Asama-class cruiser
| Company type | Warship class |
|---|---|
| Industry | Naval shipbuilding |
| Founded | Late 1890s |
| Headquarters | United Kingdom |
| Products | Armored cruisers |
Overview of the Asama-Class Armored Cruisers
The Asama-class armored cruisers (浅間型装甲巡洋艦, Asama-gata sōkōjun'yōkan) consisted of two vessels constructed for the Imperial Japanese Navy (IJN) during the late 1890s. Due to Japan's limited industrial capabilities at the time, these warships were commissioned and built in the United Kingdom. They formed a critical component of the "Six-Six Fleet" initiative, which was launched following Japan’s victory over China in the First Sino-Japanese War (1894–95). Both sister ships were actively engaged in all four principal naval engagements of the Russo-Japanese War (1904–05): the Battle of Port Arthur, Battle off Ulsan, Battle of the Yellow Sea, and Battle of Tsushima. However, their involvement during World War I was considerably less significant. In early 1915, Asama ran aground while on a mission to intercept German commerce raiders and remained under repair for two years. Meanwhile, Tokiwa took part in the Battle of Tsingtao (1914) and also conducted searches for enemy raiders. Both cruisers undertook training voyages throughout the war and continued these activities after 1918.
Asama maintained her role as a training vessel until she grounded again in 1935, after which she served as a stationary training platform for the remainder of her service life. Tokiwa underwent conversion to a minelayer between 1922 and 1924 but was placed into reserve status in 1927 following an accidental mine explosion that caused significant damage. She was reactivated as a training minelayer by 1940. During the Pacific War (1941–1945), Tokiwa took part in operations including the seizure of the Gilbert Islands in 1941 and the assaults on Rabaul and Kavieng in New Guinea during 1942. After sustaining damage from American air strikes, she returned to Japan for repairs. From 1944 to 1945, Tokiwa laid minefields but suffered damage twice due to mines. Near the war’s conclusion, heavy attacks by US aircraft forced her crew to beach the vessel. She was salvaged in 1947 and subsequently dismantled for scrap. In contrast, Asama survived World War II intact and was scrapped between 1946 and 1947.
Technical Specifications
| Attribute | Details |
|---|---|
| Ship type | Armored cruiser |
| Displacement | Approximately 9,514–9,557 long tons (9,667–9,710 t) |
| Length overall | 442 ft 0 in (134.72 m) |
| Beam | 67 ft 2 in (20.48 m) |
| Draft | 24 ft 3 in – 24 ft 5 in (7.4–7.43 m) |
| Propulsion | Two shafts powered by twin triple-expansion steam engines |
| Power output | 18,000 ihp (13,000 kW) |
| Boilers | Twelve cylindrical Scotch marine boilers |
| Maximum speed | 21 knots (39 km/h; 24 mph) |
| Operational range | 10,000 nautical miles (19,000 km; 12,000 mi) at cruising speed of 10 knots (19 km/h; 12 mph) |
| Crew complement | 676 personnel |
| Armament |
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| Armor protection |
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Background and design
Following the conclusion of the First Sino-Japanese War in 1894–95, the 1896 Naval Expansion Plan was formulated, incorporating four armored cruisers alongside an additional four battleships. Due to Japan's inability to construct these vessels domestically, all had to be commissioned from overseas shipyards. The Imperial Japanese Navy (IJN), upon assessing Russia’s naval construction program, concluded that the battleships initially planned would not adequately counter the Imperial Russian Navy. Financial constraints prevented the acquisition of more battleships, leading to a decision to increase the number of armored cruisers from four to six, as these were more cost-effective. This updated strategy became widely recognized as the "Six-Six Fleet".[1] Funding for these ships was sourced from the £30,000,000 indemnity paid by China after its defeat in the First Sino-Japanese War.[2] Unlike many contemporaneous cruisers designed primarily for commerce raiding or safeguarding colonies and trade routes, these vessels were intended for reconnaissance within the fleet and to participate directly in the battleline.[3]
