Japanese aircraft carrier Kaga

Kaga after her modernization. Note her downward facing funnel
Career (Japan)
Name:	Kaga
Namesake:	Kaga Province
Laid down:	19 July 1920
Launched:	17 November 1921
Completed:	31 March 1928
Commissioned:	30 November 1929
Reclassified:	21 November 1923 as an aircraft carrier
Refit:	20 October 1933–25 June 1935
Struck:	10 August 1942
Fate:	Sunk by US air attack at the Battle of Midway on 4 June 1942
General characteristics (after 1935 modernization)
Type:	aircraft carrier
Displacement:	38,200 long tons (38,800 t) (standard)
Length:	247.65 m (812 ft 6 in)
Beam:	32.5 m (106 ft 8 in)
Draught:	9.48 m (31 ft 1 in)
Propulsion:	4-shaft Kampon geared turbines 8 Kampon Type B boilers 127,400 shp (95,000 kW)
Speed:	28.34 knots (32.61 mph; 52.49 km/h)
Endurance:	10,000 nmi (18,520 km) at 15 knots (28 km/h)
Complement:	1,708 (after reconstruction); 2,016 (total)
Armament:	10 × 1 - 200 mm (7.9 in) guns, 8 × 2 - 127 mm (5.0 in) guns, 11 × 2 - 25 mm (0.98 in) AA guns
Armour:	Belt: 152 mm (6.0 in) Deck: 38 mm (1.5 in)
Aircraft carried:	90 (total); 72 (+18) 18 Zeros, 37 Vals, 37 Kates (Dec. 1941)

Kaga (Japanese: 加賀, formerly Kaga Province, in present-day Ishikawa Prefecture) was an aircraft carrier of the Imperial Japanese Navy, originally intended as a Tosa-class battleship. She supported Japanese troops during the Shanghai Incident of 1932 and participated in the Second Sino-Japanese War in the late 1930s. She took part in the Pearl Harbor raid, several battles in the Southwest Pacific in January and February 1942, and was sunk at the Battle of Midway on 4 June 1942.

Design

Kaga was laid down as a Tosa-class battleship, and was launched on 17 November 1921 at the Kawasaki Heavy Industries shipyard in Kobe. On 5 February 1922 both Tosa class ships were canceled and designated for scrapping under the terms of the Washington Naval Treaty.

The Treaty authorized conversion of two battleship or battlecruiser hulls into aircraft carriers of up to 33,000 tons standard displacement. The incomplete battlecruisers Amagi and Akagi were initially selected, but the Great Kantō Earthquake of 1923 damaged Amagi's hull beyond economic repair. Kaga was therefore selected as her replacement. Kaga's conversion to an aircraft carrier was ordered on 13 December 1923, but nothing was done until 1925 as new plans had to be drafted and the Yokosuka Naval Arsenal's damage from the earthquake had to be repaired. She was officially commissioned on 31 March 1928, but this really only signified the beginning of sea trials. She joined the Combined Fleet (Rengo kantai) on 30 November 1929.^[1]

General characteristics

Kaga was completed at a length of 238.5 m (782 ft) overall. She had a beam of 31.67 m (103.9 ft) and at full load a draft of 7.92 m (26.0 ft). She displaced 26,900 long tons (27,300 t) at a standard load, and 33,693 long tons (34,230 t) at full load, nearly 6,000 long tons (6,100 t) less than her designed displacement as a battleship.^[2]

Flight deck arrangements

Kaga, like Akagi, was completed with three superimposed flight decks, the only carriers ever to be designed so. The British carriers converted from "large light cruisers", HMS Glorious, HMS Courageous, and HMS Furious each had two flight decks, but there is no evidence that the Japanese copied the British model. It is more likely that it was a case of convergent evolution as a means to launch as many aircraft as quickly as possible. Kaga's main flight deck was 171.2 metres (562 ft) long, her middle flight deck began right in front of the bridge and was only about 15 metres (49 ft) long and her lower flight deck was approximately 55 metres (180 ft) long. The utility of her middle flight deck had to be questionable as it was so short that only lightly loaded aircraft had any chance of using it at all, even in an era where the aircraft were much lighter and smaller than they were during the Second World War. At any rate the ever-increasing growth in aircraft performance, size and weight meant that even the bottom flight deck was no longer able to accommodate the take-off roll required for the new generations of aircraft being fielded and it was plated over when the ship was modernized in the mid-1930s.^[3]

