© 2001 Anthony P. Tully

© Revised May 2020 Anthony P. Tully

(under construction)

July 1935:
With plans for the super-battleships of the Yamato-class in progress, at Yokosuka construction of a brand-new huge drydock to construct and service such ships began. This is Drydock No.6. The dock will be 365.80 meters long, 67.50 meters wide, and 17.00 meters deep.

7 April 1940:
As Drydock No.6 neared completion, construction of the third Yamato-class ship began there.

4 May 1940:
Drydock No.6 is completed. On the same day without delay the groundbreaking ceremony for laying the keel of Hull No.110 will be the third Yamato-class battleship is laid down. The 110th hull built at Yokosuka, it will become SHINANO. In the original schedule, it was to be launched in October 1943, receive its 18-inch guns in April 1944 and commission in March 1945.

12 August 1941:
Construction is temporarily slowed, if not suspended, on Hull No.110 in order to prioritize work shifts for refit and repairs of other ships for the growing national emergency. In addition wartime events in the Atlantic and Mediterranean War had raised serious questions about the utility of further battleship construction at this time.

November 1941:
With war imminent, all large ship construction is reviewed and most cancelled. Production priority is given to submarines and aircraft. No.110 work is halted but with the hull complete to nearly the Lower Deck level is too advanced to simply dismantle. It is judged it makes more sense to complete the hull to a usable state to float and tow out of the drydock. Construction renews at a quick pace because it is desired to clear No.6 drydock for medium carrier construction or repairs of damaged ships. It is believed it can be completed enough to take out by October 1942.

18 April 1942:
Yokosuka Navy Yard is bombed by B-25 bombers during the "Doolittle Raid" on the Tokyo area. Though the carrier RYUHO then under conversion is damaged in its own dock the No.110 hull is not even noticed or damaged in No.6.

30 June 1942:
Following the disastrous battle of Midway the Navy Minister approved and ordered a wartime carrier construction program. As part of this, the Yamato-class No.110 hull is to be removed from No.6 drydock and two Unryu-class carriers constructed there. However, No.110 is now 70% complete and dismantling something so large would be as difficult a project as many constructions.

July 1942:
Shortly after at a IGHQ meeting Vice Admiral Seiichi Iwamura reportedly proposed converting the third Yamato-class battleship to a `floating aviation fortress.' It would actually not carry its own air wing, and would be more like a mobile impervious airdrome for other carriers that would steam in advance of them. However, Kami Shigenori disdained this idea and preferred that No.110 become a true attack carrier, a super-TAIHO. Whatever the concept's precise origin, re-design and reconstruction as an aircraft-carrier was now authorized.

16 July 1942:
The projected specifications for No.110's conversion are laid out. It is to be completed as an armored aircraft carrier, closely modeled after No.130 TAIHO. At the time No.110 had had its turbines and nine of its twelve boilers installed. The floor of the magazines of No.1 and No.3 turrets had been completed, and the bulkheads had risen as high as the Middle Deck level.

September 1942:
With the basic plan completed the laying out of the detailed design work began. (Construction work at the dock remained suspended during this period).

November 1942:
The basic design is completed and detailed blue-printing began. Not long after the end of the year, the re-construction commenced in winter of 1943.

August 1943:
Because of heavy losses in the Guadalcanal and Solomons campaigns and many demands on repair and building facilities, construction is again slow-walked. However, completion is still expected by January 1945.

1 July 1944:
No.110 is named SHINANO, and designated as No.212 and registered as an aircraft carrier. At the Battle of Marianas on 19-20 June the Imperial Navy had lost three aircraft carriers HIYO, SHOKAKU, and worst of all: the splendid new TAIHO of which so much had been expected and planned for. It is decided that it was urgently necessary for SHINANO to be completed to take TAIHO's place in the projected (next) Decisive Battle of the SHO-plans. Marianas had changed all priorities and completion was to be expedited, required to be finished by 15 October 1944. This was to be done by prioritizing only fittings required for the `Decisive Battle'. If SHINANO survived, full completion would be carried out then.

