PEARL HARBOR, Hawaii, 
Dec 7, 1941

WE HAVE ATTACKED FIRED UPON AND DROPPED DEPTH CHARGES UPON SUBMARINE OPERATING IN DEFENSIVE SEA AREA.

Received by the Bishop's Point radio station, this message was at once relayed to the Officer in Charge, Net and Boom Defenses, Inshore Patrol; the Communications Officer, Fourteenth Naval District; and the ComFourteen Duty Officer.

At 0712 the ComFourteen Chief of Staff was notified, and the Duty Officer of the Commander-in-Chief, Pacific Fleet, at 0715. Subsequently, Admiral Bloch, Commandant of the Fourteenth Naval district, received word of WARD's message. The relief ready duty destroyer MONAGHAN was dispatched to join forces with WARD. But no alert was sounded.

There had been previous reports of submarine contacts off Hawaii, reports which had proved unfounded, and the impression persisted that WARD had been mistaken.

Apparently previous cries of "Wolf!" had deadened the impact of any submarine alarm. Other modulating factors influenced the situation. Although strained to the breaking point, Tokyo - Washington relations did not appear on the verge of a violent fracture.

Taking their orders from Washington, the military and naval guardians of Pearl Harbor had been somewhat misled by dispatches received on November 7th.

At that date Admiral Husband E. Kimmel, Commander-in-Chief of the United States Fleet with Headquaraters at Pearl Harbor, had been advised, "Japan is expected to make an aggressive move within the next few days." But reference was made to "an amphibious expedition against either the Philippines, Thai or Kra Peninsula, or possibly Borneo."

At the same time, Lieutenant General Walter C. Short of the Hawaiian Department received official warning that a hostile Japanese move was "possible at any moment."

However, he was ordered to take defense measures in a manner that would not "alarm the civilian population or disclose the intent." Thereupon General Short alerted his department against sabotage and placed Hawaii under a condition of "limited preparedness."

It is not within the province of this volume to criticize American defense measures, or lack of them, which permitted a large Japanese carrier force to attain striking distance of the Hawiian Islands and launch a devastating surprise attack.

Errors in judgement were not confined to any one department or branch of the Armed Services - radar detection of the approaching planes at 0702 was ignored, and the antitorpedo net which had been opened for the minesweeper CONDOR remained open for nearly an hour after the attack began.

Of course to students of submarining, however, it is the build-up to the surprise assalt and the part played therein by strategically employed submarines.

Admiral Yamamoto, Commander-in-Chief of the Combined Japanese Fleet, had formulated the Pearl Harbor attack plan the preceding January. As early as July, Japanese submarines were reported in Hawaiian waters, apparently keeping the approaches to Pearl Harbor under surveillance.

Yamamoto completed his planning by mid-September. Submarine contacts were sporadically reported by American destroyers in the Hawaiian area during the ensuing autumn weeks.

Details of the surprise raid and date of its execution were promulgated to all Japanese fleet and task force commanders on Novermber 5th. As previously mentioned, there was increasing evidence of Japanese submarine activity off Hawaii in November.

On November 22 Yamamoto's striking force assembled in the Kuriles, and on the 26th it set out on a circuitous North Pacific course for the target islands. On December 6 the Japanese commanders received the fateful code-phrase:

  CLIMB MOUNT NITAKA

Early morning, December 7, the carriers were in range, some 200 miles north of Oahu. And a squadron of Japanese submarines (Sixth Fleet Submarine Force) was in position off the entrance to Pearl Harbor.

With this squadron were five midget or "baby" submarines. It was one of these babies which WARD had sunk at dawn, thus drawing first blood and giving the assailant the dubious honor of enduring the first casualty in the Pacific War.

Meanwhile, a midget-submarine slipped undetected into the open harbor entrance, and eased into the inner harbor early that Sunday morning. This pocket-size submarine's casual junket around Pearl Harbor is a feat every submariner will recognize as remarkable. Its presence unsuspected, the underwater footpad was hugging the bottom off Ford Island when the air attack began.

While the harbor was being bombed, this submarine launched both of its torpedoes. The first passed between the seaplane tender CURTISS and the cruiser RALEIGH, and exploded on the Ford Island shore. The other burrowed into the mud not far from the old timber-covered target ship UTAH. The Japanese announced a battleship of the OKLAHOMA class torpedoed by a midget submarine, but the records cancel the report as hearsay.

Promptly sunk by CURTISS for its pains, the midget in question constituted the enemy's second submarine loss. It is possible this submarine was the one originally sighted by CONDOR.

