Mounted on the after deck of the “mother” submarine I-24, mini submarine HA-19 is boarded by its crew, Kazuo Sakamaki and Kiyoshi Inagaki, in the pre-dawn hours of December 7, 1941. Painting by Tom W. Freeman
On 28 November 1941 the Japanese First Special Attack Flotilla, consisting of the submarines I-16, I-18, I-20, I-22 and I-24, each carrying a single Type-A midget submarine clamped to the deck abaft the conning tower, began their journeys across the north Pacific to Hawaii. Aboard the I-22 was Captain Hanku Sasaki, commanding the flotilla, and he had issued orders that the submarines were to maintain a twenty-mile gap between one another as they journeyed across the ocean. Once out of Japanese territorial waters each submarine skipper informed the crew of their mission, and the purpose of the strange cargo they were hauling. Aboard the I-22, the skipper, Commander Kiyoi Ageta, declared to the assembled complement packed into the control room and the corridors leading away fore and aft: ‘Our ship is sailing for Hawaii now. Our objective is to discharge the special-type storage tube [a reference to the classified Type-A] to attack Pearl Harbor.’ The leader of the midget submarines once the flotilla had launched from the mother ships was Lieutenant Naoji Iwasa who was also based aboard the I-22.
Captain Sasaki’s plan of action for the five midget submarines constituting his Special Attack Force was simple. The midgets were to penetrate Pearl Harbor undetected and stay concealed inside the harbour until the main air assault began. Several options were then open to the midget submarine skippers. Firstly, once the first Japanese aircraft appeared overhead, they could immediately begin attacks on American warships inside the harbour. Secondly, the midget submarine commanders could wait for the lull between the first and second Japanese aerial waves, and attack then, creating an offensive bridge between the first two aerial assaults. Thirdly, the midget submarines could continue to remain concealed throughout the duration of the carrier plane assaults, only to emerge from the depths with the coming of darkness, and as the Americans began cleaning up launch their attacks by travelling anti-clockwise around Ford Island. Regardless of which plan the submarine skippers activated, their aim was to expend their torpedoes and then depart Pearl Harbor and make for the rendezvous point with the mother submarines at Lanai Island and recovery. Of course, these plans hinged on any of the five Type-As actually penetrating the entrance to Pearl Harbor undetected.
The weapons, which the First Flotilla was to launch against Pearl Harbor hours before the arrival of the main aerial attack force, were intriguing creations reflecting Japanese ingenuity and the advance of naval warfare. The vessels were not small, each Type-A midget submarine measuring 78.5 feet in length and weighing forty-six tons. A two-man crew consisted of a junior officer who commanded the boat and an enlisted man who acted primarily as helmsman. The Type-A could managed 19 knots submerged, and had a potential maximum range of 100 miles if running on the surface at a conservative 2 knots. The midget would approach its target surfaced until diving for the final attack run. The role of the junior officer midget commander was to give helm orders and operate the submarine’s periscope. The commander decided the submarine’s course, speed and depth, and, of course, targets, and transmitted these orders to the petty officer helmsman. The petty officer was charged primarily with control of the helm, and he was required to keep his hands on the wheel for the duration of the mission as the midget was extremely sensitive and the helmsman could easily lose control of the vessel. The petty officer was also required to dive and surface the boat by pulling and turning an assortment of valves that operated the midget’s ballast tanks. Finally, when given the order by the commander, he was charged with firing the two 17 feet long 18-inch torpedoes loaded in the midgets two ‘under and over’ tubes in the bow. Each torpedo was packed with 300 pounds of TNT. The single greatest challenge faced by the midget crews, apart from heat exhaustion and being unable to stand up inside the vessel for hours on end, was maintaining the submarine’s balance, the Type-A being renowned for its instability at sea.
