Attack on Pearl Harbor (23 page)

Royal Oak
was an old ship, an “R” class laid down in 1914 under lesser standards for anti-torpedo protection. Italian Navy crews did not have a good reputation for damage control. From these examples the Japanese would have concluded that four hits on a battleship would be sufficient to achieve their objective. With potentially eight battleship targets, and assuming 80% hits, five aircraft should attack each battleship. This would require all 40 torpedo bombers.

The Japanese received specific reports on where the battleships were moored, and knew that only four battleships were positioned where they could be hit by torpedoes. There were four additional ships within their targeting instructions and accessible to torpedoes.
Phoenix
, a modern 10,000 ton cruiser, was anchored in the East Loch astern of
Nevada
; a sister ship,
Helena
, was moored at 1010 Dock;
Raleigh
and
Detroit
were at the carrier moorings. Four other cruisers were at the Navy Yard piers, but
New Orleans
,
San Francisco
,
St. Louis
, and
Honolulu
were inaccessible to torpedo attack.

Adding the accessible cruisers to the four outboard battleships gives eight valid torpedo targets within the Japanese prioritization instructions. An even distribution would have put five torpedo bombers against each target; a better distribution would be four against each cruiser and six against each battleship. A 50% hit rate would have likely sunk the four cruisers and sunk or crippled all the battleships. This would have more than doubled the returns for the torpedo bombers over what was actually achieved.

The original Japanese plan had 24 torpedo bombers directed against Battleship Row. Evenly distributed, this would allocate 6 bombers against each vulnerable battleship; an 82.5% hit rate (as achieved in the last practice session) would give five hits per battleship.

The second group of 16 bombers had 13 potential attack paths against ships at the carrier moorings northwest of Ford Island, cruisers anchored in the East Loch, and two potential paths of approach directed against ships pierside at 1010 dock at the Navy Yard.
⁹
Had they gone for the cruisers, as would be logical under their prioritization scheme, there would have been four torpedo bombers per cruiser, enough to sink them all even with a 50% hit rate.

Mental Errors and Physical Errors

In sports such as football and baseball there are mental errors and physical errors. The same holds true in battle: there are bad decisions, mental errors, and physical errors, such as poor execution in aiming and firing. The torpedo bombers committed both types of errors.

The first significant mental error was committed by the torpedo bombers assigned to attack the carrier moorings. These moorings were occupied by
Utah
, an aged demilitarized battleship serving as a target ship, two early-’20s-era cruisers
Raleigh
and
Detroit
, and
Tangier
, a former cargo ship converted to an 11,760-ton seaplane tender. The obsolescent cruisers were legitimate targets on the priority list, although not very glamorous;
Utah
was a clear waste of ordnance.

John Toland relates the story of Lieutenant Matsumura, leading
Hiryu’s
torpedo group, as he approached Pearl Harbor:

Mori, flying on Nagai’s wing, also observed this attack. “Can’t they see that two of the ships are nothing but cruisers? It would be a crime to waste torpedoes on them when the battleships are right there in sight a bit further on.” Mori was determined to use his torpedo on nothing less than a battleship,
¹¹
an attitude shared by all the Japanese aviators.

Regardless of warnings, six of the torpedo bombers attacked
Utah
, four of them after breaking away from their
shotai
leader. One torpedo missed so badly it hit
Raleigh
.
Raleigh
nearly capsized, forestalled by prompt damage control.
¹²

This waste of torpedoes can fundamentally be blamed on the planners. Word had been received that there were no carriers in Pearl Harbor. They let stand the attack on the carrier moorings hoping a carrier might return, a hope that ended up wasting six torpedoes.

Their hope did come close to being fulfilled;
Enterprise
would have arrived on Saturday but was held up by bad weather. But a bad decision should not be considered good just because fortune intervenes. The fact remains that the planners left no provision to change the plan to react to updated intelligence.

Toland stated that
Utah
was misidentified as a carrier, an assertion that has been echoed by other historians.
¹³
Comparing the silhouettes of
Utah
with
Enterprise
(or any other carrier) makes this hard to accept. Photographs of
Utah
capsizing show that her decks “stripped and covered with planks” did not make for a carrier silhouette. Japanese veterans stated that
Utah
was actually misidentified as an operational battleship.

The first physical errors are apparent. Of six torpedoes launched against
Utah
, only two hit their target. One hit
Raleigh
in the adjacent berth. One torpedo slid up a muddy beach onto Ford Island. The other two are buried in the harbor bottom. These bombers were unopposed by AA fire and had an easy approach path to their targets, virtually training conditions. They should have achieved the training level of success, five hits instead of two.

In the absence of carriers,
Soryu
’s and
Hiryu
’s torpedo bombers were to search out and strike alternate targets. Matsumura related:

Another five aircraft attacked the 1010 Dock mooring occupied by an antiquated minelayer outboard of a modern light cruiser, a puzzling silhouette when backlit by the rising sun. The light cruiser
Helena
was a legitimate target on the priority list; however, it was not so important a target as to justify five torpedoes. The attackers saw in the confused silhouette what they wanted to see, a battleship, a common occurrence under the stress of combat.

One torpedo passed under minelayer
Oglala
to explode against
Helena
. The blast split the seams of the WWI-era minelayer, which slowly filled with water and eventually capsized.
Oglala
was eventually salvaged, but with difficulty—she was raised and sank three times before she could be towed into drydock. This was done not because she was a valuable ship, but because her sunken hull blocked one of the most valuable berths in the harbor.