As completed, the ship had two main hangar decks and a third auxiliary hangar with a total capacity of 60 aircraft. The hangars opened onto the middle and lower flight decks to allow aircraft to take off directly from the hangars, while landing operations were in progress on the main flight deck above. No catapults were fitted.^[4] Her forward aircraft lift was offset to starboard and 10.67 by 15.85 metres (35.0 ft × 52.0 ft) in size. Her aft lift was on the centerline and 12.8 by 9.15 metres (42 ft × 30 ft). Her arresting gear was a French transverse system used on their aircraft carrier Béarn known as the Model Fju (Fju shiki) in Japanese service.^[5]

Armament

Kaga was armed with ten 20 cm (7.9 in)/50 3rd Year Type guns; one twin Model B turret on each side of the middle flight deck and six in Model A₁casemates aft. They fired 110-kilogram (240 lb) projectiles at a rate of 3–6 rounds per minute with a muzzle velocity of 870 m/s (2,900 ft/s); at 25°, this provided a maximum range between 22,600–24,000 m (24,700–26,200 yd). The Model B turrets were nominally capable of 70° elevation to provide additional anti-aircraft fire, but in practice the maximum elevation was only 55°. The slow rate of fire and the fixed 5° loading angle minimized any real anti-aircraft capability.^[6] This heavy gun armament was provided in case she was surprised by enemy cruisers and forced to give battle. While superficially logical this ignored her large and vulnerable flight deck, hangars, etc., that made her more of a target in any surface action than a fighting warship. The Americans did much the same with the provision of four twin 8-inch (203 mm) gun turrets on their Lexington-class carriers. She was given an anti-aircraft armament of six twin 12 cm (4.7 in) 45-caliber 10th Year Type Model A₂ gun mounts fitted on sponsons below the level of the funnels, where they could not fire across the flight deck, three mounts per side.^[7] These guns fired 20.3-kilogram (45 lb) projectiles at a muzzle velocity of 825–830 m/s (2,710–2,720 ft/s); at 45° this provided a maximum range of 16,000 m (17,000 yd), and they had a maximum ceiling of 10,000 m (11,000 yd) at 75° elevation. Their effective rate of fire was 6–8 rounds per minute.^[8] She had two Type 89 directors to control her 20 cm guns and two Type 91 manually-powered anti-aircraft directors (Kōshaki) to control her 12 cm guns.^[9]

Armor

Kaga fitting out in 1928. Note the long funnel below the flight deck and the three 8-inch guns in casemates

Kaga's waterline armored belt was reduced from 280 to 152 mm (11 to 6.0 in) and the upper part of her torpedo bulge was given 127 mm (5.0 in) of armor. Her deck armor was also reduced from 102 to 38 mm (4.0 to 1.5 in).^[5]

Propulsion

When Kaga was being designed the problem of how to deal with exhaust gases in carrier operations had not been resolved. The swivelling funnels of the Hōshō had not proved successful and wind-tunnel testing had not provided an answer either. So Akagi and Kaga were each given different solutions to evaluate in real-world conditions. Kaga's funnel gases were collected in a pair of long horizontal ducts which discharged at the rear of each side of the flight deck although a number of prominent naval architects predicted they would not keep the hot gases away from the flight deck. They proved to be correct, not least because Kaga was slower than the Akagi which allowed the gases to rise and interfere with landing operations. Another drawback was that the heat of the gases made the crew's quarters located on the side of the ship by the funnels almost uninhabitable.^[5]

Kaga was completed with four Kawasaki Brown-Curtis geared turbines with a total of 91,000 shp (68,000 kW) on four shafts. As a battleship her expected speed was 26.5 knots (30.5 mph; 49.1 km/h), but her reduction in weight from 39,900 to 33,693 long tons (40,500 to 34,200 t) allowed to her speed to increase to 27.5 knots (31.6 mph; 50.9 km/h) on trials on 15 September 1928. She had twelve Type B (Ro) Kampon boilers with a working pressure of 20 kg/cm², although only eight were oil-fired. The other four used a mix of oil and coal. She carried 8,000 long tons (8,100 t) of fuel oil and 1,700 long tons (1,700 t) of coal to give her a range of 8,000 nmi (14,820 km) at 14 knots (26 km/h).^[5]

