The Sinking of I-70

The I-70 in port during May 1941 after a collision with the submarine I-69 during exercises. The submarine was repaired and sent to support the Japanese attack on Pearl Harbor.

Portrait of Lt. Clarence Earle Dickinson, Jr., VS-6

At 0553 that morning Enterprise and its task force, after having passed between Oahu and Molokai on the 9th, was continuing its search toward the north and northeast along the sea lane toward the mainland’s west coast, and launched her first group of planes to fly the morning search patterns. They were looking for Japanese surface ships, aircraft or submarines. It was to be a day of frequent contacts with enemy submarines, intense flight operations, sightings of submarine periscopes as well as submarines running on the surface, enemy torpedo wakes sighted tracking toward Enterprise, aggressive depth charge attacks by Enterprise’s submarine screening destroyers, a zigzagging task force, sharp changes in speed from flank speed to engines stop, and abrupt changes in direction at flank speed with the great ship heeled over twenty to thirty degrees opposite the direction of turn. The day began with a bang.

The last aircraft among the first group to launch lifted off at 0602. They were from Bombing Squadron Six, and within seventeen minutes of the first launch, one aircraft from

VB-6 sighted an enemy submarine running on the surface. At 0618 Enterprise began launching a second group, and completed the launch three minutes later. While the second launch was in progress at 0619, SBD 6-B-17, from VB-6 reported a submarine at latitude 22 degrees 30 minutes north, longitude 156 degrees 30 minutes west, course 080 degrees true – a course nearly due east. At 0630 hours, the plane’s crew reported they bombed the submarine.

The pilot, Lieutenant (jg) Edward L. Anderson, with Radioman/gunner Third Class S.J. Mason in the rear cockpit, was searching an area forty miles south of Enterprise at 300 feet altitude. In his action report of 15 December, he wrote,

…sighted a wake made by [an] enemy submarine. The vessel was close and [the] conning tower [was] sighted above water. The submarine was making a crash dive. I pulled up to 800 feet over the enemy and released a 1000 pound bomb which was seen to explode approximately 50 feet aft and somewhat to port of the submerging submarine’s conning tower. Oil appeared on water. No further evidence of submarine.


The last aircraft airborne in the morning launch was at 0621. At 0627 hours, Ensign Clifford R. Walters, flying SBD 6-B-2 from Bombing Six, reported sighting a Japanese submarine bearing 020 degrees from point option, the point from which the squadron dispersed to begin flying search patterns. He had reached the end of the search mission’s first navigation leg, and after rendering a report and being informed that ten surface vessels he had spotted were Task Force 1, detached from Task Force 8 to meet Saratoga and escort her to Pearl Harbor, he turned toward the Enterprise. In his 13 December action report he recounted what occurred:

…While en route back to the ship, I saw a submarine on the surface. Tracking the submarine in the sun, I was able to see it was large, no flag, and traveling at about 16 knots. I decided to bomb it in a glide bomb but the higher winds pushed me into a dive bomb attack and with little flaps. I dropped the bomb at 1800 feet and was unable to pull out until about 600 feet because I was traveling at a speed of about 240 knots. The submarine submerged just before I was in firing range with the .50-caliber fixed guns. He submerged slowly and blew many bubbles on descent. The 1000 pound bomb landed about 40 feet on the starboard quarter. I believe shrapnel hit the submarine as the bomb had an instantaneous fuze. My Radioman, IVANTIC, J.J., RM3c, strafed the submarine with his .30-caliber free machine gun as we pulled out of the dive. I remained over the spot for a few minutes and the submarine did not surface again, so I returned to the ship. I saw no oil on the surface.

Ensign Walters’ action report suggests he probably had attacked and damaged the I-70. His Imperial Majesty’s submarines I-25 and I-70, were two of the Japanese combatant’s attacked by Enterprise aircraft that morning. I-25 reported being attacked with a depth charge by a TBD-1 “Devastator” of VT-6, but dove to 130 feet, and the depth charge exploded above her, causing no damage. After waiting thirty minutes, I-25 returned to periscope depth and was attacked a second time, and again dove to 130 feet, causing the depth charge to explode above her, with no damage.

