Japanese aircraft carrier Shinano
 Shinano underway during her sea trials in Tokyo Bay |
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| Career (Japan) |  |
|---|---|
| Name: | Shinano |
| Namesake: | Shinano Province |
| Laid down: | 4 May 1940 |
| Launched: | 5 October 1944 |
| Commissioned: | 19 November 1944 |
| Fate: | Sunk by the submarine USS Archer-Fish, 29 November 1944 |
| General characteristics | |
| Class and type: | Converted Yamato-class battleship |
| Type: | Aircraft carrier |
| Displacement: | 62,000 long tons (63,000 t) (standard) 72,000 long tons (73,000 t) (loaded)[1] |
| Length: | 266 m (872 ft 8 in)[1] |
| Beam: | 36.3 m (119 ft 1 in) waterline 40 m (131 ft 3 in) flight deck[1] |
| Draft: | 10.8 m (35 ft 5 in)[1] |
| Installed power: | 153,000 shp (114,000 kW) |
| Propulsion: | 4 × geared steam turbines[1] 12 × Kampon oil-fired boilers[1] 4 × shafts[1] |
| Speed: | 27 kn (50 km/h; 31 mph)[1] |
| Range: | 10,000 nmi (19,000 km; 12,000 mi) at 27 kn (50 km/h; 31 mph)[1] |
| Complement: | 2,400[2] |
| Armament: | 16 × 127 mm (5.0 in) dual purpose guns[2] 145 × 25 mm (0.98 in) anti-aircraft guns[2] 12 × 28-barreled 127 mm (5.0 in) anti-aircraft rocket launchers[2] |
| Armor: |
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| Aircraft carried: | 47 (capable of storing 139)[1] |
Shinano (Japanese:信濃), named after the ancient Shinano Province, was an aircraft carrier of the Imperial Japanese Navy during World War II. Initially laid down as the third of the Yamato-class battleships, Shinano's partially complete hull was converted to an aircraft carrier in 1942, midway through construction. Over the next two years, Shinano was heavily modified to act as a large support carrier. When completed, she had a full-load displacement of 72,000 long tons (73,000 t), the largest aircraft carrier ever built at the time.
Commissioned in November 1944, Shinano was to transfer from the Yokosuka Naval Shipyard to Kure Naval Base to complete her outfitting. While en route, Shinano was sunk by the American submarine USS Archer-Fish 10 days after her commissioning — the result of severe design flaws, crew inexperience and poor damage control. To date, she is the largest warship to be sunk by a submarine.
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Design and construction
Shinano was initially designed as the third Yamato-class battleship. Her keel was laid down in June 1940 at the Yokosuka Naval Dockyard[1]. Named after the ancient Shinano Province, the vessel would have been one of the three largest battleships ever constructed[1]. In mid-1941, construction on Shinano's hull was temporarily suspended, so as to allow personnel and equipment to be utilized for other naval projects in response to approaching hostilities[3]. Had she been completed as a battleship, her armament and armor would have been nearly identical to that of Yamato and Musashi[1].
Following Japan's disastrous losses at the Battle of Midway — in which four of Japan's six fleet carriers were lost — the decision was made to convert Shinano's unfinished hull to an aircraft carrier[3]. The conversion began in June 1942[4]. The conversion process placed a heavy emphasis on flight-deck armor, similar to the design of the British Illustrious-class aircraft carriers. The flight deck was designed to withstand 454 kg (1,000 lb) bombs, the largest in the arsenal of the United States Navy that could be carried by dive bombers[1]. Shinano was primarily designed as a support carrier, with extensive facilities for aircraft repair and refitting[3]. Shinano herself was intended to have a small fighter complement for defensive purposes, but was not intended to act as a fleet carrier despite her size[2][3]. Shinano was officially launched 5 October 1944, with Captain Toshio Abe in overall command of the vessel. With a full-load displacement of 72,000 long tons (73,000 t)[2], Shinano was the largest aircraft carrier ever built — a rank she would hold until USS Forrestal, with a displacement of 80,000 long tons (81,000 t), was launched in 1954[5].