One small submersible, soon to be a needle under a haystack of shattered American warships, might seem of little account. But this sinking of an ememy submarine in the heart of Pearl Harbor emphatically underlines the most important faculty of the undersea boat - its ability to penetrate naval defenses, conduct an unobserved approach and deliver a surprise attack. While the attack in this instance failed, the approach was nonetheless successful.

In this respect it gave observers a hint of the undersea warfare to come.

Another Japanese midget submarine lost its bearings and crawled up on a reef near Bellows Field southeast of Kaneohe Bay. There, the day following the raid, it was captured intact. Also captured intact was the Japanese commanding officer, Sub Lieutenant Sakamaki, who swam ashore and surrendered, preferring Hawaii to hara-kiri. A product of the Japanese Naval Academy, class of 1940, Sakamaki dolefully informed his interrogators that he had failed in his mission.

His mission, of course, had not been to become America's first Japanese P.O.W. Leery of the freak submersible, Army officials wanted to blow it off the reef with gunfire. Timely intervention of Captain F.A. Daubin, commander of the Submarine Base at Pearl Harbor, and his executive officer, Commander M.M. Stephens, rescued the miniature submarine for scientific examination. Quick work by LCDR D.T. Eddy, engineer and repair officer at the Pearl Harbor Submarine Base, salvaged the craft.

The captured midget submarine bore the designation "I-18," obviously relating it to a Japanese I-class ocean-going submarine which must have served as its "mother." Found on a chart recovered from the midget were notations, "I-16,""I-20," "I-22," "I-18," "I-24." spotted in the entrance channel between Hammer Point and Hospital Point. However dubious it origin and unique its design, every baby must have a mother, and the implications were clear. At least five Japanese "mother" submarines had been lurking in the waters off Pearl Harbor.

The mother submarine carried her dwarf offspring on the main deck abaft the conning tower where it was fastened to the pressure hull by heavy clamps. Tied to its mother's apron strings by a 200-mile cruising radius, the baby had to be "piggy-backed" close to its objective before launching.

The Japanese midget submarine captured at Bellows Field was approximately 79 feet long, with a 6-foot beam, electrically powered, and capable of a maximum speed of 24 knots and a cruising speed of 4 to 6 knots.

Thin hull plating limited the boat to shallow submergence. A forward compartment carried torpedo tubes and compressed air tanks. Electric motors and propeller drive shaft were compartmented in the stern. At either side of the conning tower were battery compartments.

The periscope, projecting five feet above the conning tower, could not be raised or lowered.

The little craft was equipped with a gyro compass, a magnetic compass, radio (made in U.S.A.) and underwater sound gear. It was armed with two 18-inch torpedoes, and a demolition charge capable of converting the midget itself into a giant torpedo.

The two-man submarine was designed primarily for hit-and-run tactics, and its hazardous operational features seem to have been counter-balanced by the possibilities for its mass production. With considerable foresight the Japanese, in 1941, were building scores of midgets for defense of the home- land's beachheads.)

While the midgets at Pearl Harbor were generally regarded as minor novelties, the mothering I-boats in the waters off Oahu constituted a major menace to the assailed Pacific Fleet. The I-boats were submarines of the long-range reconnaissance type. The typical I-16 class had a surface displacement of 2,180 tons, and was 348 feet in length, with a 30-foot beam. With a total horsepower of 9,000, the boats attained a surface speed of around 22 knots. Eight 21-inch tubes gave them a firepower equal to that of all but the newest American submarines.

For a number of days these big submarines had been off Oahu in company with their midget brood. Reconnoitering, their periscopes spied on the approaches to Pearl Harbor, marking the movements of the American fleet. but midget-tending and scouting for Yamamoto's carrier force were only part of this squadron's mission. Its chief mission, revealed in a captured copy of the Japanese plan of operation, was concisely stated as follows:

"WILL OBSERVE AND ATTACK AMERICAN FLEET IN HAWAII AREA. WILL MAKE A SURPRISE ATTACK ON THE CHANNEL LEADING INTO PEARL HARBOR AND ATTEMPT TO CLOSE IT. IF THE ENEMY MOVES OUT TO FIGHT HE WILL BE PURSUED AND ATTACKED."

The menace of this deadly backfield deployed to trap any warship attempting to escape the harbor is obvious. Had the U.S. Pacific Fleet sortied under fire on the morning of December 7, many of its warships might have been sunk in water too deep for recovery.

From the above and foregoing detail, an interesting highlight emerges.

The war in the Pacific began as a contest between surface forces and submarines.

In this preliminary foray the eluded and deluded surface forces remained at a disadvantage. That they were American and the submarines were Japanese was a factor awaiting speedy revision. But a change of denominators did not alter the values in the submarine vs. surface-force equation.