The I-70 was less fortunate. She had been damaged by a bomb released by an SBD in the early morning attack, damage that forced Commander Sano’s decision to surface, and continue running on the surface. Considerably smaller and carrying less firepower than the Type C.1 cruiser subs that carried the midgets launched into Pearl Harbor, the Type 6A submarine built in 1934 was 336 feet long, 27 feet abeam, with a hull depth of 15 feet; displaced 1,400 tons normal, 1,785 full, and 2,440 tons maximum submerged; carried a 4-inch instead of a 5.5-inch gun; six instead of eight torpedo tubes; and 14 instead of 20 torpedoes.

The end came in the early afternoon 121 miles northeast of Cape Halava, Molokai, Hawaiian Islands, at latitude 23 degrees, forty-five minutes north, longitude 155 degrees, thirty-five minutes west. Lieutenant Clarence E. Dickinson, the pilot who had, himself, been shot down by swarming Japanese fighters over Oahu the morning of 7 December – costing the life of his radioman/gunner – had his opportunity for payback, and succeeded. He struck with one dive bomb pass, and the submarine sank, leaving four sailors in the water who later perished.

Lieutenant Dickinson, writing in his 1942 book, The Flying Guns, had no way of knowing the identity of the submarine he and his Radioman/gunner sunk that day, but vividly recalled the sequence of events leading to I-70’s destruction.

…the morning scouting flight picked up three or four submarines on the surface. Three or four seen in the area covered by the scouting flight logically meant that there were an awful lot of Jap submarines around. So, about 11:30 in the morning of December 10, Admiral Halsey decided to send three planes to each place where a submarine had been sighted. I was detailed to make this flight.

At that time no one had been assigned to me in place of Miller, [my radioman-gunner killed over Oahu the morning of 7 December.] So I took a lad named [Thomas E.] Merritt, about twenty-one; very nice looking. This young man turned out to be an extremely reliable radioman and gunner, one of the best in the squadron. But this was going to be his first chance for revenge.

The submarine I was to hunt for was supposed to be about 125 miles north of Pearl Harbor. However, when I had flown about 75 miles south I wasn’t expecting to find the submarine waiting for me; that was only my starting point, really. It had been seen at six o’clock approximately where I was by a half hour past noon. Where could it have gone in the Pacific Ocean in six and a half hours? I decided the best thing to do was to fly a rectangular course around the position where the sub had been last sighted and give emphasis to the north and east. I went twenty miles south, then traveled thirty miles on a leg to the east, then began the leg forty miles north. I had left the carrier at noon. It was now about half past one. Nothing but sky and water anywhere in sight.

The wind was blowing pretty much of a gale. There were white-capped waves, but visibility was excellent. I could see twenty-five miles in any direction, possibly thirty miles. Just as I reached the north corner of my rectangle, lo and behold! Way over to the northeast about fifteen or eighteen miles away there was a great big submarine running on the surface. It was pushing to the northeast just as fast as it could go. It was obviously a submarine but it looked to me to be the biggest I had ever seen. I talked to the carrier immediately.

“This is Sail Four…Have sighted submarine. Am attacking.”

The carrier acknowledged my message. I was already heading toward the sub. I was about 800 feet off the water then and to make a good dive bombing attack I would have to climb up to 5,000 or 6,000 feet at least. So I started climbing. I suppose I was climbing while I was talking with the ship. Now, to go straight ahead fifteen to eighteen miles in a scout bomber is one thing, but it is something else to go a mile up while you are going eighteen miles ahead; moreover I was flying right into a heavy wind. It would probably take six or eight minutes for me to get into position to do my job. I had certain chores to do in connection with my craft of bombing. I had to “arm” the bomb mechanically before I dropped it. I had to do certain things to it that would make it explode on contact. Threaded through the fuse of that 500-pound bomb I was carrying were what we call “arming wires.” These arming wires have to be pulled out of the fuse before the bomb is dropped, else it will fall as a dud. When the wires are pulled out, two parts of the fuse move into position, the “vanes” on the fuse rotate properly and on contact the bomb explodes. Consequently the height of futility in bombing is to neglect to arm your bomb. The arming of the bomb is the pilot’s job, but to make sure that none of us forgets in the excitement of the attack, it has been made a part of the gunner’s duty to check with the pilot just as your partner checks you against a possible renege in a bridge game when you fail to follow suit by asking politely, “No spades?”

