Hanmaesan-class cruiser
 | This article is incomplete because it is pending further input from participants, or it is a work-in-progress by one author. Please comment on this article's talk page to share your input, comments and questions. Note: To contribute to this article, you may need to seek help from the author(s) of this page. |
| <imgur w="300px">Tz09t4F.png</imgur> Hanmaesan as she appeared at the Battle of Swartzburg.
| |
| Class overview | |
|---|---|
| Name: | Hanmaesan-class cruiser |
| Operators: | Greater Menghean Empire |
| Preceded by: | Hasŏlsan-class cruiser |
| Succeeded by: | none |
| Built: | 1937-1942 |
| In service: | 1940-1945 |
| Planned: | 4 |
| Completed: | 3 |
| Cancelled: | 1 |
| Retired: | 3 |
| General characteristics Hanmaesan, 1940 | |
| Type: | Heavy cruiser |
| Displacement: |
list error: <br /> list (help) |
| Length: |
list error: <br /> list (help) |
| Beam: | 22.8 m |
| Draught: |
list error: <br /> list (help) |
| Propulsion: |
list error: <br /> list (help) |
| Speed: | 34.9 knots |
| Range: | 6,500 nm (12,000 km) at 15 knots |
| Complement: | 1,160 |
| Armament: |
list error: <br /> list (help) |
| Aircraft carried: | 3-5 × Yusin Type 40 floatplane |
| Aviation facilities: | 2 × catapult, recovery crane, hangar |
The Hanmaesan-class cruisers Menghean: 한매산급 순양함 / 寒梅山級巡洋艦, Hanmaesan-gŭb Sunyangham) were a group of heavy cruisers built for the Imperial Menghean Navy during the Pan-Septentrion War. Four were planned in total, but only three were completed before the war's end, with the fourth hull broken up for scrap between 1943 and 1944. All three survived to the war's end, though the Godongsan suffered severe torpedo damage in 1945. The surviving ships were decommissioned after Menghe's surrender, with the Godongsan and Yaksusan sold for scrap and the Hanmaesan expended as a target in a nuclear weapons test.
Widely considered the pinnacle of Menghean wartime cruiser design, the Hanmaesan-class vessels combined above-average protection, strong anti-air defenses, a formidable main battery, and long-range torpedoes in a reasonably fast hull. Military historians rank them among the most effective heavy cruisers of the Pan-Septentrion War, excluding vessels with a main gun caliber of over 203 mm. These capabilities, however, required a demanding increase in size: with a full-load displacement of over 20,000 tonnes, the ships were on par with the Unmunsan-class super-heavy cruisers. Given the limits of Menghean shipyards and the expanse of ocean the IMN had to contest, this was a questionable investment, especially given that the cruisers themselves saw relatively little surface action over the course of the war.
Development
Throughout the interwar period, Menghe's ship construction program had been constrained by the terms of the Septentrion Nine-Power Naval Limitation Treaty, which, among other things, stipulated that heavy cruisers could not displace more than 12,500 tonnes at standard load. The Madaesan and Taegisan class cruisers were all built to this limit, with the exception of Obongsan, which was modified late in construction to carry additional anti-air guns. In an effort to compensate for Menghe's smaller cruiser limit, the Navy demanded heavier armament and a higher speed for the Hasŏlsan-class cruisers, which ended up exceeding their official displacement by some 3,000 tonnes. Yet even at this expanded size, the Hasŏlsans made a number of structural sacrifices to minimize weight, and the Navy considered them compromise designs.
With the collapse of the treaty system in the summer of 1935, Menghe was free to expand its shipbuilding program without quantitative limits. The Navy's design team at Sunju promptly began drawing up plans for an "improved" Hasŏlsan design, which would have a more generous displacement and improved protection. As with previous designs, the Navy sought to build a cruiser which was individually superior to any of its foreign contemporaries, so that if a formation led by a Hanmaesan encountered an enemy cruiser patrol it would hold the upper hand in the engagement.