In June 1896, Sir Andrew Noble, while in Japan, sent a telegram to Armstrong Whitworth authorizing the construction of two stock cruisers. Preliminary design efforts commenced based on an enhanced version of the earlier Chilean cruiser O'Higgins. After several design revisions, the IJN gave final approval on 21 August. The approved design was over 1,000 long tons (1,016 t) larger, possessed greater firepower, and was marginally faster than the Chilean armored cruiser.[4] Although the first ship was laid down in October, formal orders from Japan were not placed until 6 July 1897.[5]
Description
These vessels measured 442 feet 0 inches (134.72 m) in overall length and 408 feet 0 inches (124.36 m) between perpendiculars. Their beam spanned 20.48 meters (67 ft 2 in), while their average draft ranged between 24 feet 3 inches – 24 feet 5 inches (7.40–7.43 m). At normal load, their displacement was between 9,514–9,557 long tons (9,667–9,710 t), increasing to 10,311–10,353 long tons (10,476–10,519 t) at deep load. The ships exhibited metacentric heights of approximately 2 feet 9 inches – 2 feet 11 inches (0.85–0.88 m).[6] Each vessel accommodated a crew complement of 676 officers and enlisted personnel.[7]
Propulsion for the Asama-class consisted of two vertical triple-expansion steam engines with four cylinders each, manufactured by Humphrys, Tennant and Dykes, each connected to a separate propeller shaft.[8] Steam was generated by twelve cylindrical Scotch marine boilers powering these engines rated collectively at 18,000 indicated horsepower (13,000 kW). The ships were designed to reach speeds of 22 knots (41 km/h; 25 mph), a target they surpassed during sea trials by achieving velocities between 22.07–23.1 knots (40.87–42.78 km/h; 25.40–26.58 mph) with power outputs ranging from 19,000–19,040 ihp (14,170–14,200 kW). Their coal storage capacity reached up to 1,390 long tons (1,410 t), enabling a cruising range of approximately 10,000 nautical miles (19,000 km; 12,000 mi) at a speed of 10 knots (19 km/h; 12 mph).[9][7]
Armament
The principal offensive weaponry for every armored cruiser in the "Six-Six Fleet" comprised four eight-inch guns, each with a 45-caliber length, manufactured by Armstrong Whitworth. These were arranged in twin gun turrets positioned both at the front and rear of the superstructure. The turrets, powered electrically, could rotate 130° to either side, while the guns themselves had an elevation range from −5° depression to +30° elevation. Each turret held 65 shells, which were loaded through openings in the turret floor and the ship’s deck, enabling an electric winch within the turret to lift ammunition from the shell room located deep within the hull. Altogether, each gun was supplied with 120 shells. The loading process was manual, allowing a firing rate of approximately 1.2 rounds per minute. These 203-millimeter guns launched 250-pound (113.5 kg) armor-piercing projectiles at a muzzle velocity of 2,500 feet per second (760 m/s), reaching targets up to 13,200 yards (12,100 m) away.
The secondary weapons array included fourteen 40-caliber quick-firing (QF) six-inch guns produced by Elswick Ordnance Company, known as "Pattern Z." Except for four units, these guns were housed within armored casemates on both the main and upper decks; those placed on the upper deck featured additional protection from gun shields. Each gun discharged 100-pound (45.4 kg) armor-piercing shells at a muzzle velocity of 2,300 feet per second (700 m/s). A total of 150 rounds per gun were carried aboard. For defense against torpedo boats at close quarters, the vessels were outfitted with twelve 40-caliber QF 12-pounder 12-cwt guns and eight QF 2.5-pounder Hotchkiss "Yamauchi" guns. The former fired three-inch (76 mm) shells weighing 12.5-pound (5.7 kg) at a muzzle velocity of 2,359 feet per second (719 m/s).
Regarding torpedo armament, the Asama-class cruisers featured five submerged 18-inch (457 mm) torpedo tubes—two installed on each broadside and one positioned above water in the bow. They utilized Type 30 torpedoes equipped with a warhead weighing 100-kilogram (220 lb) and offered three selectable range and speed configurations: 870 yards (800 m) at 27 knots (50 km/h; 31 mph), 1,100 yards (1,000 m) at 23.6 knots (43.7 km/h; 27.2 mph), or 3,300 yards (3,000 m) at 14.2 knots (26.3 km/h; 16.3 mph).
