A little past three in the morning on November 29th 1944, the American
submarine USS Archerfish fired six torpedoes and sank the 71,000 ton Japanese supercarrier
Shinano. It was the largest ship ever sunk by a submarine and instantly the most successful
US submarine patrol of the entire war by tonnage sunk. This is the extraordinary story of how a
single submarine, skippered by a then unremarkable captain claimed the largest warship then afloat.
The events that led to the attack and sinking of Shinano began years earlier.
She was originally planned as the third ship in Japan’s Yamato class of enormous battleships.
But after the disastrous battle of midway in 1942, it was decided to convert Shinano into
an aircraft carrier while she was still under construction, to be completed in early 1945.
The works to complete Shinano as what would be the largest carrier ever to put to sea were extensive.
Once finished, her colossal hangar would host up to 170 planes, allowing Shinano to
act as a central hub for the maintenance and support of an entire fleets aircraft.
It was a hugely ambitious and powerful design, and one that the Japanese navy got more and more
desperate for as the war situation declined through 1944. In need of something to change
the tide, the completion date for Shinano was rushed forwards to November 1944. This deadline
required a furious effort from the workers at Yokosuka naval shipyard, and it was made even
more frantic when the first US B-29 bombers began to overfly the Japanese mainland on
reconnaissance missions, following the capture of airbases in the Mariana islands. The commerce war
against Japan was entering its final, ruthlessly destructive phase, and the Japanese navy soon
became concerned that Shinano would be spotted from the air and targeted with bombing raids.
They were therefore keen to move the carrier to an anchorage that was less exposed to
American bombers. The carrier was rushed out for builders trials on November 11th,
and then hastily commissioned into the Imperial Navy a week later. The ship was ordered to leave
Yokosuka on November 28th, to head for a safer anchorage at Kure, in the inland sea.
But the carrier’s inaugural skipper, Captain Toshio Abe, was deeply concerned at the state
of his ship. He requested a delay to its departure, as Shinano only had eight of
her twelve boilers operational and had not yet been able to carry out a whole host of
tests to check that each compartment really was fully airtight. The request was bluntly refused,
with the risk from air attacks if the carrier remained at Yokosuka deemed too high.
And so the aircraft carrier Shinano left port for her maiden voyage on the afternoon of November
28th 1944. She w as escorted by the Kagero class destoryers Izokaze, Hamakaze and Yukikaze. There
were more than 2,500 people onboard, including 300 civilian workers who were still completing
parts of the ship. It was a risky voyage- no air cover was available for Shinano so Captain Abe had
been forced to make the passage at night, raising the prospect of an attack by American submarines.
With a third of her boilers out of action, Shinano could only steam at a reduced speed of twenty
knots and so was more vulnerable than usual. By nightfall, the Japanese flotilla was
clear of Tokyo bay and turned to the southwest, beginning a zig-zag pattern
that would take them towards the inland sea. At about t he same time, the American submarine
Archerfish was surfacing after another day spent beneath the waves. Its captain was
Commander Joseph Enright, who was on his first war patrol with the Archerfish. Described by
the historian Clay Blair as a “cautious and uncertain skipper”, more than a year earlier
Enright had asked to be relieved from command of the USS Dace after losing confidence in his own
abilities. Now though, he was back at sea with a fresh submarine and a renewed determination.
At 8.50pm, Archerfish’s RADAR picked up a massive contact 22 kilometres to the north. Before too
long it was visible on the horizon as an aircraft carrier- though unlike any other seen before.
This was a huge potential prize, and Enright was determined not to let it slip through his fingers,
so he authorised the regular use of his boats radar , to be sure of his targets
location at all times as he tried to manuever into an attack position.
Aboard Shinano , the regular emissions from Archerfish’s radar could be heard loud and clear,
but Captain Abe was not unduly concerned. A lone submarine was not in his mind a threat- only a
wolfpack of multiple submarines attacking simultaneously could pose a serious danger
to such a large ship. So at 10.45pm, when the destroyer Isokaze broke away to close down on
the submarine shadowing the group, Captain Abe quickly ordered it back into position.
