Madaesan-class cruiser

File:CA Madaesan 1932.png Madaesan as commissioned, without wartime AA improvements.
Class overview
Name:	Madaesan-class cruiser
Operators:	Greater Menghean Empire
Preceded by:	Ryangju-class cruiser
Succeeded by:	Taegisan-class cruiser
Built:	1929-1934
In service:	1932-1945
Planned:	4
Completed:	4
General characteristics Madaesan, 1932
Type:	Heavy cruiser
Displacement:	12,320 tonnes standard 13,956 tonnes full load
Length:	186.8 m at waterline 192 m overall
Beam:	20.5 m
Draught:	7.04 m (normal) 7.33 m (full load)
Propulsion:	4 sets of steam turbines, 115,000 shp total 8 three-drum boilers 4 shafts
Speed:	33.2 knots
Range:	5,000 nm (9,300 km) at 16 knots
Complement:	784
Armament:	4 × 2 200mm L/50 Type 25 naval gun 6 × 1 100mm L/40 Type 26 AA gun 6 × 1 37.5mm L/45 Type 29 AA gun 5 × 1 12.5mm MG 4 × 3 550mm trainable torpedo tube
Aircraft carried:	2 × Donghae Type 30 floatplane
Aviation facilities:	2 × catapult, 2 × recovery crane

The Madaesan-class cruisers (Menghean: 마대산급 순양함 / 馬垈山級巡洋艦, Madaesan-gŭb Sunyangham) were a group of four heavy cruisers built in the Greater Menghean Empire. Laid down in 1929-1930 and completed in 1932-1934, they were conceived of as a response to the first generation of "treaty cruisers" being built in other naval powers. Compared to the fast but thinly-armored Ryangju-class cruisers that preceded them, the Madaesan class were designed to withstand 8-inch shells at regular combat ranges, while retaining adequate firepower to defeat armor protection of their foreign counterparts and adequate speed to control engagement ranges. This resulted in a well-rounded design suitable for a variety of cruiser roles.

Background

The Selkiö Naval Treaty, signed in 1923, placed limits on new capital ship and aircraft carrier construction for all members, but did not limit the construction of ships with a standard displacement of 12,000 tonnes or below. Menghe initially responded with the Ryangju-class cruisers, which carried a main battery of 200mm guns but only had 70 millimeters of belt armor. Classified as light cruisers, they were originally intended to operate as commerce raiders, with the firepower to defeat enemy light cruisers and convoy escorts and the speed to outrun any ship capable of defeating their armor. While they accomplished this on paper, this left Menghe with no ships to engage enemy heavy cruisers directly: under Menghe's Mahanian fleet concentration doctrine, the Daegok-class battlecruisers and Chŏngdo-class battleships would never be far from the core battle fleet, and they lacked the speed to keep up with the latest heavy cruiser classes.

The new Minister of the Navy, Pak Dong-ha, responded by ordering design work on a heavy cruiser specifically designed to counter enemy heavy cruisers. Given the ambitious design requirements, the first proposal came in at over 13,700 tonnes standard displacement, well in excess of the limit imposed by the treaty. After some debate on whether to proceed with this design and claim a lower displacement, the Navy instead ordered a smaller design in compliance with the treaty.

The designers achieved the bulk of the displacement reduction by removing the torpedo defense system, which originally included a 50mm armored internal bulkhead and an integral torpedo bulge. Instead, the Madaesans would be built with a double hull with a 20mm structural bulkhead on the innermost layer. Anti-flooding protection instead mainly came via the arrangement of propulsion spaces, with alternating turbine and boiler rooms reducing the risk that a single hit would immobilize the ship.

Even after these changes, the first two ships in the class came in roughly 300 tonnes over the 12,000-ton standard displacement limit. The Navy regarded this as a small enough margin that it could not be verified by foreign intelligence, and authorized construction of the class in this state. Two ships were ordered in 1929, with two more to follow in 1930. To distinguish them from previous cruiser classes, which had been named for prefectures, the Navy named these ships for Menghean mountains.

Design

Armament

The main armament of the Madaesan-class cruisers consisted of eight 200mm L/50 Type 25 naval guns in four turrets. While the Ryangju-class turrets were twin mounts, with both guns sharing the same cradle, the turrets on the Madaesan class permitted the guns to elevate independently and even had an internal flash shield to reduce the risk of one hit or misfire disabling both guns in one turret. Turret armor measured 175mm on the face plate and 75mm on the sides, top, and rear. Though far from exceptional, the 200mm AP shell fired by these guns could easily penetrate the main belt armor of all contemporary heavy cruiser classes at ranges where the Madaesan class was relatively safe.