The ‘mother’ submarines that would transport the midgets to the waters around Hawaii were all of the Type-C1-class. Five of these vessels were completed in 1940 and 1941 respectively, and they were dedicated midget submarine transports. As well as the Pearl Harbor operation, the Type-C1 submarines I-16 and I-20 launched their midgets outside of the Royal Navy’s base at Diego Suarez in Madagascar on the night of 30 May 1942. Although neither the crews or the midget submarines themselves returned to the ‘mother’ ships they did manage to damage the old British battleship HMS Ramillies, and to sink the tanker British Loyalty inside the anchorage. The very next night, 31 May, thousands of miles to the east, the I-22 and I-24 (along with other Japanese submarines) launched their midgets in an attempt to penetrate Sydney harbour in Australia.
In November 1942 the I-16, I-20 and I-24 all launched midgets off Guadalcanal, but the damage inflicted to a single American transport was a heavy price to pay for the loss of all of the Type-A midgets that participated in the operation.
When fully loaded the 358.5 feet long Type-C1 submarine weighed in at 3,561 tons, and was powered by twin diesel engines generating 12,400 horsepower. This meant that the submarine could reach 23.5 knots on the surface, and an equally impressive 8 knots when running submerged on 2,000 horsepower electric motors. At a fuel-conserving 16 knots a surfaced Type C1 could sail 14,000 nautical miles without refuelling. However, the boats’ trim characteristics were shot to pieces by each having a forty-six ton midget submarine armed with two torpedoes secured to their decks. The submarines travelled submerged by day to avoid aerial detection, coming to the surface at night to charge their batteries. Heavy winter seas constantly washed over the submarines’ decks as the maintenance crews charged with taking care of the midgets clambered and skidded about. The crewmen had to tie themselves to the submarines with lifelines, and many were washed overboard by the waves, only to climb back onto the decks bruised, exhausted and coughing up seawater. Onboard the I-24 one of the midget’s torpedoes was damaged when the mother ship submerged, and it took the crew a full night in foul weather to fit a new torpedo, manhandling the steel fish up from inside the cluttered and cramped interior of the I-24 and into the midget.
Unlike the Type-B1 submarine utilized by the Japanese in patrolling the American west coast in 1941–42, the Type-C1 was not fitted with a reconnaissance aircraft. Armed with a total of twenty torpedoes, eight torpedo tubes were arranged in the bow, served via two separate torpedo rooms located one above the other. The type also mounted a 140mm (5.5-inch) deck-gun, and a rather inadequate single .50 cal. machine gun for anti-aircraft defence. One hundred and one men were required to crew each Type-Cl submarine, a huge complement for a submarine of the era and once again not matched or surpassed until the nuclear age.
As the I-22 crept closer to Oahu, Sasaki watched the coastline intently, but little stirred ashore in the darkness. A few lights were visible and an occasional searchlight beam punched out into the night sky. Sasaki’s confidence soared, and he began to believe that the boys of the Special Attack Force really would be successful and prove the value of their training and their innovative new equipment. As the five midget submarines and the ten hand-picked officers and seamen prepared to strike at the mighty American fleet resting at anchor, Sasaki had ‘…a feeling of confidence and a renewed hope that the attack would be successful’. The I-24’s midget developed a further problem, this time a malfunctioning gyro-compass, a vital piece of equipment without which navigation would have been almost impossible. Ensign Kazuo Sakamaki, the midget’s commander, and Petty Officer Second Class Kiyoshi Inagaki, the crewman, worked feverishly to correct the problem and insisted that their mission should go ahead even if the compass was not fixed in time, demonstrating both their eagerness to complete a mission they had spent months training for, and a willingness to disregard their own lives in the process. Commander Hiroshi Hanabusa, skipper of the I-24, reluctantly agreed to this request, not overly keen to send men on one-way missions, because as an experienced seaman he knew full well that the chances of Sakamaki and Inagaki returning from the mission would be remote with such faulty equipment to contend with.