I had plenty on my mind climbing to a good diving position. I didn’t see how I could stand the disappointment were the Jap to submerge. Next thing I knew he was shooting at me; just as soon as I was within gun’s distance of him the sub had opened up with two deck guns, four or five inchers. The Japs manning those guns were not especially good shots but, after all, this was the second time within three days that I had been shot at and I was a little tired of being on the receiving end. I was getting sensitive, I suppose. However, I had fine faith in that bomb. It is quite an effective weapon if you drop it close enough. Right beside the submarine, in the water, is best.

Those anti-aircraft bursts were giving me just a touch of headache. There wasn’t a great deal of danger from them but they were annoying. I was climbing as hard as I could and then young Merritt called over our radio. “Is the bomb armed, Mr. Dickinson?”

I was busy in my cockpit just that second and did not respond. “Mr. Dickinson, is the bomb armed?” I feel sure I must have said yes a couple of times but this kid back of me wasn’t going to have a failure on his hands. I was climbing and estimating the situation every instant. The Japs were shooting. Merritt was prompting. “Be sure the bomb is armed!” “Look here,” I said, “the bomb is armed. For God’s sake! Relax! Maybe we can get this submarine. Take my word for it, the bomb is armed.”

Those aboard ship hadn’t realized how far I had to go when I reported I was attacking. However, when I was about half way to where I was determined to get, there was a voice in my ears, asking for a report. Was I making progress? With the Jap shooting at me, with my deep concern for fear the submarine would disappear before I could lay my egg and further rasped by Merritt’s well-meant solicitude, I was in no mood to be heckled by the ship. So I told them I would report the progress of my attack as soon as I had time to drop the bomb.

I suppose the Jap’s two deck guns had fired at least twenty-five anti-aircraft shells at me. I had had him in sight for almost eight minutes. Yet he had made no attempt to submerge. All he was doing was turning to the right a few degrees. Obviously there was something wrong with him. He had been bombed once before that day. The plane from our carrier that had found him at six o’clock in the morning had dropped a bomb fairly close to him. So I believe he could not submerge. I can’t imagine a submarine skipper in his right mind staying on the surface to fight a plane rather than dive. Even when I was three or four minutes away, in good working order he might have submerged easily. He did not, so I believe that he had previously been damaged.

Those two deck guns, one forward, one aft, were big enough to sink anything but a battleship. But they were firing a couple of machine guns, too. These were mounted on the platform of the oval, tank-like conning tower. For the second time in three days I could see the head-on, deadly jewel wink of machine guns but the flashes from the muzzles of those two anti-aircraft guns were yellow as lemon cream. Nevertheless the black explosions that occasionally washed a slight tremor into the plane quite definitely were not lemon pies.

I was measuring the sub’s course, measuring my height and getting nicely set when my gunner spoke again. “Is the bomb armed, Mr. Dickinson?” This time I said, rather gently, I think, “Yes.” Then I dived. I had a pretty good dive. All the way down I could see the heathen still shooting. Their faces looked brown, not yellow. I wasn’t close enough to see expressions because I was probably as much as thirty stories higher than the Empire State building when I acted. At the left-hand side of the cockpit there is a handle, the bomb release. You simply pull this back so that it travels an inch or possibly an inch and a quarter, until it will go no further. There is no click or jar but you know you have dropped your bomb.

By the time I was able to pull out of the dive, and turn to get my plane’s tail out of the way of my eyes it was probably fifteen seconds before the bomb struck; it struck right beside the submarine, amidships.

