Japanese long-range prewar strategy was
suddenly upset on the eve of the Pearl Harbor attack. An entirely new role for
submarines was hammered out. The new terms of war were not ideal for the submarine
force, although there had been several decades of painstaking development of
submarine materiel, personnel, institutions, and strategic and tactical
doctrines. In general, more than twenty submarines were to precede the carrier
strike force to Hawaiian waters and there check on possible U.S. fleet
movements. If warships were sighted, the submarines were to track, but not fire
on, the enemy warships until the start of the air strike. Thereafter, the
submarines were to lurk outside Pearl Harbor and between the Hawaiian Islands
and the U.S. mainland to attack any warships attempting to escape from the air
strike, to finish off any damaged ships trying to limp back to mainland ports,
and to prevent any reinforcements from reaching Oahu.
Japanese submarines in Hawaiian waters were
plagued by mishaps and failure. Naval planners anticipated that the nine
fleet-type submarines of the 3d Submarine Group would have the best chance to
attack the enemy. With their vantage point some forty miles from Pearl Harbor,
these submarines formed a dense line capable of concentrated attack on U.S.
warships off Oahu.
However, U.S. Navy antisubmarine warfare
(ASW) forces were effective against the Japanese in about the only good news
from Pearl Harbor on December 7. For example, I–68, some thirty miles from the
entrance to Pearl Harbor, came under heavy depth-charge attack and suffered
some damage. I–69, after launching an unsuccessful torpedo attack against a
cargo ship on the night of December 7, was near Barbers Point in southern Oahu
when it got caught in what the Japanese thought was an anti-submarine net.
(I–69 probably became entangled in a stray U.S. towline or a harmless drill
minefield used by U.S. Navy minesweepers for practice.) The submarine was also
heavily depth-charged. Captain Nobuki Nakaoka, commander of Submarine Division
12, on board I–69, recalled later that a depth-charge explosion under the hull
produced a very hard shock and the boat had to dive as deeply as possible.
Leaks were dangerous, and it was impossible to use the ejection pump at such
great depths. The Japanese sailors were determined to fight to the end, but
they also abhorred defeat. Thus, they armed demolition explosives before making
a final attempt to escape from their entanglement. At a depth of 250 feet (245
feet was this submarine’s safe maximum diving depdth), I– 69 slipped out of the
net by going full astern and blowing its main tanks. I–69 was lucky to escape
undetected on the surface after some forty hours of struggle.
Several other submarines of the 3d
Submarine Group were also depth charged and had little success. I–72, for
example, sank a small cargo vessel some 250 miles south of Oahu on December 8,
and I–75 made a similar claim 100 miles south of Kauai on December 17. Having caused
no damage to U.S. warships, plagued by failures and missed opportunities, the
remaining submarines of the group left Hawaiian waters on December 17 to return
to Kwajalein.
Some of these submarines later returned.
I–72, for example, left Kwajalein for Hawaiian waters on January 12, 1942.
After a few days of patrolling, I–72 sank oil tanker Neches (AO-5) south of
Niihau Island on January 23. The incident was not without consequence, for
Neches was the sole source of fuel at sea for aircraft carrier Lexington and
its escorts. Because no other tanker was available, Lexington’s plans to attack
Japanese forces on Wake Island were called off.
Some fourteen other Japanese submarines
continued to patrol in Hawaiian waters after the air strike on Pearl Harbor.
The three submarines assigned originally as an advance screening unit for the
Carrier Strike Force joined four ocean-cruising submarines of the 1st Submarine
Group to continue patrol operations in Hawaiian waters. Of these seven
submarines, I–9, the flag submarine of Rear Admiral Tsutomu Sato, Commander
Submarine Squadron 1, made a modest attack—it sank U.S. steamer SS Lahaina
(5,645 tons) several hundred miles northeast of Oahu on December 11. The seven
older ocean-cruising submarines of the 2d Submarine Group also continued
patrols in Hawaiian waters until January 11, 1942. The flag submarine, I–7,
launched its seaplane for a completely successful dawn reconnaissance flight to
Pearl Harbor on December 17, despite the tightened defenses of Pearl Harbor.
Thus the high command in Tokyo received a full report of the damage caused by
its air attack.