Protection
The armored cruisers of the "Six-Six Fleet," including the Asama class, shared a largely uniform armor layout with only slight variations. Notably, the Asama class utilized Harvey armor. Their waterline belt extended along the entire length of each vessel, with thickness ranging from 7.0 inches (178 mm) amidships to 3.5 inches (89 mm) at both the bow and stern. The belt's most heavily armored section spanned the central part of the ship for approximately 284 feet 2 inches (86.62 m). This belt measured 7 feet 0 inches (2.13 m) in height, with roughly 4 feet 11 inches to 5 feet 0 inches (1.51 to 1.52 m) submerged beneath the waterline. Above this, an upper belt strake of armor, 5.0 inches (127 mm) thick, stretched from the waterline belt’s top edge up to the main deck, covering a length of 214 feet 8 inches (65.42 m) between the forward and aft barbette positions. The Asama-class also featured a single transverse 5-inch armored bulkhead sealing off the forward end of their central armored citadel.
The barbettes, gun turrets, and frontal casemate faces were uniformly protected by 6 inches of armor, while the casemates’ sides and rears had armor thicknesses of 51 millimeters (2.0 in). The above-water torpedo tube located at the bow was shielded by a 6-inch armored patch measuring 23 by 9 feet (7.0 by 2.7 m). The conning tower boasted armor plating up to 356 millimeters (14.0 in) thick. In addition to their Harvey armor, the Asama ships were distinguished among their fleet counterparts by having an armored deck thickness of 51 millimeters (2.0 in). Structurally, these vessels incorporated 32 watertight compartments within their double bottom and an extra 131 compartments situated between the bottom and upper deck.
Ships
| Ship | Builder | Laid down | Launched | Completed |
|---|---|---|---|---|
| Asama | Armstrong Whitworth, Elswick | 20 October 1896 | 22 March 1898 | 8 February 1899 |
| Tokiwa | 6 January 1897 | 6 July 1898 | 18 April 1899 |
Service
Prior to the outbreak of the Russo-Japanese War in 1904, Tokiwa played a support role for Japanese forces during the Boxer Rebellion in China, while Asama took part in the 1902 Coronation Review commemorating King Edward VII.
Russo-Japanese War
At the onset of hostilities during the Russo-Japanese War, both cruisers were assigned to the 2nd Division of the 2nd Fleet. However, Asama was temporarily attached to Rear Admiral Uryū Sotokichi’s 4th Division for operations near Seoul, Korea. Just before conflict erupted, Asama escorted Japanese troop convoys to Chemulpo, Seoul’s port on Korea’s west coast, where it contributed to sinking two Russian warships stationed there on day one of the war. On that same initial day, Tokiwa participated in the Battle of Port Arthur, when Vice Admiral Tōgō Heihachirō led an assault by the Combined Fleet against Russian Pacific Squadron vessels anchored outside Lüshunkou District. Although Tōgō had anticipated his destroyers' prior surprise night attack would severely disrupt Russian defenses, the enemy forces had recovered sufficiently to mount a prepared defense during his follow-up offensive.
In early March, Tokiwa was shifted to the 3rd Division with Asama joining shortly thereafter. Both cruisers took part in the engagement on 13 April when Tōgō successfully drew out two Russian battleships from their Pacific Squadron. During this encounter, they engaged Russian cruisers that preceded these battleships before withdrawing toward Tōgō’s battleship formation. Upon spotting five battleships from Japan’s 1st Division, Russian forces retreated toward Port Arthur; however, one battleship, Russian battleship Petropavlovsk, struck a minefield laid by Japanese forces overnight and sank rapidly after a magazine explosion.
Following this action, Tokiwa rejoined the 2nd Division tasked with containing Russian armored cruisers based at Vladivostok. This containment effort remained unsuccessful until 13 August when those Russian ships attempted to link up with vessels escaping Port Arthur. Unaware that Tōgō had already defeated Port Arthur's breakout fleet during the Battle of the Yellow Sea on 10 August, the Vladivostok squadron was intercepted off Ulsan by the Japanese 2nd Division. Early in this battle, damage to steering impaired the Russian cruiser Russian cruiser Rurik, prompting repeated efforts by Russian ships to shield her from concentrated Japanese fire; ultimately she was abandoned. Commander Kamimura left Rurik under care of reinforcements while pursuing remaining Russian cruisers but ceased pursuit prematurely after receiving inaccurate reports about his flagship's ammunition status. Throughout this battle, Tokiwa sustained only three wounded personnel.