I saw first of all only one gun was firing. I suspect the bomb explosion had killed the Japs at the other gun. In a further space of seconds I had the plane turned and was flying back towards the sub. It had stopped, had no perceptible headway and had started to settle, as nearly as I could tell, on an even keel. The fact she had no forward motion satisfied me right then this was not a dive. She was settling! A little more by the stern than forward. In about three-quarters of a minute after my bomb struck the sub had gone under the water.

The chances are, I think, that the bomb explosion caused the submarine to open up underneath. That would kill her speed. Filling amidships would cause her to settle more or less on an even keel. Right after she disappeared, from her amidships, as near as I could tell, there was an eruption of oil and foamy water, like the bursting of a big bubble. Seconds later, fifteen or twenty, I suppose, there was a second disturbance; another bubble-like eruption of foam and oil churned to the white-capped surface of the sea. This time I saw some debris. I reported to the carrier what I had done and what I had seen. But I was careful to say that “possibly” the submarine had been sunk. You simply can’t be sure on such evidence.

During the flight back to the carrier the young man in the rear seat and I discussed the probabilities. “Looks like we got him, Mr. Dickinson.” “Yes, I think we did.”

“That’s certainly pretty nice, huh?”

If you had seen Pearl Harbor you would think so, too. I said to Merritt: “Glad you didn’t let me forget to arm that bomb.”

This was no time to lose the ship but as I approached the position where I estimated she would be all I could see was a big rainstorm covering the area. I circled the storm without seeing a trace of the carrier. I felt certain she was in the storm but I had a feeling it would be easy to get lost in such weather. At such a time! I had things to talk about. I finally plunged into the rainstorm and there was the carrier.

The day proved hectic for Task Force 8 and the quarries she sought. In addition to the two bombing attacks on surfaced submarines and the sinking of I-70, there were seven other confirmed contacts with enemy submarines, which included non-stop air operations, periscope and conning tower sightings, two torpedo wakes clearly observed aiming for Enterprise, two depth charge attacks by screening destroyers, and gunfire at one submarine observed on the surface by the cruiser Salt Lake City. Throughout the day the two forces were constantly searching and maneuvering for shots at one another, or to spoil shots, weaving, zigzagging, changing speeds and directions.

The day after the loss of I-70 and Task Force 8’s heavy engagement with the Japanese submarines in the vicinity of Oahu, Vice Admiral Mitsoyoshi was aware only that he had heard nothing from the submarine’s commander, and the boat’s status was still uncertain. Nevertheless, looking ahead to operations off the West Coast of the United States, and answering to directives from Imperial General Headquarters, he issued a detailed order to the Submarine Force Detachment now moving toward the coast. On Christmas Eve night, I-15, I-9, I-10, I-17, I-19, I-21, I-23, I-25 and I-26 were to each surface and fire 30 shells on selected targets. Rear Admiral Sato, aboard I-9, was charged to execute the order.

Several facts were evident in Task Force 8’s high number of active encounters with Japanese submarines 7 through 13 December. The enemy submarines were in the waters around Oahu in force, astride the sea lanes between Hawaii and the mainland, and an unknown number were now moving toward the west coast. They would probably arrive on stations off the west coast about 17 December. Between the 10th and the 17th, the enemy would begin taking a toll on shipping.

While Enterprise and the ships and planes of Task Force 8 were aggressively pursuing enemy submarines north and northeast of Oahu on 10 December, the carrier Saratoga, which departed San Diego 0958 hours the morning of 8 December, bound for Pearl Harbor, was refueling the three destroyers in her submarine screen, one at a time. From Destroyer Division 50, they were the Talbot (DD-114), Waters (DD-115), and Dent (DD-116), all World War I “four stackers.” Saratoga, which began flight operations on the 9th, on the 11th dispatched Talbot to pick up the two-man crew from an SBD, plane number 3-B-2, from Bombing Squadron Three (VB-3). The aircraft went down 50 miles distant, and another plane in the flight reported the two men were in their rubber boat.