The main gun magazines were located in the lowest decks of the ship, to ensure maximum protection from plunging shells. A total of 160 rounds were carried for each gun, in a mixture of armor-piercing, high-explosive, and illumination rounds. The shell and powder hoists used a bucket-type system with flash protectors that covered the hoist passage for most of the cycle, preventing a gun misfire or turret penetration from igniting an explosion in the magazine. Rate of fire is listed at 3 to 4 rounds per minute, depending on the angle of the gun, as loading was performed at +5 degrees.

Madaesan and Munsusan were built with a heavy-caliber AA armament of six 100mm L/40 Type 26 naval guns in single mounts with 10mm shields to protect the crew against spray and shrapnel. While not outstanding, this was about average for cruisers of the time. Medium and small-caliber AA armament as-built consisted of six single manually-loaded 37.5mm guns and five 12.5mm water-cooled machine guns.

Torpedo armament was relatively heavy with four triple 550mm launchers, two per broadside. These initially fired the Type 23 torpedo, but by the outbreak of the Pan-Septentrion War they were usually loaded with the Type 23-II. No on-board reloads were carried, but the ships did have a fairly sophisticated system of rails on the deck to allow the reloading of all torpedo tubes from a single dock or ship alongside and the transfer of torpedoes from one side's launchers to the other's.

Protection

The Madaesan and her sister ships were among the best-protected ships in the first generation of treaty cruisers, in large part due to the Navy's requirement that they be able to withstand main battery fire from enemy heavy cruisers. Their main armor belt was 150 millimeters thick over the magazines and 125mm thick over the machinery spaces. The barbettes and conning tower were also 150mm thick. Deck armor was 75mm thick over the magazines and machinery spaces, and a 50mm box covered the steering gear.

Taken together, the components of this armor scheme allowed the Madaesans to withstand a typical interwar 8-inch SAP projectile from ranges of between 15,000 meters, below which it would penetrate the belt, and 25,000 meters, above which it would penetrate the deck. These corresponded to practical combat ranges for warships of the time, and allowed the Madaesan to engage contemporary heavy cruisers with relative impunity. Furthermore, as the ships sat low in the water, the armor belt of the magazine spaces barely rose above the waterline at full load, meaning that most 8-inch projectiles striking the ship at closer ranges were unlikely to penetrate the magazines.

Maneuverability

The Madaesan-class cruisers had a design speed of 33.2 knots, with a rated output of 115,000 shaft horsepower. They had four propeller shafts driven by geared turbine engines, with steam supplied by eight oil-fired boilers. Two small cruising turbines in the very rear could power the inner shafts at 8,000 shp total for efficient cruising. The boiler spaces and turbine spaces alternated from bow to stern, providing increased redundancy: a single bomb, shell, or torpedo hit was unlikely to disable all turbines. Additionally, watertight internal bulkheads (including a vertical bulkhead down the middle over the keel) divided the machinery section into twelve separate spaces.

The naval planners of the time, headed by Pak Dong-ha, considered the loss of speed over the Ryangju class as an acceptable tradeoff. At 33 knots, the Madaesans could still outrun or keep pace with most contemporary heavy cruiser classes, save for those built with minimal armor protection.

Operational history

The cruisers Madaesan and Baegaksan were both commissioned in 1932, three years before the outbreak of war with Sylva. Both took part in Operation Chŏng-Chŏn, the campaign to take Altagracia, where they bombarded shore positions in support of the Army's advance. Shortly afterward, on August 29th, Baegaksan demonstrated the value of the ships' heavy underwater protection when she sustained two torpedo hits from Sylvan bombers but did not experience any leakage into her vital spaces. The conditions were somewhat ideal - both torpedoes hit at the widest section of the anti-torpedo bulge, and they were WSS-vintage 18-inch torpedoes with relatively light warheads, but the incident led to high confidence in the IMN about Menghean warships' torpedo protection.

The cruiser Madaesan, by contrast, had a career crossed with ill luck. During a demonstration in January 1933, a torpedo from her forward starboard tube set fired by accident, narrowly missing the base of the pyramid mast as it skidded along the deck. As the fuse failed to arm properly, the warhead did not detonate, but the captain had to withdraw from the exercises and evacuate the ship while an ordnance disposal team came on board.