The failure of the I-boats in Hawaiian
waters in December resulted in part from directing operations from afar. The
commander of the Sixth Fleet (the submarine fleet), Vice Admiral Mitsumi
Shimizu, filled the air each night shortly before the attack on Pearl Harbor
with radio messages from Kwajalein to his submarines around the Hawaiian
Islands. Naval authorities in Hawaii were thus made aware of the number and, to
some extent, location of the Japanese submarines. Consequently, U.S. ships and
various merchantmen were routed carefully to avoid the Japanese submarine
menace.
Five ocean-cruising submarines, each with a
piggyback midget submarine Type A Target (Ko-hyoteki), did not become part of
the grand plan to attack U.S. forces until the fall of 1941. The five
submarines were on their assigned stations near the entrance to Pearl Harbor on
the night of December 6 (Hawaii time). Despite trouble with the gyro compass of
I–24’s two-man midget submarine, its commanding officer, Ensign Kazuo Sakamaki,
was determined to disembark in his little submarine as scheduled. In the end,
Sakamaki’s mission was a failure, and his little submarine drifted beyond
Diamond Head to become stranded on a reef near Bellows Army Air Field. He was
washed ashore unconscious and captured on December 8, 1941, as the first
prisoner of war; his stalwart crewman died in the heavy surf. The other four
midget submarines were more easily launched before dawn on the day of the air
attack, Nevertheless, almost no information was received from any of them after
they sortied. Only Lieutenant (junior grade) Masaji Yokoyama in I–16s midget
submarine sent a message—he reported, “Tora, tora, tora” (meaning surprise
attack succeeded), at 2241 hours on December 7. Thus Japanese submariners
believed that an explosion sighted near midnight was caused by a torpedo
launched from Yokoyama’s midget submarine. But this is not confirmed by U.S.
Navy evidence; moreover, it is obvious that the error-riddled operation was
poorly executed and that reports of success were often based on modest
evidence.
All five midget submarines were lost
despite the efforts of the parent submarines. The five large I-boats patrolled
the waters south of Oahu during the day of the air attack on Pearl Harbor; then
they shifted to the south of Lanai, which was the designated area for recovery
of the midget submarines. The area was searched in vain before the parent
submarines left Hawaiian waters en route to Kwajalein on the night of December
11. In January 1942, there were only four U.S. Navy fast heavy carriers in the
Pacific—Lexington (CV-2), Saratoga (CV-3), Yorktown (CV-5), and Enterprise
(CV-6). Hornet (CV-8) reached the Pacific in March, and Wasp (CV-7) arrived in
June. U.S. carrier strength in the Pacific was weakened considerably by the
temporary removal of Saratoga when I–6 badly damaged the big carrier in an
attack about two hundred seventy miles from Johnston Island on January 11. Samtoga
did not complete repairs in Bremerton, Washington, and get back into action in
the South Pacific until August 1942. Indeed, the strategic balance early in the
Pacific war remained precarious with the loss of Lexington in early May in the
Battle of the Coral Sea. A month later I–168 sank Yorktown and destroyer
Hammann, tied alongside the severely damaged carrier. The strategic balance of
carriers was barely maintained because the Japanese also suffered heavy losses
of aircraft carriers, particularly at Midway.
During this time, hundreds of U.S.
warships—including aircraft carriers Enterprise, Lexington, Saratoga, and
Yorktown and their cruiser and destroyer escorts—steamed in and out of Pearl
Harbor, but only Saratoga was hit by a Japanese submarine-launched torpedo. A
few minor cargo vessels were sunk and no warships. Otherwise, some night
bombardments of islands—Maui, Hawaii, and Kauai, for example—were carried out,
an indication that the submarines were about to conclude their patrols and
start homeward. (On an I-boat’s return to home port, a depleted supply of
deck-gun ammunition was viewed as evidence of warlike prowess.) None of these
bombardments caused much damage, and U.S. intelligence officers, who knew that
a bombardment was a fairly reliable indication that the submarine was departing
the area, used this information for routing ships, as already noted. Thus
Japanese submarines were a nuisance in Hawaiian waters, to be taken seriously,
but in their operations they pretty well unmasked themselves and caused no
strategic damage to the ability of the United States to respond to Japan’s
attack on U.S. territory.