wheelhouse, and added a centralized fire-control system. More thorough refits were discussed, including a total replacement of the powerplant and the installation of anti-torpedo bulges. As preliminary negotiations for the Selkiö Naval Treaty began, however, the Menghean Navy declined to upgrade the Baekjins further, in anticipation of their likely disposal. Instead, both ships were moved into reserve status. At the treaty negotiations, Menghe happily agreed to scrap both Baekjins, and they were formally decommissioned in October 1923.
Ships in the class
The table below lists the construction times and eventual fates of the two Baekjin-class battlecruisers. Both ships were named for Menghean cities formerly at the frontiers of the core Meng region: Baekjin in the northeast, and Pyŏng'an in the southwest. Until the introduction of the Romaja romanization system in 1933, these ships' names were listed in Anglian and other foreign sources using the Stuart-Lavender romanization system; the Menghean pronunciation is the same.
| Ship name | Stuart-Lavender | Gomun | Laid down | Launched | Completed | Delivered | Fate |
|---|---|---|---|---|---|---|---|
| Baekjin | Paik Chin | 白津 | 1911-05-06 | 1912-10-23 | 1914-02-06 | 1914-04-11 | Decommissioned 1923-10-10; sold for scrap |
| Pyŏng'an | Phioung Ahn | 平安 | 1911-06-20 | 1912-11-13 | 1914-01-25 | 1914-04-02 | Decommissioned 1923-10-10; sold for scrap |