Combat experience off the coast of Innominada had already revealed the importance of a strong anti-air defense, so the Navy augmented the new cruiser's long-range AA guns, using the 130mm L/55 Type 32 naval gun in dual-purpose mounts as introduced on the Hyangchun-class battleships. The recently introduced Type 38 anti-aircraft gun, including its remotely aimed mount, and Type 40 anti-aircraft autocannon were both integrated into the design. Also significant was the introduction of the Dayashinese Type 91 torpedo, which in 1938 had its blueprints licensed to Menghe after the latter entered the war against New Tyran.
All of these new developments required modifications to the design, and added to delays in its development. The first ship in the series was only laid down in 1937, and it took three years to complete. An earlier entry to service probably would not have been decisive, given the uneven nature of Menghe's first confrontations with the Organized States, but the commissioning of the Hanmaesan in late 1940 and her sister ships even later limited their usefulness in the conflict.
Design
Armament
The main battery was directly carried forward from the preceding Hasŏlsan class. It consisted of twelve 20cm L/55 Type 34 naval guns in four three-gun turrets, which were capable of independently elevating and firing their guns. The ammunition load was increased to 150 rounds per gun, and the guns themselves were chrome-lined for a longer barrel life, an improvement over the first batch of guns for the Hasŏlsans (their replacements were of the lined type). Official Menghean sources claim a rate of fire of 3-4 rounds per minute, in line with 8-inch guns in other navies, and a range of 27,150 meters at a maximum elevation of 40 degrees.
The secondary battery brought more interesting changes. In place of the open-backed 100mm L/40 twin turrets standard on preceding Menghean cruisers, the Hanmaesans carried sixteen 130mm L/55 Type 32 naval guns in dual-purpose mounts. Eight of these were in centerline quadruple turrets, technically "double twin" mounts each carrying two pairs of closely mounted guns in joined sleeves. This arrangement meant that a single Hanmaesan could point twelve 130mm gun barrels to either broadside. Compared to the 100mm guns, the 130mms had a heavier shell and a higher muzzle velocity, resulting in a longer range and greater accuracy. Anti-surface performance also improved considerably over the 100mms, with a maximum range of 25,700 meters and reasonable anti-armor performance. Rate of fire remained impressive at 10-12 rounds per minute due to assisted loading and mechanized shell hoists. The main drawback of this new arrangement was weight: the quadruple turrets were large and heavy, with a wider basket diameter than the 200mm turrets, and required tall barbettes in order to fire over the B and C turrets. The superfiring quad turret design was one of the main reasons for the Hanmaesans' large increase in size over their predecessors.
Lighter anti-air guns also brought a marked improvement over preceding Menghean cruisers. As completed, Hanmaesan carried a formidable battery of Type 38 anti-aircraft guns, though all were in the D-type twin mount which had manual traverse controls. Yaksusan, commissioned in 1941, was the first Menghean warship to use the new R-type mount, which had powered controls and could be aimed from a separate fire-control director. Hanmaesan was modified for the R-type mount later in the same year, and Godongsan was completed with it in 1942. In 1944, all three ships were refitted to carry a combination of R-type and B-type mounts, the latter carrying quadruple 37mm guns with further improvements to the fire-control system. Small-caliber AA underwent a similar process of improvement, with the number of 20mm Type 40 AA guns steadily increasing over the course of the war.
This impressive gun armament was accompanied by a no less impressive torpedo armament. The Hanmaesans carried a total of sixteen 610mm torpedo tubes in four side mounts. With a range of 40 kilometers at 36 knots or 20 kilometers at 48 knots, these made the heavy cruisers into a formidable threat for enemy capital ships. Sixteen additional torpedoes were carried at deck level in a reload mechanism modified from Dayashinese blueprints: with the launcher traversed away, the rear of each tube was opened and a cable run through to pull the reserve torpedo into position. After operational service revealed that the oxygen-fueled torpedoes were prone to catastrophic explosion when hit by bombs or shells, Menghean engineers drew up a second chain mechanism which could drop all stored torpedoes through large side hatches in the event of a fire or aerial attack, and fitted it to the three cruisers during their 1944 AA refits.