Early history

Kaga departed for Chinese waters on 29 January 1932 to support Imperial Japanese Army troops during the Shanghai Incident and she returned to Japan on 22 March. She was reduced to second class reserve status on 20 October 1933 at the beginning of her reconstruction, even though the official start date was 25 June 1934.^[10]

Reconstruction

In service, she was judged inferior to Akagi because of her slower speed, smaller flight deck and problematic funnel arrangement. In 1934, Kaga therefore commenced a second major reconstruction. The flight deck and hangars were extended to the bow, increasing the flight deck length to 248.55 metres (815.5 ft) and raising aircraft capacity to 90 (72 operational and 18 in storage). A third elevator forward, 11.5 by 12 metres (38 ft × 39 ft) in size, serviced the extended hangars. Bomb and torpedo elevators were modified to deliver their munitions directly to the flight deck. Her arrester gear was replaced by a Japanese-designed Type 1 system. A small starboard island superstructure was also installed.^[4]

Her power plant was completely replaced as were her propellers. New Kampon multi-stage geared turbines were fitted that increased power from 91,000 to 127,400 shp (68,000 to 95,000 kW) during trials. Each had a high-pressure, a low-pressure, and a cruising turbine coupled to a single shaft. Her boilers were replaced by eight oil-burning, improved models of the Kampon Type B (Ro) with a working pressure of 22 kg/cm² (2,157 kPa; 313 psi) at a temperature of 300 °C (572 °F). The hull was lengthened by 10.3 metres (34 ft) at the stern to reduce drag and she was given another torpedo bulge above the side armor abreast the upper part of the existing bulge to increase her beam and lower her center of gravity as a result of lessons learned from the Tomozuru Incident in early 1934. This raised her standard displacement by over 11,000 tons (from 26,900 to 38,200 long tons (27,300 to 38,800 t). Unfortunately the extra power and the extra displacement roughly offset each other and her speed increased by less than a knot (from 27.5 to 28.34 knots (31.6 to 32.6 mph; 50.9 to 52.5 km/h) on trials. Her bunkerage was increased to 7,500 long tons (7,600 t) of fuel oil which increased her endurance to 10,000 nmi (18,520 km) at 16 knots (30 km/h). The lengthy funnel ducting was replaced by a single downturned starboard funnel modeled on that used by the Akagi with a water-cooling system for the exhaust gasses and a blind cover designed to allow the exhaust gasses to escape if the ship developed a severe list and the mouth of the funnel touched the sea. The space freed up by the removal of the funnel ducts was divided into two decks and converted into living quarters for the expanded air group.^[11]

The two twin turrets on the middle flight deck were removed and four new 20 cm/50 3rd Year Type No. 1 guns in casemates were added forward. Her 12 cm anti-aircraft guns were replaced by eight twin 12.7 cm (5.0 in)/40 Type 89 gun mounts. The guns fired 23.45-kilogram (51.7 lb) projectiles at a rate between 8–14 rounds per minute at a muzzle velocity between 700–725 m/s (2,300–2,400 ft/s); at 45°, this provided a maximum range of 14,800 m (16,200 yd), and a maximum ceiling of 9,400 m (10,300 yd).^[12] Their sponsons were raised one deck to allow them some measure of cross-deck fire. Eleven twin 25 mm (0.98 in) Type 96 gun mounts were added, also on sponsons. They fired .25-kilogram (0.55 lb) projectiles at a muzzle velocity of 900 m/s (3,000 ft/s); at 50°, this provided a maximum range of 7,500 m (8,200 yd), and an effective ceiling of 5,500 m (6,000 yd). The maximum effective rate of fire was only between 110–120 rounds per minute due to the frequent need to change the 15-round magazines.^[13] Six 6.5 mm Type 11 machine guns were also carried.^[11] Six Type 95 directors were fitted to control the new 25 mm guns, but Kaga retained her outdated Type 91 anti-aircraft directors.^[14]