Three of the torpedoes hit bottom. A photograph shows what might be the froth from the engines of two torpedoes stuck in the mud near the channel dredge, along the attack path leading to
Helena
.
¹⁴

The remainder of
Soryu
’s and
Hiryu
’s torpedo bombers attacked battleships; most went for
Oklahoma
or
West Virginia
, the recipients of more than their fair share of torpedoes.

The reason why
Oklahoma
and
West Virginia
were disproportionately targeted is apparent from the chart. The approach to these ships was the easiest, a straight 1,000-yard run, flying along the Southeast Loch past the Navy Yard waterfront. In contrast, the approaches to
Nevada
and
Arizona
, shown on Fuchida’s chart, involved skimming over the Kuahua Supply Base. After clearing the turbulence generated off the fuel tanks, and the alternating sink and lift generated by alternating bands of land and water followed by another band of turbulence from the supply base buildings, the pilot would have about 6 seconds to throttle back, descend, establish launch parameters in speed, altitude, and attitude, and release their torpedo. These routes were impossible, and all the pilots had the good sense to avoid them.

The alternative was to take the same route down the Southeast Loch on a course of about 300 degrees, and then, when near the junction with the main channel, rack the aircraft into an 80-degree right turn and release the torpedo on a course of about 020 degrees. That turn, at slow speed in a heavily loaded aircraft at an altitude of less than 60 feet, would be dangerous. The aim would have to be precise, as the targets would be foreshortened by the angle on the bow.

This approach was selected by probably only one or two aircraft:
Lessons
praises those aircraft that, “realizing just prior to charging [firing] torpedoes that they were aiming at the wrong target, made bold turnings to the right targets amid fierce gunfire.”
¹⁵
It is no wonder that
Nevada
was hit by only one torpedo, and
Arizona
none.

The attack approach against
California
would be easier, but from the drop point the target angle against the ship was about 45 degrees off the port quarter, presenting a foreshortened target. One torpedo bomber, in a spectacular display of airmanship, approached from the south along the main channel, cleared the Navy Yard, angled to the left to line up the attack and dropped off the ship’s bow, scoring a hit.

Attack Routes and Deconfliction

An orderly attack was not achieved. The deconfliction plan, to have all aircraft make a left turn after dropping, was not always executed. Routes were blocked by AA fire and smoke. Formations became intermixed, runs were aborted, re-run, aborted again.

In postwar interviews the aviators did not mention target prioritization; rather, they spoke of unexpectedly heavy AA fire, the difficulty of identifying targets, and their desire to get their torpedo into a battleship, any battleship. Only the most experienced and steady aviators thought of spreading the attack. What the planners saw as a simple task just could not happen under combat conditions. The fact that an attack planned to take two minutes actually took 11 to 15 is an indication of the severity of the problem.

Overkill

Fuchida’s 27 December 1941 map used to brief Emperor Hirohito shows 36 torpedo hits. Twenty-one were on
Oklahoma
and
West Virginia
, twice as many as needed. Five were on
Helena
, over 100% overkill, and six on
Utah
, all a waste. Thus, from Fuchida’s own report, 19 of 36 torpedoes (53%) were either overkill or wasted. Fuchida’s expressed desire to concentrate and bag at least one battleship may have been reflected in the concentration of fire, if only subconsciously.

Another consideration comes from the viewpoint of the torpedo bomber pilots. Attacking at 20- to 30-second intervals, aircraft might only see a few previous torpedo plumes, if they registered any at all due to target fixation and tunnel vision. They would not have information regarding the total number of hits a given battleship had absorbed prior to their attack. The photographs attest that after a plume subsided, there were few clues to guide the later torpedo bomber pilots to facilitate a weapons distribution decision. An aircraft, seeing plumes on
Oklahoma
, would shift to the next easiest target,
West Virginia
. After a few hits on
West Virginia
, the plumes on
Oklahoma
would have subsided, inviting additional torpedoes to be directed at
Oklahoma
. The 70-second gap between the
Akagi
and
Kaga
attackers made the problem harder.

To properly distribute their torpedoes under a prioritization scheme, the aircrews needed more information beyond that which they could collect with their own eyes. Otherwise, the harrowing approach would invite repeated hits on the easiest target. This occurred in the rehearsals and was not corrected.

Lessons
acknowledged “there were over concentrations of attacks and also some gaps which had not been damaged.” They attributed this to a number of reasons, including “errors in identifying ships in the aircraft reconnaissance report,” a somewhat odd notion, and perhaps a typically oblique Japanese reference to the torpedoes wasted against
Utah
.
Lessons
also blamed poor visibility caused by the smoke from burning aircraft on Ford Island. This could be attributed to Fuchida’s error with the flare guns if it were true; however, the wind blew the smoke from Ford Island to the southwest, away from all the torpedo attack routes, so it is hard to see how smoke would have interfered with the attacks on Battleship Row. Photographs show Battleship Row clear of smoke until
Arizona
exploded, which occurred after the torpedo attacks had been delivered.

Lessons
also mentions that pilots could not evaluate the damage done by preceding torpedoes before launching theirs, and a concern that aircraft might run into the water columns from exploding torpedoes.