He did not want his escorts being drawn away by a submarine acting as bait and leaving the carrier
exposed to attack by other submarines. Determined to wrongfoot the wolfpack he
was expecting, at 11pm Abe ordered a turn to the south at 20 knot s, away from the enemy submarine.
Enright pushed Archerfish’s engine to its absolute maximum, but the submarine could only get to
19knots, and by half past 11 contact was lost with the Japanese carrier . Unable to keep up , a
frustrated Commander Enright decided to keep on his boats current course, to be in a better
position if the carrier came back northwards. At 11.40, Shinano obliged, changing course to
steam due west , after an engine fault developed on board, which cut her top speed to 18
knots – slower than what Archerfish was achieving. Captain Abe was keen now to make progress towards
his ships destination, hoping that he had now shaken off the enemy submarine. But as soon as the
carrier swung west, it did not take long for Archerfish to regain contact.
By this stage the boat was south of Shinano and could now turn swiftly to stalk the carrier
from the south. As Archerfish was now travelling faster than t he carrier, it slowly pulled ahead,
positioning itself in an ideal attack position if Shinano came back to her original course of 210.
Commander Enright and his crew had no idea what the Japanese ship’s eventual destination was,
so all they could do was wait and hope, unable to get any closer on the surface without being
spotted again. The hours ticked by, and Shinano remained on her westerly course.
Frustrated, at 2.41am Enright sent off a report to the Pacific Fleet at Pearl Harbor,
giving the carriers position and course. Shinano picked this transmission up a minute
later, and it spooked the Japanese skipper. Captain Abe guessed that it was a message from
the commander of the wolfpack of submarines he was convinced was stalking the carrier,
and that other subs would now be lining up ahead of him for an attack.
He quickly decided to change course, and believing it more likely that hostile submarines would be
lurking closer to the coast to the north, decided to turn the other way. And so , at 2.56 am Captain
Abe ordered Shinano to turn to the south west. Watching from his conning tower seven and a half
miles away, Commander Enright was stunned. The Japanese carrier had turned onto the precise
bearing he had hoped, and was now coming straight for them. Unable to believe his luck, the American
skipper took his boat across the carriers new track and swung it around, lining up for an attack
on Shinano’s starboard side as the 70,000 ton vessel passed by . At 3.06, the submarine dived,
something that the carrier was immediately aware as the radar transmissions they had been hearing
for the last four hours suddenly ceased. This was a sign an attack was imminent. Seeking to throw
them off, Captain Abe ordered a further change in course at 3.10, round to 180 degrees, due south.
By 3.13 Shinano was just 3 kilometres from the submerged Archerfish , which was picking its way
past the escort screen. Determined to press home his attack, Enright stayed on his course as one
of the escorts passed directly over his boat, with barel y 10 feet of clearance between them.
As the propellors receded, Commander Enright wasted no time. He took one more look through
the periscope, and fired six torpedoes at the Japanese carrier in front of him , before
descending rapidly to 400 feet and getting as far away as possible. It was 3.15 am.
The mark 14 torpedoes raced over the now very short distance to the Japanese aircraft carrier.
At 3.17, as Shinano completed her turn south, the torpedoes reached their targets starboard side.
There were four large explosions, as two thirds of the American torpedoes found their targets.
The enormous carrier shuddered, and it did not take long for Captain Abe on the bridge
to realise they had been torpedoed. It was a serious development, but four torpedo hits
should not in theory lead to the loss of Abe’s ship. Shinano wa s a vast ship, with
sophisticated armour and anti-torpedo bulges below the waterline. It had taken 19 torpedoes
and 17 bombs to sink Shinano’s sister ship Musashi the previous month at Leyte gulf.
Captain Mikami, the ships second in command, soon took control of the damage response from
the no.1 damage control centre located in the carriers island. Initial reports were
not good. Mikami discovered that there had been four torpedo hits, three of which were inside
the crucial ‘citadel’ of the ship, where the most important machinery and magazines were positioned.
At each impact site, the torpedoes had punched through Shinano’s torpedo protection
where it was thinner just a few feet below the surface. The result was catastrophic damage.
At the stern, storage units and an empty aviation fuel tank had been blown open, rapidly filling
with water. Inside the citadel, Turbine room 3 had also flooded immediately , along with
boiler room 3, an adjoining oil tank and the air compressor room, with significant loss of life.
