September 1st, 1944, Sea of Japan, 08:34:
Kaigun-shōsa Yamashita sat on the bridge of the destroyer Take. He commanded three Matsu class destroyers with the task to patrol the area between Hakodate and Aomori. Since the Event the Nihon Kaigun had ordered all carriers, battleships, cruisers and many destroyers back to the home waters of the Sea of Japan.
Those ships were to be refitted with German technology. Like his ship. Armed with 37 mm guns, an 2 4-tube 375 mm Bofors ASROC launcher and advanced German SONAR and RADAR his ship was much better equipped to take out US submarines. These ships had been commissioned a few weeks ago and this patrol mission was supposed to be a shakedown run in relatively safe waters.
Only a few nautical miles away Commander Thomas Benjamin Oakley Jr. on the USS Growler tried to slip through the defences to attack the Japanese fleet in the Sea of Japan. He knew, that this was a difficult task. He remembered the success Prien had at Scapa Flow. But this time 20 boats were attempting this. Five would try it at the Kuril islands, another five here and ten at Tsushima.
It was a suicide mission. A mission that only went forward as Halsey had convinced Nimitz, that some success was needed in the Pacific. He feared that more units would be moved to Atlantic Command. A victory might convince Roosevelt to send more ships to the Pacific instead. The surface fleet was unavailable, so orders were sent out to submarines still in the Pacific. Twenty submarines were ordered for transfer to the Atlantic. It seemed the British had suffered heavy losses. The Brits. If they couldn't deal with the Germans, it was their problem. Pearl Harbor had to be avenged and the fight against the Japanese continued.
He had heard rumors. Rumors that mentioned that Germany was replaced by one from the future. Bullshit. The Germans must have gotten some new toys and the rest were excuses made by HQ.
In the distance he spotted three enemy warships, likely destroyers. Deciding to stop and lie in wait he gave orders for silent running.
Cmdr. Oakley was about to contact the other boats when a violent thump rippled through his submarine. Only a few hundred meters away USS Shark hit a mine on the outer edge of a defensive minefield the Japanese had laid in 1942. The resulting explosion was large enough to be visible to the Japanese a few kilometers away.
At once Yamashita ordered his ships to investigate the explosion. He suspected US submarines to be the cause. That had to be investigated. Yamashita ordered to use active SONAR.
Oakley cursed. Not only USS Shark had hit a mine and was lost, the Japanese ships had noticed them.
On the Take Yamashita's sonar officer reported underwater contacts. Soon a spread of torpedoes fired by a submarine could be seen, but was easily evaded. It brought the Take into a position, where the submarine was about 2,000 m in front. The Japanese ship fired 8 ASW rockets at the target. The ASW rockets entered the water with a small splash. For a moment the sea was calm, but then three massive water piles emerged and wreckage soon floated to the surface.
On Growler Oakley tried to evade the three destroyers by diving. His boat vibrated forcefully when one of his unit's submarines had been sunk. USS Swordfish was the leading boat and thus had to be the victim. However, he heard the ping of the active sonar. His boat had been detected. Suddenly a series of depth charges detonated around his boat, although the destroyer was still over a nautical mile away. His boat was damaged, but still operational. He thought, that the explosions would cause a temporary loss of SONAR contact, but he was wrong as the ship appeared on the surface over him and dropped depth charges. The depth charges were far enough to not destroy the boat but still close enough to cause damage.
Yamashita was pleased. Matsu had attacked yet another submarine with ASROCs and was able to follow the assault up with depth charges. The SONAR was so good, that the underwater explosions did not cause a loss of contact. Momo, his third destroyer, was engaging a third submarine. It seemed damaged, as Momo reported oil slick. The attack continued.
Oakley felt the rumble of another underwater explosion not far away. It seemed either USS Seawolf or USS Tuna were sunk. But he couldn't think about that now, as he was in deep trouble himself, as another destroyer had caught up and engaged him. A pattern of depth charges hit the boat, damaging it further. His engineer told him, the battery bank was hit and chlorine gas was flooding the engine room. Oakley sighed having nothing left to say at this point. He ordered to surface the boat to let the crew escape. He would then scuttle the boat.
On the Take Yamashita had ordered to help Matsu with her opponent, while Momo was looking for other submarine. Soon after the next attack by Take, a submarine surfaced. It was immediately fired upon by all three destroyers. Yamashita soon realised that the submarine surfaced to let the crew escape and called for ceasefire. 46 of the crew were rescued. Cmdr. Oakley was not with them, as he stayed behind to scuttle the boat. His actions would be in vain as German divers dove on the boat about a week later and collected valuable material.
One submarine was left. USS Tuna under the command of Cmdr. Edward Frank Steffanides. He had settled his boat at the bottom of the sea, waiting for the destroyers to retreat. Around midnight the following day he surfaced and sent a report of the operation's failure to Pearl Harbor. His boat needed fresh air and thus was unable to dive until it could be replenished. Unfortunately, a Japanese patrol plane detected the surfaced USS Tuna with its newly fitted surface search radar. After a short and intense bombardment the submarine quickly sank. A corvette nearby was only able to rescue Cmdr. Steffanides and two ratings, who were on the bridge and were able to jump into the water to escape.
Operation Morningstar was a disastrous failure. Of the 20 boats that took part only 4 survived. 10% were lost in a single engagement. As a result, 20 more submarines had been redirected to the Atlantic with general US naval presence decreasing in the Pacific over the next few months. Furthermore the introduction of convoys and significantly improved ASW capabilities of the Japanese navy lead to higher US submarine losses. At the turn of the year of the 160 submarines previous year hardly 100 of them were left in operational condition. That meant only 33 were at the front, another 33 coming or going and 33 repairing in the yard. And the losses only continued to rise. The crews and submarines could be replaced, but the crews became more and more "green", leading to increasingly worse performance and losses.
The news of these defeats were not heard in the light of the catastrophic defeat in the Battle of Alta and the attacks on New York. However, it allowed Japan to reduce their losses and pressure on limited resources. Resources, that were used to upgrade the main fleet, build more sub-chasers and aircraft.