As the sun slowly set on Saturday, 6 December 1941, the five Japanese mother submarines had assumed their midget launch positions approximately eight miles south of the entrance to Pearl Harbor. The radio operators aboard were periodically picking up Hawaiian music from the shore that echoed eerily through the boats as men moved about making last minute adjustments to their equipment, and officers peered intently through periscopes at the darkened land before them. Slightly after midnight the I-16 began the launch of Sub-Lieutenant Masaharu Yokoyama, aged twenty-two, and his midget. After the launch the I-16 was to proceed to the second, and some would have argued even then, rather unrealistic stage, of the flotilla battle plan: to await the return of the midgets from their attacks on Pearl Harbor. The five big submarines would position themselves seven miles west of Lanai Island, which itself is eighty miles east of Pearl Harbor. There the plan called for them to wait for two days before departing the area. When (if) the midget submarines managed to locate a mother submarine at this location, the midget’s crew was to be recovered and the Type-A then scuttled. Because the mother submarines would fan out off Lanai Island, more than one midget might rendezvous with the same submarine, so it was decided that recovery of the Type-As was impractical. The exhausted but hopefully victorious crews would have priority, as the equipment could be replaced. All of this was rather academic, as many officers and men aboard both the mother submarines and midgets knew, for the midget crews had already made their peace with God, and were prepared to sell their lives for the sake of the Emperor.
Yokoyama and his crewman, Petty Officer Second Class Sadamu Ueda, had already made their preparations for what they believed to be their final voyage. Should they be killed they would become ‘War Gods’, venerated at the Yasakuni Shrine in Tokyo. They could take satisfaction that if they died the Emperor himself would visit the shrine each year to pay his respects and pray for their souls. Religious rites had been conducted aboard the submarine, prayers said, and final farewell letters penned to their families back in Japan, the men enclosing locks of hair and fingernail clippings so that their families would have something physical to cremate should they perish. Both men had dressed in clean uniforms, as Shinto rites dictated, and with souls and bodies purified they had clambered up into their midget submarine from inside the I-16. The telephone link between the midget and the mother submarine was disconnected and at 12.42 a.m. on Sunday, 7 December, the midget lifted off under the water and departed for war.
Aboard the command submarine I-22 Lieutenant Iwasa, leader of the midget submarine group once they had left the mother ships, and his crewmen, Petty Officer First Class Naokichi Sasaki, clambered aboard their vessel. Both men carried family swords strapped to their backs in white cloth sashes. Just before Iwasa disappeared up the ladder into the Type-A he briefly addressed the crew of the I-22. He was full of gratitude for their assistance in getting him and Sasaki to the target area: ‘Our work begins now. Believing in divine help, we are about to depart to do our utmost to fulfil our final task so as not to betray your trust and expectation in us,’ he said, adding, ‘I pray for the future successful battles of I-22. Farewell.’ Iwasa bowed to the crew, who returned his salute, and then was sealed inside the midget. Grasping the inter-submarine telephone, Sasaki spoke to Iwasa for the final time before the midget departed. ‘Congratulations in advance on your success’, he said, ‘I hope you will do your job well. Good luck!’ Iwasa thanked his commanding officer for bringing all of them this far, and his final words indicated his acceptance of the nature of the coming mission when he said, ‘I wish you [Sasaki] to look after my private affairs.’ With the final farewells said the midget was released into the open sea at 1.15 a.m. The I-22’s crew faced the direction the midget had sailed and saluted in silence. It was now a waiting game, waiting for news of a series of successful attacks made by the men they had come to know during the journey across the Pacific, and a period of waiting for their triumphant return, however remote that possibility appeared.