History before World War II

Kaga returned to service in 1935. During the late 1930s she supported operations in China during the early years of the Second Sino-Japanese War. She was refitted beginning in 15 December 1938 and her arrester gear was replaced by a Type 3 system and her bridge was modernized. She was completely overhauled from 15 November 1939 to 15 November 1940 before returning to active service. She was assigned to the First Carrier Division, with Akagi, when the First Air Fleet was formed on 10 April 1941.^[10]

Service in World War Two

Together with Akagi she formed the First Carrier Division of the Kido Butai for the attack on Pearl Harbor. On 7 December 1941 she launched two strikes against Oahu. In her first strike, 26 Nakajima B5N "Kate" torpedo bombers targeted Arizona, Vestal, Tennessee, West Virginia, Oklahoma, and Nevada, and 9 Mitsubishi A6M "Zero" fighters attacked the airbase at Hickam Field. In her second strike, 23 Aichi D3A "Val" dive bombers targeted Nevada, Maryland, and West Virginia.^[15]

In January 1942, together with the rest of the First and Fifth Carrier Divisions, Kaga supported the invasion of Rabaul in the Bismarck Islands. Kaga provided 27 B5N "Kates" and 9 A6M "Zeros" for the initial airstrike on Rabaul on 20 January 1942, during which one B5N was shot down by anti-aircraft fire. The First Carrier Division attacked Allied positions at near-by Kavieng the following day, of which Kaga contributed 9 A6M "Zeros" and 16 D3A "Vals". On the 22nd Kaga's "Vals" and "Zeros" again attacked Rabaul and two "Vals" had to make emergency landings, but the crews were rescued. Kaga returned to Truk on 25 January.^[16]

On 9 February she hit a reef at Palau after she had sortied against American forces attacking the Marshall Islands on 1 February before being recalled. After temporary repairs, she continued to the Timor Sea, where on 19 February 1942 she, with the other carriers of the First and Second Carrier Divisions, launched air strikes against Darwin, Australia. Kaga contributed 27 "Kates", 18 "Vals, and 9 "Zeros" to the attack which caught the defenders by surprise. Eight ships were sunk, including USS Peary, and fourteen more were damaged for the loss of one of Kaga's "Kates". In March 1942, Kaga covered the invasion of Java although her only contribution appears to have been aircraft for the 5 March 1942 airstrike on Tjilatjap. This was very successful, sinking eight ships in the harbor there, but specific details for Kaga's aircraft are unknown. Kaga was unable to participate in the Indian Ocean raid in April because of the damage she had received in February. Instead, she sailed for Sasebo on 15 March for repairs, entering drydock on 27 March.^[17]

Battle of Midway

In May 1942, Kaga sailed on her final mission. Her aircraft complement was 30 "Zeros," 23 "Vals," and 30 "Kates." ^[18] At dawn on 4 June 1942 Kaga launched an air strike against Midway Island that consisted of eighteen "Vals" escorted by nine "Zeros"; one each of the "Vals" and "Zeros" was shot-down by AA fire and another four "Vals" damaged. One "Kate" was also launched to help search for the Americans. She also put up two "Zeros" on combat air patrol.^[19] Another five "Zeros" had reinforced her CAP at 07:00 and all seven fighters helped to defend the Kido Butai from the first attackers from Midway Island at 0710.^[20] At 07:15 Admiral Nagumo ordered the "Kates" still on Kaga and Akagi rearmed with bombs for another attack on Midway itself. This process was limited by the number of ordnance carts used to handle the bombs and torpedoes and the limited number of ordnance elevators. This meant that the torpedoes could not be struck below until after all the bombs were moved up from their magazine, assembled and mounted on the aircraft. This process normally took about an hour and a half; more time would be required to bring the aircraft up to the flight deck, warm up and launch the strike group. Around 07:40 he reversed his order when he received the message that the Americans had been spotted.^[21] At 0730 Kaga recovered three of her CAP.^[22]