July 1944:
After the Battle of Marianas some last minute incorporations of lessons from the battle are worked into the design where possible. These include installation of concret cofferdams around the aviation-gas tanks. The schedule demanded the carrier be launched (dock flooded) on 5 October with naming ceremony on the 8th, and officially completed on 15 October. Construction now proceeded at a furious pace.

15 August 1944:
Capt. (later RADM, posthumously) Abe Toshio (46) (former CO of OYODO) is posted Chief Equipping Officer.

15 September 1944:
Cdr Kawano Michitoshi (Eng. 32) (former Chief Engineer, HAGURO) and Cdr (Captain posthumously) Sakinaga Yoshiro (54) (former Air Officer, JUNYO) are appointed Equipping Officers.

20 September 1944:
LtCdr/P Naruto Seiji (Pay. 24) (former Paymaster, 25th Special Base Force) is appointed an Equipping Officer.

25 September 1944:
Cdr. (later RADM, posthumously) Nakamura Noboru (52) (former Staff, 2nd Southern Expeditionary Fleet / Southwest Area Fleet) is posted Equipping Officer.

1 October 1944:
Captain Abe is officially designated Commanding Officer of SHINANO. Captain Mikami Tadashi (49) (former Communications Officer, YAMASHIRO), Cdr (RAdm posthumously) Nakamura Kaoru (52) (former Staff, 2nd Southern Expeditionary Fleet / Southwest Area Fleet), Cdr Mikami Haruo (Eng. 35) (former Chief Engineer, KUMA), LtCdr/S Yasuma Takamasa (1936) (former Surgeon, CHIKUMA), and LtCdr Araki Isao (56) (former Staff, Fourth Fleet) are appointed Equipping Officers. LtCdr Shiga Yoshio (62) (former Air Group Commander, HIYO) relieves Cdr Sakinaga as Equipping Officer. A new CarDiv 1 is established, comprised of UNRYU, AMAGI, KATSURAGI, and when ready, SHINANO.

5 October 1944:
0800: The `launch' with flooding of the No.6 construction drydock commenced. However when the water was about 8 meters deep an accidental error causes the outer caisson to open prematurely. This caused accelerated preciptous flooding of the dock which shoves the carrier against the front wall. In fact, the vessel `yo-yos' back and forth a couple of times until the water level equalized. Some workers were cast into the water but fortunately no lives are lost. However, the hydrophone compartment in the bow is damaged and there is slight damage to one of the propeller blades.

8 October 1944:
To keep schedule, SHINANO is towed outside temporarily for the formal naming ceremony. Minister Mitsumasa Yoneuchi attends in the name of Emperor Hirohito. SHINANO is then returned inside the dock. Repairs to the damage use some of the materials of her cancelled sister, hull No.111.

15 October 1944:
Equipping Officers Cdr Nakamura and Cdr Kawano are promoted Captain. Equipping Officer LtCdr Araki is promoted Cdr.

Mid-October 1944:
While repairs are underway efforts are made to attempt to the camouflage the carrier's prescence from aircraft. Several false buildings are erected on the flight deck to obscure its rectangular shape. However, with the dock flooded, a test photograph from overhead revealed the carrier remained all too obvious. (Not least due to the dark "frame" the flooded dock basin made around the distinctive flattop outline) This only increased the urgent pressure on construction tempo to repair the ship and get her to sea.

26 October 1944:
Repairs to the bow and other damage from the dock incident are completed. Very soon thereafter, SHINANO is towed out of the dock to the outer harbor and left moored in the Yokosuka roadstead. Here final work to bring her machinery plant on line continued.

1 November 1944:
Photograped by B-29 while moored outside the entrance to Yokosuka Harbor. (As a result of this growing enemy interest and danger, the decision is made to transfer the SHINANO to Kure, though final fitting out is still incomplete)

5 November 1944:
Capt. (later RADM, posthumously) Yokote Katsumi (52) (former Chief Gunnery Officer, TONE) is posted Equipping Officer.

11 November 1944:
Afternoon: On trials in Kisarazu Bay. The only beam photograph found of her is said to have been taken on this date. (According to one witness, at times the carrier clocked 27.5 knots. The roll amount was 12 degrees on turns.) Take-off and landing tests with aircraft are carried out this day and the next and many observers including LtCdr. Shiga Yoshio are aboard.