The ship's very existence was kept a closely-guarded secret. A tall fence was erected on three sides of the graving dock, and those working on the conversion were confined to the yard compound. Serious punishment — up to and including death — awaited anyone who breathed a word about Japan's new carrier. As a result, Shinano was the only major warship built in the 20th century never to have been officially photographed during its construction.[6]
Armament
Shinano's armament differed radically from that of Japan's other aircraft carriers[3]. Shinano's primary defensive armament took the form of 16 127 mm (5.0 in) dual purpose guns[2]. Her anti-aircraft armament was also significant: 125 25 mm (0.98 in) anti-aircraft guns[2], and 336 127 mm (5.0 in) anti-aircraft rocket launchers in 12 28-barrel turrets[1]. Shinano was also built to contain a maximum of 120 aircraft within her 265 m (869 ft) hull[1].
Commissioning and sinking
On 19 November 1944, Shinano was formally commissioned at Yokosuka, having spent the previous two weeks fitting out and performing minor trials[4]. As a result of growing worry for her safety, due to a U.S. bomber fly-over, Japanese Naval Command ordered Shinano to Kure, where the remainder of her fitting-out would take place[4]. Naval Command wanted Shinano moved to Kure no later than 28 November. However, her commanding officer, Captain Toshio Abe, asked for a delay in the sailing date. The majority of her watertight compartment doors had yet to be installed[2], and the ship had not been tested for watertightness. He also wanted more time to train his new crew[6].
Abe's request was denied, and Shinano departed as scheduled on 28 November, escorted by three destroyers. Abe commanded a crew of 2,176 officers and men. Also on board were 300 shipyard workers and 40 civilian employees[1][6]. She also carried six Shinyo suicide boats, and 50 Ohka suicide rockets[4]. Her orders were to go to Kure, where she would complete her fitting-out and commence in the Inland Sea. Shinano was to take the Ohkas east for "the relief of the Philippines"[7]. Abe was due to be promoted to rear admiral once Shinano completed her fitting-out, and take command of a fleet of attack carriers being built up in the east[6]. Although Shinano was to act as a support carrier, she was also assigned her own air group, commanded by Lieutenant Commander Yoshio Shiga, a veteran of the attack on Pearl Harbor. Shiga's air group would have already been aboard when Shinano sortied for Kure, but four of her 12 boilers were not in service for want of parts. This cut her top speed from 27 kn (50 km/h; 31 mph) to 21 kn (39 km/h; 24 mph) — too slow for planes to launch without a headwind[6].
At 21:00 on 28 November, the American submarine USS Archer-Fish, commanded by Commander Joseph F. Enright, picked up Shinano's taskgroup on her radar[8]. Although Shinano was faster than Archer-Fish, the sub was able to remain in pursuit of Shinano due to the zig-zagging pattern of Shinano and her escorts.[8]. Shinano was also slowed by having only four out of 12 boilers running, as the rest were still nonoperational. Shinano was slowed further mid-pursuit due to the fact that a bearing had overheated on a propeller shaft, forcing lower operating R.P.M's of that engine. Abe's zig-zagging was guided by his assumption that Archer-Fish was part of an American wolf pack. He believed that Archer-Fish was being used as a decoy to lure away one of the destroyer escorts, allowing the rest of the pack a clear shot at Shinano. He actually ordered one of the destroyers to turn back when he spotted it trying to ram Archer-Fish, in part because he believed it left Shinano's bow exposed to an ambush[6].
At 03:05 on 29 November, Archer-Fish dived, and 10 minutes later fired six shallow-running torpedoes at Shinano, with four striking the starboard side between the anti-torpedo bulge and the waterline[4]. Enright later said he'd deliberately set the torpedoes to run shallow (3 m (9.8 ft)) in order to capsize the target[6]. Shinano's destroyer escorts pursued Archer-Fish, forcing the sub to go deep[8].
