From the data sent by CHARLES A. THOMPSON (519-1988) we read of the loss of the aircraft carrier SHINANO on 28 November, 1944. This was the largest ship ever sunk by a submarine - EVER! If she had been fully loaded and outfitted for combat, she would have been the largest ship ever sunk by any means ever.

Basic Ship Data:

SHINANO was built as the third of a series of giant YAMATO CLASS battleships (laid down as a battleship toward the end of 1940 at Yokosuka Naval Shipyard). The others were YAMATO and MUSASHI. Huge losses in aircraft carriers during the BATTLE OF MIDWAY in 1942 forced the Japanese to convert this battleship, then still under construction, into a large super-aircraft carrier.

SHINANO was turned over to the fleet on 18 November, 1944 and was at that time the largest aircraft carrier in the world.

Displacement (standard) 59,000 tons
Displacement (full load) 72,000 tons
Displacement (on trials) 68,000 tons
Length at waterline 256 meters
Maximum beam 36.3 meters
Draft 9.75 meters
Design speed 27 knots (could easily exceed this)
Power (main turbines) 150,000 hp (same as used on YAMATO)
Aircraft 100 aircraft
Guns 16 guns, 127mm
Automatic machine guns more than 100 guns, 25mm
Rocket projectiles several launching platforms, 120 mm
Armor belt side armor was reduced from 16 inches to 8 inches when re-built as a carrier

Wartime experiences on the use of aircraft carriers in the Pacific Ocean were taken into account in the design and construction of the ship. The armor of the flight deck had a thickness of 75 + 25mm. Bulkheads of the hangar deck were armored from 15mm at the bow to 50mm at the stern. The hangar was divided along its length into two parts: the bow, which was open, occupied two-thirds of the length of the hangar; the stern was completely enclosed. The ship was equipped with improved systems for storage and delivery of fuel, ventilation, firefighting etc.

Damage to and Circumstances of the Loss of the Ship:

Even before the aircraft carrier was handed over to the fleet, the majority of the crew was aboard (1,900 sailors and officers). In the period of 10 days following commissioning, the loading of supplies and ammunition was accomplished then, because of the air threat in the Tokyo area, it was decided to transfer the ship to the Inland Sea. When the ship departed Yokosuka, only two important construction operations remained to be completed - testing of the compartments with air and sealing bulkhead packing glands for cables and piping.

During the night of 28 November, the carrier was underway in company with three destroyers at a speed of 18 to 20 knots. The American submarine USS ARCHER-FISH, at a significant range, picked up the ship on radar and identified her as a Japanese aircraft carrier. Darkness and a cloudy sky permitted ARCHER-FISH to surface and remain unnoticed. The carrier was proceeding about 1 knot faster than the full speed of the surfaced submarine, but her ZIG-ZAG course permitted ARCHER-FISH to keep up.

At 0300 the carrier suddenly changed course and the submarine appeared in front of her. At a rapidly closing range, the submarine dove to periscope depth and from a favorable position, launched torpedoes at the carrier. The first torpedo struck the stern of the ship and the second struck the starboard side at a distance of about 45 meters from the first. The remaining fish apparently also struck the starboard side, but the exact locations were not precisely established.

The carrier immediately took on a list of 10 degrees to starboard. By counterflooding compartments on the port side, the crew was temporarily successful in holding the list to 12 degrees, but intense flooding of compartments continued. Fires broke out aboard ship. Although firefighting apparatus was in good condition, hardly anyone knew how to use it. There was even a completely ineffective attempt made to put out the fires with buckets of water. A panic broke out aboard. The civilian technical personnel (although wearing military uniforms) refused to obey orders from the officers.

At 0500 SHINANO was still barely underway and continued her gradual list to starboard. Counterflooding of compartments appeared to have essentially no influence. Toward 0600 (three hours after the ship was torpedoed) her mechanical installation went out of commission. Preparations were immediately made to abandon ship. The accompanying destroyers approached broadside to the wrecked carrier and at 0800 began to take of the crew. In all, they were successful in saving about 75% of the personnel on board. The list continued in increase and soon SHINANO rolled over, settled by the stern, and sank.

Conclusions:

SHINANO, a large Japanese aircraft carrier of the latest construction, rolled over and sank in a period of 5 to 6 hours from the torpedo hits in one side.

In analyzing the circumstances of the loss of SHINANO, it is necessary to note that one of the torpedoes struck the stern where there was no underwater protection because of the length of the citadel (and the basic underwater protection) on ships of this type was approximately half of the length of the ship and the stern traverse was located 55 meters from the stern section. The aggrivating circumstances was that all the torpedoes hit from one side. In view of the great number of longitudinal bulkheads and the significant capacity of air compartments in the structural underwater-plating system, the damaging list of the ship naturally grew all the more.

Under these conditions, the righting system again could not be sufficiently effective. Undoubtedly, the lack of watertight integrity of the internal construction of the hull, as these tests had not been finished, contributed to the flooding. The presence of leaks in the bulkheads, both in places where the electric cables passed through and where the piping penetrated, aggrivated the spread of water throughout the ship.

Ships of this type were designed to have a positive metacentric height and not capsize during the flooding of all unprotected compartments or during the flooding of all compartments of the underwater protection on one side. Such design conditions guaranteed the ship a high damage stability. The resistance of the underwater protection system significantly exceeded the destructive potential of American torpedoes of that period. The fact that the damaged ship remained afloat for 5 to 6 hours under the indicated conditions gives evidence of her comparatively high survivability associated with high stability, strong underwater protection, anti-list systems etc.

Among the essential reasons for the loss of the aircraft carrier were the almost complete unpreparedness of her crew to carry out damage-control procedures under conditions of heavy damage, the panic and the disorganized nature of the efforts to prevent flooding and fight fires.

Additional

If there is anyone who does not know, CAPTAIN JOE ENRIGHT (2142-1992)was the Skipper of USS ARCHER-FISH that historic night; and the Japanese Admiral, despite orders to the contrary, went down with his ship.