12 November 1944:
Conducted successful landing and take-off operations with the new "Shiden" aircraft designed for carrier operations allegedly even fitted with tail-hooks.

15 November 1944:
LtCdr. Shiga Yoshio is appointed as Air Officer.

19 November 1944:
Officially commissioned at Yokosuka and assigned to CarDiv 1. Captain Mikami is appointed XO. Captain Yokote is appointed Gunnery Officer. Captain Nakamura is appointed Navigator. Captain Kawano is appointed Chief Engineer. Cdr Mikami is appointed Damage Control Officer. LtCdr/S Yasuma is appointed Surgeon. LtCdr/P Naruto is appointed Paymaster. Cdr Araki is appointed Communications Officer.

24 November 1944:
By Combined Fleet Dispatch Order No. 550 CinC Combined Fleet Admiral Toyoda directed that SHINANO proceed to Kure for final completion work; escorted by Desdiv 17 (arriving next day at Yokosuka with NAGATO).[1]

26 November 1944:
IGHQ orders that SHINANO embark and transport `Ohka' rocket-glider kamikaze planes of the "Thunder Gods" corps on her voyage to Kure.

27 November 1944:
With crews working in three shifts workers completed packing and loading of Ohka rocket-gliders aboard SHINANO. A request from Captain Abe to postpone the voyage in order to complete more work and train just a few days more is rejected in view of the presumed urgency of the situation. Both the danger of air attack at Yokosuka and the need for the Ohkas in Luzon appeared imminent.

28 November 1944:
1330: Departed Yokosuka for Kure, carrying six `Shinyo' suicide-boats, 50 Ohka rocket-bombs and personnel of the "Thunder-Gods" unit. (It is also said that three attack planes were aboard - possibly for anti-submarine work when it was learned there would be no air cover. SHINANO had operated aircraft, and was to pick up her Air Wing in Kure.) Escorted by ComDesDiv 17 Shintani Kiichi's HAMAKAZE (flag), YUKIKAZE, and ISOKAZE. At this time only eight boilers of the twelve had been completed, but this did not matter as SHINANO sailed with only six fired. This still allowed a maximum of 24 knots if required.
1830: Flotilla cleared approaches to Tokyo Bay.
Action:
- 2245 SHINANO sighted an enemy submarine ahead off the starboard bow. The carrier signaled this to the destroyers but also told them to hold fire since they may not have been detected and the submarine was not too close. (HAMAKAZE in the lead was recalled from already having commenced an attack run)
- 2330 A turbine in the starboard inboard engine room (No.1 shaft) of SHINANO overheated and overall turns had to be slowed to 192 rpm to let it run cooler. SHINANO's speed was reduced to 18 knots.
- 2340 Fleet changed course to due west.

29 November 1944:
Action:
- 0030 What appeared to be a submarine is again sighted. HAMAKAZE was closest but decided to let YUKIKAZE investigate. However, YUKIKAZE did not receive this message.
- 0245 SHINANO sighted what appeared to be a submarine bearing 30 degrees starboard, distance 7,000 meters. The ISOKAZE is signaled to investigate.
- 0309 Near position bearing 198 degrees 108 miles from Omae-zaki lighthouse SHINANO is struck by four torpedoes in the starboard side fired by USS ARCHERFISH.

See diagram of hit locations prepared by NavTech court of investigation that interviewed members of the Japanese "S" inquiry immediately post-war: SHINANO TORPEDO HITS AND FLOODING