A similar scene to that being played out aboard the I-22 had just concluded aboard the I-18, as Sub-Lieutenant Shigemi Furuno and Petty Officer First Class Shigenori Yokoyama lifted off and motored towards Pearl Harbor. Next to depart was Ensign Akira Hiro-o and Petty Officer Second Class Yoshio Katayama from the I-20. Aboard the I-24, the midget’s defective gyro-compass was still not functioning properly, so Sakamaki determined to navigate towards Pearl Harbor at periscope depth instead, navigating by eye. It was a suicidal decision, but both men were determined not to be left behind kicking their heels while their comrades made history. They were the last midget to depart, and lifted off at 3.33 a.m. The loss of the gyro-compass was soon keenly felt by Sakamaki, as he vainly tried to hold the submarine on a course for the harbour by taking regular periscope readings, but the midget floundered about, taking a long time to edge towards his objective as the dawn fast approached. All of the midgets were supposed to penetrate the entrance to the harbour before daybreak, and be in position to time their attacks with those of the carrier task force aircraft. This became increasingly remote for Sakamaki and his submarine as the slow progress meant he would arrive at the entrance to Pearl Harbor after the other midgets, and the American base would be fully alert to a Japanese presence.
The first line of defence that the five Japanese midget submarines would encounter, and have to slip by unnoticed if they had a chance of penetrating the harbour, were three American minesweepers, the USS Crossbill, Condor and Reedbird. Their job was to patrol the harbour approaches, and a First World War-vintage destroyer located behind them supported them in this task. The USS Ward had been launched during the middle of 1918, though she had not seen any action during the earlier conflict. In fact, the Ward had never fired her guns in anger, and after the First World War the vessel had been mothballed and placed in reserve at San Diego until called up for service in early 1941. Commissioned back into service, and assigned to the US Pacific Fleet as a harbour defence and patrol vessel, she was placed under the command of thirty-five year old Lieutenant William Outerbridge. At 3.57 a.m. the Condor reported sighting what appeared to be a small submarine periscope about two miles outside of the harbour buoy, and the Ward motored over to assist in a thorough search. The Ward conducted a sonar search but turned up no contacts, and after ninety minutes gave up and returned to her original patrol sector.
The next line of defence designed to prevent unauthorized penetration of Pearl Harbor was an anti-submarine and boat net stretched across the harbour mouth. Sections of this net could be opened to permit the passage of vessels into and out of the harbour, and it was the job of the patrol vessels to monitor who was coming and going. Around 5 a.m. the patrol boats Condor and Crossbill headed into the harbour through a gate that was opened for them. The gate was left open as the USS Antares, a navy repair ship towing an empty steel barge, was expected to pass through shortly afterwards. Sub-Lieutenant Yokoyama, aboard the I-16’s midget, saw his chance and decided to follow the Antares through the gate, hopefully fooling the sentinels on watch. Lookouts aboard the Ward watched the Antares pass in front of their vessel as she made her way towards the gate. Something, however, caught their attention, for their appeared to be an object moving in the water between the repair ship and the barge. After some animated discussions aboard the Ward, it was concluded that the object was most probably a loose buoy. Pearl Harbor had received many submarine sightings over the past year, all of which had turned out to be false alarms, and no one was in the mood for jumping to conclusions just yet. The sun was up by now, and the officers and lookouts took up their binoculars and trained them on the object in the water for a closer look. The ‘buoy’ appeared to be travelling at about 5 knots, and no one knew of an inanimate navigational marker doing this before. Lieutenant Outerbridge faced a dilemma: perhaps the object was some kind of new secret weapon being developed by the US Navy, and if he fired on it the consequences for him could have been dire. However, he had not been informed by 14th Naval District to expect any such activity in his sector, and the object was, after all, inside the restricted zone. Having made up his mind to attack the object, Outerbridge ordered the guns manned and the men to battle stations. By now seamen aboard both the Ward and the Antares were reporting that the object looked much less like a buoy, and much more like a small submarine conning tower cutting the surface of the water like a shark’s dorsal fin. A Catalina flying boat circling overhead had also taken an interest in the object, and dropped some smoke bombs to mark its position for the warships.