Meanwhile, Asama maintained blockade duties off Port Arthur and played a limited role in the Battle of the Yellow Sea. Being engaged in coaling operations when the Pacific Squadron sortied, she required time to intercept and only engaged enemy ships during roughly the final hour of combat. Afterward, both sister ships underwent refits before being assigned different tasks such as escorting troop convoys to northern Korea and blockading the Tsugaru Strait until mid-1905 when Russian Baltic Fleet vessels approached Japan’s waters.
Battle of Tsushima
On the morning of 27 May 1905, the Russian 2nd and 3rd Pacific Squadrons were sighted, prompting Tōgō to command his fleet to set sail. Asama and Tokiwa were positioned within the 2nd Division in preparation for the impending engagement. Kamimura's vessels confirmed the initial sighting later that day before joining forces with Tōgō's battleships. Alongside the majority of Japan’s battleships, this division commenced firing at 14:10 on the Russian battleship Oslyabya. Shortly thereafter, Asama sustained damage from a shell that disabled her steering, forcing her to drop out of formation temporarily. At approximately 15:35, the Russian battleship Knyaz Suvorov suddenly emerged from the fog at close range. Kamimura’s ships engaged her for five minutes before she vanished back into the mist. By 15:50, Asama had rejoined the division; however, subsequent hits caused severe flooding that once again compelled her to leave formation around 20 minutes later. She managed to catch up by 17:05. Soon after, Kamimura led a futile chase of several Russian cruisers starting around 17:30 but abandoned the pursuit by 18:03. Approximately thirty minutes later, his forces encountered the Russian battleline, maintaining long-range fire when feasible and ceasing engagement at 19:30.
The following morning, surviving Russian vessels were located by Japanese forces who opened fire while remaining out of effective range of return fire. Rear Admiral Nikolai Nebogatov, unable to respond or close distance, opted to surrender his fleet. During this clash, Asama endured roughly a dozen shell impacts resulting in eleven fatalities and thirteen injuries among her crew. Conversely, Tokiwa was hit by eight shells causing minor damage but suffered one fatality and fourteen wounded personnel. Following the battle, this division provided cover for amphibious landings in northeastern Korea during July and August before the conclusion of hostilities.
Subsequent service
Between 1910–11 and in 1914, Asama functioned as a training vessel, conducting voyages with naval cadets to destinations including North America, Central America, and Hawaii. After World War I began in August 1914, she was tasked with hunting Vice Admiral Maximilian von Spee's German East Asia Squadron across the South Sea Islands. In late October, she was ordered to blockade a German gunboat stationed in Honolulu, Hawaii. Following that vessel’s internment in early November, Asama joined the American Expeditionary Squadron—the Japanese segment of a combined Anglo-Japanese force—operating off Mexico's coastline to safeguard shipping against German commerce raiders over several months.
In early 1915, while entering Puerto San Bartolomé in Baja California, Asama struck an uncharted rock and sustained significant damage. Efforts to refloat and render her partially seaworthy extended over months. Temporary repairs were conducted at the British naval base in Esquimalt, British Columbia, before she returned to Japan in December; permanent restoration was not finalized until March 1917. Later that year, she was assigned to the Training Squadron and undertook another cadet training cruise in 1918.
Meanwhile, Tokiwa supported Japanese forces during the Battle of Tsingtao prior to returning to Sasebo in October 1914. She joined the Training Squadron in 1916 ahead of a training cruise undertaken the following year. In October 1917, she was deployed to Hawaii to protect maritime traffic from German raiders and facilitate redeployment of US Navy units to the Atlantic theater. Between 1919 and 1920, Tokiwa completed two additional cruises before undergoing conversion into a minelayer from 1922 to 1924. To accommodate between 200 and 300 naval mines, her aft 8-inch gun turret was removed along with six main deck 6-inch guns; light armament was reduced to two 12-pounder guns while two 8 cm/40 3rd Year Type anti-aircraft (AA) guns were installed. These AA guns had a maximum elevation of +75 degrees and could fire a three-inch projectile weighing approximately 5.67 kg (12.5 lb) at a muzzle velocity near 680 m/s (2,200 ft/s), reaching an altitude up to 7,200 meters (23,600 ft).