- No.3 boiler room floods at once, killing all there, while No.7 aft also floods quickly (but is either abandoned or not in use-no casualties) The No.2 damage control center also floods and has to be abandoned. SHINANO takes on an initial list of 9-10 degrees to starboard but is able to maintain 18 knots. However, very soon the outboard starboard engine room flooded from leaks in its bulkhead and the shaft stuffing gland. (The engine watch escaped safely) Damage control counter-flooded with 3,000 tons of water into the port voids, checking the list at 12 degrees.
- At first the damage - though severe -- is judged manageable. Four boilers and three engines remained online and the carrier is able to maintain speed and course. However, progressive flooding through incomplete fittings spreads, and a heavy list to starboard develops and by 0430 had reached 15 degrees.
- 0500 Starboard outboard turbine stopped. SHINANO's speed drops.
- 0530 SHINANO had steamed 36 miles from where torpedoed and was still making 11 knots, when the list reached 13 degrees. This brought the water intake vales out of the water and as a result it was no longer possible to use the trimming tanks to right the ship.
- 0600 About this time the list had reached 18 degrees starboard; and at this angle the carrier's freshwater evaporator shut down. It was no longer possible to provide fresh feedwater to the boilers. Since no one knew really how to distill feedwater from saltwater, and it was feared it would damage the boilers when the supply exhausted it was decided to secure the remaining fire-rooms instead. SHINANO rapidly lost headway.
- 0730 SHINANO unnavigable.
- 0745 SHINANO flashed request to HAMAKAZE and ISOKAZE to approach to attempt to take in tow by the bow.
- 0800 Captain Abe ordered the men of the Boiler and Machinery Departments to leave their posts and evacuate topside. Before doing so they are to flood all three port outboard boiler rooms Nos.4, 8, and 12 to try to right the ship. This is done, but has limited impact.
- 0830 Flooding Control Station No.2 flooded. Division Officer Capt. Inada Fumio and 9 ratings that had stayed to the end trying to manage the listing and prevent capsizing as long as possible are lost.
- 0850 HAMAKAZE and ISOKAZE took in tow, and building to 3 knots tried to move toward Cape Ushio to beach her. However, the strain grows too great and cables part. Further attempts are unavailing. The tow has to be abandoned.
- 0932 The Imperial Portrait is wrapped and transferred with its messenger to a cutter from HAMAKAZE. However, the boat gets unbalanced by SHINANO's starboard bulge and overturns. The messenger and portrait goes into the water. The list to starboard resumes and increased.
- 1018 Captain Abe gives the order to Abandon Ship.
- 1025 List to starboard 35 degrees. The colors are lowered.
- The YUKIKAZE comes alongside to remove the crew.

Sunk:
- 1055 SHINANO rolled over to starboard completely bottom up.
- 1047 Sinks by the stern in position 33-07'N, 137-04'E, taking down Captain Abe (by his choice), 1,435 officers and men, the 50 Ohka rocket bombs and 6 Shinyo suicide boats. Rescued are 55 officers, 993 petty officers and men, plus 32 civilians for a total of 1,080 survivors (including 3 of the Ohka pilots). In addition, alerted by the rescued messenger, the HAMAKAZE does recover the Imperial Portrait found floating on the sea. Oddly enough, some of the survivors find refuge clinging to some Ohkas that were left floating on the surface. Capt. Abe, Chief Gunnery Officer Capt. Yokote, and Chief Navigator Capt. Nakamura are KIA all of whom are posthumously promoted Rear Admiral. Surviving officers include XO Capt. Mikami and Chief Engineer Capt. Kono survive, as do Chief Surgeon Lt. Cdr. Yasuma, Paymaster LtCdr. Naruto and Chief Communications Officer Cdr. Araki.(Air Officer LtCdr Shiga was not aboard for the voyage, and was awaiting SHINANO's arrival in Kure along with the carrier's intended air group.)

30 November 1944:
1700: ISOKAZE, HAMAKAZE, and YUKIKAZE arrived at Kure. SHINANO's survivors are quarantined till January 1945 on the island of Mitsuko-jima in Kure Bay.

28 December 1944:
The "S" Investigation into SHINANO's loss opened in Tokyo, chaired by Vice Admiral Mikawa Gunichi. In the end it is concluded so many parties were to blame no one is held at special fault. It is determined that essentially a gamble had been taken and because of flaws in construction and the incomplete state of the vessel that gamble had been lost. The committee noted design lessons to be learned.

1 March 1945:
Damage Control Officer Cdr Mikami is appointed XO of Air Group 1081 on 1 March 1945.

31 August 1945:
Removed from Navy List.