Though severe, the damage to Shinano was at first judged to be manageable, and the carrier continued under way[4]. However, progressive flooding over the next four hours caused Shinano to list to starboard. Archer-Fish's crew later reported that Shinano was already listing minutes after the last torpedo hit[6]. At dawn, Captain Abe ordered three of the outboard boiler rooms counter-flooded. 60 km (37 mi) from where the torpedoes struck, Shinano's boiler water feed failed shortly afterwards[4]. All efforts to control the flooding failed, in part because most of the crew was not well-trained in damage control[6].
At 07:45, Shinano lost all power, and ceased all forward motion shortly afterward. At 08:50, two of Shinano's escorts took her under tow, attempting to beach her on Cape Ushio. However, the two escorts only displaced 5,000 long tons (5,100 t) between them, not nearly enough to overcome the list. After two attempts, the towing effort had to be abandoned[4][6]. At 10:18, Abe gave the order to abandon ship; by this time Shinano was listing 30° to starboard. At 10:57 on 29 November, Shinano capsized and sank 200 km (120 mi) southeast of Shingū (), taking 1,400 sailors and civilian workers with her. The dead included Abe and both of his navigators[9]. The survivors of Shinano's sinking were quarantined in Japan for several months following her sinking[4].
Postwar analysis of the sinking
Postwar analysis by the US Naval Technical Mission to Japan claimed that Shinano had serious design flaws[10]. Specifically, the joint between the antiprojectile armor on the hull and the anti-torpedo bulge on the underwater body was poorly designed; Archer-Fish's torpedoes all exploded along this joint. Also, the force of the torpedo explosions dislodged an H-beam in one of the boiler rooms. The dislodged beam turned into a giant battering ram that punched a hole between two of the boiler rooms. In addition, the failure to test for watertightness played a role[11]. Survivors claimed that they were unable to control the flooding because the water poured in too fast; some claimed to have seen rivets between seams burst and allow water to surge through. The executive officer reported hearing large amounts of water entering the ship only minutes after the last torpedo hit, and blamed this on the failure to air-test the compartments. Additionally, the ship's list to starboard caused the pumping valves to rise above sea level, which would have made it impossible to counter-flood and right the ship even if they'd worked properly[6].
Footnotes
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 Preston, p. 84
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 "Shinano class aircraft carrier". Parshall, Jon; Bob Hackett, Sander Kingsepp, & Allyn Nevitt. http://combinedfleet.com/ship.php?q=shinan_c.htm. Retrieved 27 January 2009.
- ↑ 3.0 3.1 3.2 3.3 3.4 Preston, p. 91
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 "Combined Fleet - tabular history of Shinano". Parshall, Jon; Bob Hackett, Sander Kingsepp, & Allyn Nevitt. http://combinedfleet.com/Shinano.htm. Retrieved 27 January 2009.
- ↑ Preston, p. 91.
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 Enright, Joseph; James W. Ryan (2000). Sea Assault. New York: St. Martin's Press. ISBN 0-312-97746-8. Originally published as Shinano! (ISBN 031200186X) in 1987.
- ↑ Reynolds, p. 284.
- ↑ 8.0 8.1 8.2 Wheeler, p. 184
- ↑ Wheeler, p. 185
- ↑ Technical Reports, p. 26
- ↑ Technical Reports, p. 27
References
- Preston, Anthony (1999). The World's Great Aircraft Carriers. Brown Books. ISBN 1-89788-458-3
- "Reports of the US Naval Technical Mission to Japan, Ship and Related Targets". United States Naval Technical Institute. January 1946. http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ%20Reports/USNTMJ-200H-0745-0786%20Report%20S-06-2.pdf. Retrieved 2009-01-28.
- Reynolds, Clark G. (1968). The Fast Carriers; The Forging of an Air Navy. New York, Toronto, London, Sydney: McGraw-Hill Book Company.
- Wheeler, Keith (1980). War Under the Pacific. Time-Life Books. ISBN 0-8094-3376-1
- Enright, Joseph F, and James W. Ryan. 2000. Shinano: The Sinking of Japan's Secret Supership. St. Martin's Paperbacks. ISBN 0-312-97746-8
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