Protection
The Hanmaesans brought significant upgrades in shell and torpedo protection when compared to their immediate predecessors, which had made sacrifices in this area in order to minimize displacement. Their overall armor requirements were comparable to those on the Taegisan-class cruisers: protection against 8-inch armor-piercing projectiles over a range of 15 to 25 kilometers. As on the Taegisans, this was accomplished by means of a 150mm belt and a 75mm deck. The main belt was angled inward at 25 degrees, increasing its effective thickness, especially against descending shells. As on the Hasŏlsans, however, the magazines were placed entirely below the waterline for greater protection, and the armor belt only extended above the waterline around the boilers and turbines. The forward and aft ends of the citadel were protected by 150mm vertical plates. The funnel uptakes were protected by 50mm armor.
Protection for the main battery turrets was similar. The barbettes were 150mm thick, the turret faces 200mm thick, and the turret sides and roof 100mm thick, with a 75mm rear plate. Other than the slightly increased front, rear, and roof armor, the turret geometry was identical to that on the Hasŏlsans. The secondary battery turrets also had relatively impressive armor: 75mm on the face and 50mm elsewhere. The barbettes and handling rooms were protected by 75mm armor. The conning room underneath the bridge had 200mm armor on the front and sides with a 150mm rear. The fire-control towers for the primary and secondary armament had 20-50mm armor, mainly to protect against shell splinters and strafing aircraft.
Underwater protection was increased during the design process, with the hull expanded to form anti-torpedo bulges which ran seamlessly into the hull sides. The basic configuration of the underwater protection system was carried forward from the Hasŏlsans, with a 50mm bulkhead running vertically from the base of the main belt to the bottom of the hull, separating a fuel-filled interior compartment from a layer of air-filled compartments on the outside. The improvement over the Hasŏlsans came in the thickness of the overall scheme; the air-filled compartments were 0.7 meters wider on each side, and the bracing on the joint between the bulkhead and the armor belt was stronger. Two of the three ships in the class, Godongsan and Yaksusan, sustained torpedo hits during their careers but were able to return to port for repairs.
Propulsion
The powerplant for the Hanmaesans was directly carried forward from their predecessors with minimal changes. Twelve water-tube boilers trunked into a single funnel were connected to four steam turbines developing a total of 150,000 shaft horsepower. The omission of centerline watertight bulkheads in the boiler rooms proved fortunate at the Battle of Hwangsa Bay, where Godongsan suffered a torpedo hit which caused flooding in two boiler rooms but did not induce a serious list.
Increased displacement between the Hasŏlsans and Hanmaesans did limit the effectiveness of this 150,000 shp powerplant, with the latter class only able to achieve 34 knots at top speed. This was still reasonably fast, enabling the Hanmaesans to keep up with most enemy cruisers and narrowly outrun all enemy battleships.
Aircraft
The Hanmaesans were the first and only Menghean heavy cruisers to feature an internal hangar; all of their predecessors had carried their aircraft on an external servicing deck. The layout of the hangar was borrowed from the Hyangchun-class battleships, commissioned around the same time, and made use of the open space inside the wide transom stern. One floatplane was stored on top of a centerline elevator underneath a sliding metal roof, and two more were stored side-by-side in front of it on metal tracks for easy movement. Two additional floatplanes could be stored on top of the catapults for a total of five, though late in the war the catapults were usually left empty as muzzle blast from the rear guns could damage the planes.
As on the Hyangchun-class battleships, the reconnaissance aircraft were Yusin Type 40 floatplanes, a single-engine three-seater design. Its wings could fold upward just beyond the twin float struts, allowing for easy hangar storage. The Yusin Type 40 also had a higher speed and a longer range than the preceding Namtong Type 36, though it was still vulnerable to enemy patrol aircraft.
Ships in the class
See also