Another incident took place in September 1936, when Madaesan was undergoing refueling while at anchor in the captured harbor at Nueva Meridia. As she pulled away from the tanker alongside her, her stern brushed alongside, and her outermost starboard-side propeller cut a series of holes in the hapless vessel, spilling oil into the harbor. Fearful of the public relations consequences at home, the Imperial Menghean Navy tried to cover up the incident, blaming it on colonialist saboteurs; thus, little surviving information is available to assess what went wrong prior to the collision and why the braces over the propellers failed to stop it.

Madaesan encountered problems again two years later, during the Evacuation of Santiago. After Rear-Admiral Choe Jŏng-nam belatedly identified an unexpected formation of Sylvan battleships on the horizon, he ordered his ships to immediately turn around, setting off a chaotic scramble to change formation. In the midst of the confusion, Madaesan collided with the light cruiser Ichŏn, and the two scraped alongside each other as the Ichŏn struggled to pull away. The Madaesan suffered only minor damage during this incident, as her torpedo protection absorbed the force of the collision and prevented water from entering vital spaces, but her lighter counterpart was not so lucky. With heavy flooding in all of her boiler spaces, the Ichŏn quickly lost power and began to sink, prompting her commander to issue the order to abandon ship. During the same engagement, Baegaksan was more fortunate; a Sylvan large-caliber shell, possibly fired by a battleship, struck her above her armor belt at a shallow angle and passed clean through the ship, bouncing off the 75-millimeter armor deck without causing any damage to vital systems.

After undergoing repairs in late 1938, the Madaesan and Baegaksan spent the height of the war operating along the coast of Maverica, where their short range and low speed were less of a problem. They came under aerial attack at the First Battle of Swartzburg, though neither was seriously damaged. At Baumburg they provided coastal bombardment during the attempted Menghean breakout, though they were ultimately driven off after running out of high-explosive shells.

The cruisers' final mission took place in February 1944, as they escorted a large convoy of Menghean troop transports out of Khalistan. Columbian dive-bombers attempting to stop the evacuation struck the Baegaksan on her quarterdeck, damaging her steering motors and causing her to veer sharply to starboard. Madaesan, which was sailing in formation behind her, made a shallow turn to starboard, for reasons that remain disputed; some accounts suggest that she mistook Baegaksan's out-of-control turn for a change in formation, while others hold that her captain's orders were garbled in transmission to the backup navigation space inside the ship, leading the helmsman to turn to starboard rather than port.

Whatever the cause, Madaesan rammed prow-first into the side of the Baegaksan just aft of her #4 turret. A large portion of the latter ship's stern was sheared off, while Madaesan herself saw her bow crumple inward under the high-speed impact. With two of her propeller shafts warped by the collision, Baegaksan was unable to move under her own power, and water had flooded into her aft magazines. After coming around, Madaesan attempted to tow her to port, but the former ship's captain decided it was safer to scuttle the immobilized ship, as the entire formation was traveling in submarine-infested waters and the main priority was to keep pace with the troopships.

Madaesan herself was able to sail to Kusadasi under her own power, where port engineers patched the worst damage in her bow. She then sailed to Haeju for more comprehensive reconstruction, but remained in drydock until the end of the war, as the Navy was too weak to attempt a major confrontation and steel and fuel were needed for the Army's defense. She sustained additional damage during the atomic bombing of Haeju, which knocked her off of her supporting struts and seared the starboard side of her superstructure. After Menghe's surrender, she was lightly decontaminated and then broken up for scrap.

On closer examination of ships' logs and other records, some historians have come to the defense of the ill-fated Madaesan, noting that in each of its collision incidents the major contributing errors were made by the other ship, not the cruiser herself. She also proved herself a capable ship in surface-to-surface and surface-to-air combat, with her low, well-armored citadel providing good protection against enemy fire and her well-padded sides stopping torpedo hits on her final mission. Nevertheless, her reputation for accidents has come to outshine her combat record, and after she returned to port for repairs in 1944, some Menghean engineers and sailors regarded her as a "cursed ship."

Ships in the class

Name	Gomun	Builder	Laid down	Launched	Commissioned	Fate
Madaesan	馬垈山	Wihae Naval Yard	1929-08-28	1931-05-06	1932-08-21
Munsusan	文水山	Kimhae Capital Yard	1929-09-25	1931-09-09	1933-03-20
Jangtaesan	長泰山	Onhang Steel, Musan	1930-07-15	1933-02-07	1934-09-23
Johangsan	鳥項山	Anchŏn Naval Yard	1930-10-22	1933-02-27	1934-09-18