On 12 December at 1335 hours, Talbot, Waters and Dent, were relieved of screening duties and turned back to San Diego when the ships of Task Force 1, which had been sent by CinCPac to escort and screen Saratoga on into Pearl Harbor, took stations in the formation. The ships in the now-strengthened task force were the heavy cruiser Minneapolis (CA-36), and the newer, more modern destroyers Tucker (DD-374), Selfridge (DD-357), Case (DD-370), and Conyngham (DD-371).

Saratoga entered Pearl Harbor and moored at pier F-9 at 1037 the morning of 15 December without having logged a single submarine contact the entire sortie from San Diego to rejoin the Pacific Fleet in Hawaii. Less then twenty-four hours later, at 1226 on 16 December she was underway again, turning west southwest, soon to join Task Force 14 and deliver additional aircraft to Wake Island. At 1350 hours, while outbound initially to the southeast, Saratoga logged the sighting of Task Force 8 and the Enterprise, which was proceeding to Pearl Harbor for refueling and provisioning for further operations.

While Saratoga and her newly formed task force were en route to Pearl Harbor from San Diego, Task Force 12, with the Lexington, was returning from the cancelled delivery to Midway of 18 Marine Vought SB2U-3 Vindicators from VMSB-231 squadron at Ewa. On orders from CinCPac, Task Force 12 turned around the morning of 7 December to search for the Japanese carrier strike force while maneuvering toward Pearl Harbor. At 1152 hours, as Lexington and her screens were steaming northwest toward the harbor’s entrance, the heavy cruiser Indianapolis (CA-35) reported a torpedo wake on the cruiser’s port side and the task force began maneuvering to avoid additional torpedo launches at Lexington.

At 1621 hours, another submarine contact was reported on Lexington’s starboard bow, and she changed course left to avoid a torpedo wake that had been sighted. Escorting destroyers attacked the intruder with depth charges. Unknown to Lexington and Task Force 12, the depth charge attacks had taken their toll on the Japanese submarine I-68, whose captain was Commander Otoji Nakamura.

Ordered to patrol on a station 20 to 50 miles southwest of Pearl Harbor, Nakamura vainly attempted more than once that day to penetrate the submarine screen and torpedo Lexington. For his trouble I-68 was repeatedly hammered by 21 near miss, depth charge attacks. The attacks were uncomfortably close to being fatal for I-68 and its crew. The last attack wrecked many of the submarine’s battery cells, and caused flooding in her aft torpedo tubes. Nakamura decided to terminate I-68’s first patrol against the United States Navy, in support of the Combined Fleet’s Pearl Harbor operation, and brought his crippled submarine limping slowly back to Kwajalein, where it arrived on 28 December – a long, and undoubtedly tense 15-day journey for the crew.

Following another rapid turnaround, Lexington was again underway from Pearl at 1357 hours on 14 December, and at 1732, saw Saratoga and her task force disappear over the horizon as she returned to refuel, take on aviation fuel and provisions, for the next sortie. Steaming on a southwesterly course as part of Task Force 11, by shortly after midnight the morning of 17 December, Lexington and the commanders of all the task force’s ships knew they were embarked on a raid on the Japanese-held Marshall Islands, in support of Saratoga’s planned delivery of additional aircraft to Wake Island.

Saratoga left Pearl on 16 December, steaming toward the west, southwest with four destroyers providing plane guard duties and submarine screen: the destroyers Blue (DD-387), Henley (DD-391), Helm (DD-388), and Bagley (DD-386). At 1215 on 17 December, she commenced joining Task Force 14, a powerful force consisting of the heavy cruisers San Francisco (CA-38), Astoria (CA-34), and Minneapolis; destroyers Mugford (DD-389), Selfridge, Patterson (DD-392), and Ralph Talbot (DD-390); the tanker Neches (AO-5) and seaplane tender Tangier. Finally, Lexington and Task Force 11, supporting Saratoga and Task Force 14 were about to take the fight to the enemy.



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