In 1921, Asama conducted another training cruise prior to receiving armament modifications in 1922. All six main deck six-inch guns and four twelve-pounder guns were removed with their casemates sealed off; additionally, all QF 2.5-pounder guns were taken off and a single 8 cm/40 AA gun was added. Post-refit, she resumed training voyages typically every two years until grounding incidents in 1935 caused severe hull damage. Due to this damage, the Imperial Japanese Navy converted her into a stationary training ship by 1938.
In an accident during mine disarming operations in 1927, Tokiwa’s stern suffered extensive damage when one mine detonated followed by several others exploding sequentially; this incident resulted in thirty-five deaths and sixty-five injuries among crew members. After repairs, she was placed into reserve status but resumed patrolling Chinese waters following Japan’s invasion of Manchuria in 1931. Between 1937 and 1938, she underwent modernization including installation of eight Kampon water-tube boilers which reduced her top speed to 16 knots (30 km/h; 18 mph) and removal of remaining torpedo tubes; these changes increased her mine capacity to approximately five hundred. In 1940, further conversion transformed her into a dedicated training minelayer reducing capacity back down to between two hundred and three hundred mines. This refit involved removing her forward eight-inch turret along with four amidships six-inch guns as well as one of her two 8 cm/40 AA guns. Her anti-aircraft arsenal was significantly enhanced with addition of two single 40 millimetres (1.6 in) guns plus twenty license-built twin-mounted 25-millimeter Type 96 light AA weapons.
The Type 96 light AA gun served as Japan’s standard light anti-aircraft armament during World War II but suffered from notable design flaws that limited its effectiveness: slow traverse and elevation speeds on twin/triple mounts; inadequate sights for fast-moving targets; excessive vibration; small magazine capacity; and significant muzzle blast. Although it had a maximum range near 7,500 metres (24,600 ft), its effective engagement distance was only about 1,500–3,000 metres (4,900–9,800 ft).
The Pacific War
Shortly following the attack on Pearl Harbor, Tokiwa along with other minelayers from the 19th Division of the 4th Fleet escorted two troop transports that carried occupation forces to the Gilbert Islands.[10] In January 1942, she took part in Operation R, which involved the seizure of Rabaul and Kavieng, before returning to Kwajalein Atoll. The vessel sustained damage from American carrier-based aircraft in February 1942, necessitating a return to Japan for repairs. On 14 July, Tokiwa arrived back at Truk and subsequently reoccupied Makin Atoll in August following the Makin Raid.[11]
In 1943, the ship returned to home waters and began deploying defensive minefields by 1944. She incurred moderate damage from a mine in April 1945 and struck another American mine two months later. By this stage, her armament had been enhanced to include approximately ten single-mounted 25 mm Type 96 anti-aircraft guns and a complement of 80 depth charges. Additionally, Tokiwa was equipped with Type 3, Mark 1, Model 3 and Type 2, Mark 2, Model 1 air search radar systems.[12] While stationed in northern Japan just days before the war's end, she suffered severe damage from American carrier aircraft attacks and was deliberately beached by her crew to prevent sinking.[11]
Reclassified as a training vessel in 1942, Asama transitioned into a gunnery training ship later that year. During the course of the war, she was disarmed except for retaining several 8 cm/40 3rd Year Type anti-aircraft guns.[13] Both Asama and Tokiwa survived the conflict but were removed from the naval register in November 1945. Asama was dismantled between 1946 and 1947, whereas Tokiwa was refloated in 1947 and scrapped within that same year.[11][14]
External links
- ↑ Evans & Peattie, pp. 57–62
- ↑ Brook 1999, p. 125
- ↑ Milanovich, p. 72
- ↑ Brook 1999, pp. 107–09
- ↑ Milanovich, p. 73
- ↑ Milanovich, pp. 74, 80
- ↑ 7.0 7.1 Jentschura, Jung & Mickel, p. 72
- ↑ Milanovich, p. 81
- ↑ Brook 1999, p. 109
- ↑ Rohwer, p. 123
- ↑ 11.0 11.1 11.2 Hacket & Kingsepp
- ↑ Fukui, p. 13
- ↑ Fukui, p. 53
- ↑ Lacroix & Wells, p. 659