Kaga's four remaining CAP fighters were in the process of landing when sixteen Marine SBD Dauntless dive-bombers of VMSB-241 attacked Hiryu around 07:55 without result.^[23] Five Zeros were launched at 08:15 and three intercepted a dozen B-17 Flying Fortress attempting to bomb the three other carriers from 20,000 feet (6,100 m), but only limited damage was inflicted on the heavy bombers, although their attacks all missed. Five "Vals" also joined the CAP around this time. Another trio of "Zeros" was launched at 08:30. Kaga began landing her strike force aboard around 08:35 and was finished by 08:50, one "Zero" pilot dying after crash-landing his aircraft.^[24] The five Zeros launched at 0815 were recovered aboard at 09:10 and replaced by six more "Zeros" launched at 09:20. They intercepted the TBD Devastator torpedo-bombers of VT-8 at 09:22 and shot down all fifteen, leaving only a single survivor treading water. Shortly afterwards fourteen Devastators from VT-6 were spotted. They tried to sandwich Kaga, but the CAP, reinforced by another another six "Zeros" launched by Kaga at 10:00, shot down all but four of the Devastators.^[25]

At 10:22, SBD Dauntless dive-bombers from USS Enterprise's VS-6 and VB-6 hit her with one 1,000-pound (450 kg) bomb and at least three 500-pound (230 kg) bombs, although she shot down one dive-bomber before it could drop its bombs. The first landed near her rear elevator and set the berthing compartments on fire, the next bomb hit the forward elevator and penetrated the upper hangar which set off explosions and fires among the armed and fueled planes on her hangar deck. Captain Okada was killed by the third bomb that hit the bridge and the 1000 pound hit amidships and penetrated the flight deck to explode on the upper hangar. The explosions had ruptured her avgas lines, damaged both her port and starboard fire mains and her emergency generator powering her fire pumps as well as knocking out her carbon dioxide fire suppression system.^[26] Fueled by the avgas pouring onto the hangar deck the fires detonated the bombs and torpedoes strewn across the hangar deck in a series of multiple fuel-air explosions that literally blew out the hangar sides.^[27]

At about 14:05 the submarine USS Nautilus hit Kaga with a torpedo, but it was a dud and did not explode.^[28] Kaga's crew were taken off by the destroyers Hagikaze and Maikaze, and around 19:25 she was scuttled by two torpedoes and sank at position 30°20′N 179°17′W / 30.333°N 179.283°W / 30.333; -179.283.^[29]

In 1999, the Nauticos company discovered wreckage that has been identified as coming from Kaga.^[30]

Commanding officers

• Chief Equipping Officer - Capt. Seizaburo Kobayashi - 10 March 1927 - 1 *December 1927
• Chief Equipping Officer - Capt. Giichiro Kawamura - 1 December 1927 - 1 March 1928
• Capt. Giichiro Kawamura - 1 March 1928 - 1 December 1930
• Capt. Sekizo Uno - 1 December 1930 - 1 December 1931
• Capt. Jiro Onishi - 1 December 1931 - 15 November 1932
• Capt. Shunichi Okada - 15 November 1932 - 28 November 1932
• Capt. Goro Hara - 28 November 1932 - 14 February 1933
• Capt. Sonosuke Kobayashi - 14 February 1933 - 15 November 1933
• Capt. Eijiro Kondo - 15 November 1933 - 15 November 1934
• Capt. Teizo Mitsunami - 15 November 1934 - 1 December 1936
• Capt. Ayao Inagaki - 1 December 1936 - 1 December 1937
• Capt. Katsuo Abe - 1 December 1937 - 25 April 1938
• Capt. / RADM Ichiro Ono - 25 April 1938 - 15 December 1938 (Promoted to *Rear Admiral on 15 November 1938.)
• Capt. Setsuzo Yoshitomi - 15 December 1938 - 15 November 1939
• Capt. Kyuji Kubo - 15 November 1939 - 15 October 1940
• Capt. Sadayoshi Yamada - 15 October 1940 - 15 September 1941
• Capt. / RADM*Jisaku Okada - 15 September 1941 - 4 June 1942 (KIA)

Notes

References

• Lengerer, Hans (1982). "Akagi & Kaga". Warship (London: Conway Maritime Press) VI (22-4): 127–39, 170-7, 305-10. ISBN 0-87021-981-2. 
• Parshall, Jonathan; Tully, Anthony (2005). Shattered Sword: The Untold Story of the Battle of Midway. Dulles, Virginia: Potomac Books. ISBN 1-57488-923-0. 

External links

Wikimedia Commons has media related to: Kaga

• IJN Kaga: Tabular Record of Movement, Combinedfleet.com
• Kaga, World War II Database