As water rushed i nto the ship it began to steadily list to starboard,
first to 5 and then swiftly to 10 degrees. Captain Mikami rang Lieutenant Inada in the
hydraulic pump room , who informed him that 3000 tons of water was being pumped into the
port bilges to try and counteract the growing list, but that it didn’t seem to be working.
It was now past 4am, and the list was up to 13 degrees.
In the bowels of the ship, Lieutenant Commander Miura, the engineering watch
officer was grappling with a situation that was rapidly getting out of control.
The initial torpedo hits were bad enough, but Shinano was still steaming at her
maximum speed of 18 knots , as Captain Abe tried to avoid any further hits from other
lurking submarines. This put a huge amount of stress on the weakened hull, and bulkheads the
length of the ship were buckling under the pressure. Next to the already flooded areas,
water was pouring through ill-fitting doors and rivets, compromising boiler rooms one and seven.
By 5am extensive flooding was now starting to slow the carriers speed as the list steadily increased,
to 15, then 18, and by 6am, 20 degrees. The ship had now heeled so far over that the water intakes
on the port side were above the waterline, meaning the crew could not counterflood any longer. The
ship’s remaining boilers began to shut down,as the freshwater supply failed. Shinano’s speed
dropped to less than ten knots. The starboard hydraulic pump room began to fill with water,
and Lieutenant Inada found his crew trapped, with little prospect of rescue.
Meanwhile on the Bridge, Captain Abe now appreciated the serious danger his ship
was in. He ordered a course change to 300, to simply head for the closes bit of land he could
and try to beach the carrier in shallow water if necessary. By now the sun was up, and Shinano had
travelled a little more than 36 miles since the torpedo impacts, but at a steadily slowing speed.
The situation below decks was becoming incredibly dangerous. Engine room 1 had now also flooded,
along with boiler room 1. In a desperate attempt to right the ship, at 8am Captain Abe ordered the
deliberate counter flooding of all three boiler rooms on the port side. This provided temporary
relief to the list, but with water continuing to pour in it wasn’t enough to save the carrier.
At 8.30, th e starboard hydraulic pump room flooded com pletely.
Shortly before the waters overcame him, Lieutenant Inada addressed the bridge crew
through a voice pipe: “I’m going before you, and I will pray for Shinano and her company.”
An hour later, it was clear to everyone that Shinano was going to sink.
On the bridge Ensign Shoda was dispatched to order the crew in the steering station, who had been
manually operating the ships rudder machinery, to leave their posts and head topside. One of those
rescued by Shoda was sixteen-year-old Seaman Ishii, who would go on to survive the sinking.
More than 1000 crew were now on the flight deck, clinging on as the ever increasing
list once again went past 20 degrees and the water began to lap at the bottom of the island.
At 10.18 Captain Abe, unable to bring himself to issue an ‘abandon ship’ order,
simply addressed his crew to say “you are all released from duty. Save yourselves.”
Shinano finally went down at 10.55, with Captain Abe and other officers going down with the
ship. The three escorting destroyers did their best to pick up survivors for several hours, but
at 2pm they called off their operations. Of 2,515 people onboard that day, 1455 died in the sinking.
As Shinano sank beneath the waves, her attacker had made a clean getaway.
Archerfish returned to Guam at the end of her patrol on December 15th 1944.
After initial scepticism of Commander Enrights claim, Archerfish was eventually credited with
sinking an aircraft carrier of between 59,000 and 72,000 tons, depending on
the source. This made it not only the largest ship ever sunk by a submarine,
it also made Enright’s patrol the most successful by a US submarine by tonnage of the entire war.
On the Japanese side, the loss of Shinano was a devastating blow to plans to mount a fightback
against the Allies. So as not to harm morale, its loss was kept top secret for months, with the
survivors effectively interned near Kure, away from the public. An inquiry was convened under
Vice Admiral Gunichi Mikawa, which essentially found that so many mistakes had been made by so
many people that it was fruitless to assign blame. Poor decision making by Captain Abe had combined
with shoddy build quality, inadequate torpedo protection, an inexperienced crew and bad luck
to create a perfect storm that sent a 71,000 ton supercarrier to the bottom of the pacific ocean.