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The Perils of

Technological

Transformation

A Case Study of

the Japanese Attack on

Pearl Harbor

Dr. Alan D. ZimmCDR USN (ret)

alan.zimm@jhuapl.edu

Pearl Harbor and the

Perils of Technological Transformation

• What can go wrong:

– Failure to view a new technology holistically

– Failure to accept or adapt to successful technology

– Reliance on faulty technological studies

• The bizarre world of testing

– Distrust of new technology

– Social consequences of new technology

• Authority, decisionmaking, changing power hierarchies

Shea's Law: “The ability to improve a design occurs primarily at the interfaces.

This is also the prime location for screwing it up.”

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A “Brilliant” Attack

• “brilliantly conceived and meticulously planned”

• “The attack was almost textbook perfect." • The plan was “bold and original.”• “The Japanese aerial attack was an unqualified success.”• “The attack plan was brilliant.” • “…like a flashing samurai word [the Japanese at Pearl Harbor] decapitated

the U.S. Fleet.”[4]

• Really?

#

Attack Potential

• 8 Battleships

• 8 Cruisers

• 40 Torpedoes

• 50 800-kg AP Bombs

• 81 250-kg GP Bombs

• 27 Torpedo hits

• 5 - 8 AP bomb hits

• 49 GP bomb hits

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Priority Targets

Expectations

Battleship

Cruiser

AP = Armor Piercing

GP = General Purpose

Weapons

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Attack Potential

• Torpedo hits: 4 to sink BB

2 to sink CA/CL

• AP bomb hits: 43% per bomb hit v. BB

• GP bomb hits: 4 to sink cruiser

• 4 BB, 4 Cruisers inaccessible to torpedoes

• With perfect fire distribution, expected value of attack =

4 BB torpedoed, 2 BB sunk / crippled by bombs, 8 cruisers sunk

14 of 16 targets destroyed or crippled

PLUS 11 torpedo hits & 17 GP bomb hits “overkill”

(1/3rd more hits than needed: 3 BB + 4 cruisers, 21 targets total)

BB = Battleship

CV = Carrier

CA / CL = heavy or light cruiser

AP – Armor Piercing

GP = General Purpose

Expected

Hits:

27

5

49

Hits to Kill

Meager Results

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5 targets sunk

(Killing ordnance

on only 3 targets)

1 (Nevada) sunk due to damage

control error

1 (California) sunk after ship

was abandoned due to burning

oil

Attack achieved

20%of its potential

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Prior to the Attack on Pearl Harbor:

Japanese Technological Advances

• Mass employment of carriers

– Command and Control and Aircraft Radios

• Aerial Torpedo Warheads

– Defeating BB underwater protection

• Bombsights

– Precision attack dive bombers

– High altitude level bombers

• Armor Piercing (AP) bombs

– Penetration of armor - Testing

– Fuzing and manufacturing

• General Purpose (GP) Bombs

– Fuzing and Manufacturing

• A6M Zero – high performance fighter

Much of the Japanese

poor performance at Pearl

Harbor came from poor

assimilation of new

technology

As

Planned

IP

North

South

SURPRISE:Fighter lead to “seize

control of the air”

Torpedo bombers descend,

head for IP

Dive Bombers orbit, delay

17 November 1941

• Admiral Yamamoto on board Akagi:

• “Although we hope to achieve surprise, everyone should be prepared for terrific American resistance … in this operation we will meet the strongest and most resourceful opponent of all.”

• Japanese preparations and training

were all based on surprise.

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Meeting while at Sea

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CDR Genda

First Air Fleet Air Officer

Lead Planner

CDR Fuchida

Commander of the

first wave

Planner

LCDR Murata

Leader of the torpedo

bombers

Two plans

• One flare: Surprise

– Torpedo bombers lead

– Fighters offensive counter-air

– Dive Bombers wait to hit Ford Island

• Two flares: No Surprise

– Dive Bombers “distract” AA by attacking Ford Island

– Torpedo bombers attack close behind

• Murata Overruled

• Japanese application of bakuryo

– “officers behind the curtains”

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Fuchida’s Tale

• “[Fuchida] fired a single Black Dragon [flare]. Murata saw it and

swung low toward the target. But Lieutenant Masaharu Suginami,

a fighter-group leader, kept his aircraft in cruise position. Thinking

he had missed the first [flare], Fuchida fired another. Then he

groaned – Takahashi, mistaking the second [flare] for the

double signal … swooped in with his dive-bombers. Fuchida

ground his teeth in range. Soon, however, he realized that the error

made no practical difference.”• Prange, Goldstein, Dillon. God’s Samurai: Lead Pilot at Pearl Harbor Page 34.

• “That blockhead Takahashi”

– Killed at the Coral Sea

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Approach to Target

Strategic Bombing Survey Chart

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Decision to use

FLARES to

communicate

Approach to Target

Later Testimony from Veterans

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Dive Bombers

depart first

Torpedo Bombers

depart

Torpedo bombers

loose formation,

extended

intervals,

no fighters,

some get lost

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C2 Issues: Deconfliction

CV Group (16 Kate) briefed profiles

BB Group (24 Kate) briefed profiles

North

Radio to the Rescue?

Japanese Radio Innovation

• 1940 – Capability to install radios in aircraft

• Full fleet installation by late 1941– Installation problems

Captured A6M Zero.

Note position of pilot’s head

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Comparison Cockpits

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USN F4-F “Wildcat” German FW-190 “Shrike”

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Japanese Radio Innovation

• 1940 – Capability to install radios in aircraft

• Full fleet installation by late 1941– Installation problems

Captured A6M Zero.

Note position of pilot’s head

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A6M Zero Cockpit Installation

Soryu 8Nagai

Mori

Tadashi

Kimura

Nakajima

Fujiwara

Sato

Kawashima

Hiryu 8Matsumura

Oku

Yanigimoto

Urata

Takahashi

Kasajima

Kadono

Sugimoto

Akagi 12Murata

Murakami

Katsuki

Goto

Ikumoto

Yasue

Negish

Kaido

Hanai

Suzuki

Tateyama

Goto

Kaga 12Kitajima

Yoshikawa

inknown

Sato

Nakagawa

Kitahara

Suzuki

Tanaka

Kumamoto

Iwata

Ohashi

Nagai

Time ~0755 ~0756 ~0757

Attack CV anchorage

Attack CV anchorage

Attack Battleship Row

Attack Battleship Row

= Formation Change

= Attack

Time – Event Plot

Japanese Torpedo Attack

Time

Soryu 8Nagai

Mori

Tadashi

Kimura

Nakajima

Fujiwara

Sato

Kawashima Nagai, Mori

reject Utah

Nakajima,

S6, S7, S8

detach to

attack Utah S3, S4 join

Nakajima

6 attack Utah;

2 hits on Utah

1 Hit Raleigh

Nagai attacks

Helena

Mori aborts

v. HelenaHiryu 8

Matsumura

Oku

Yanigimoto

Urata

Takahashi

Kasajima

Kadono

Sugimoto

Kadono, Sugimoto,

Yanigimoto, Urata,

Takahashi, Kasajima

miss turn, orbit Ewa

Matsumura, Oku

turn south

Kadono sees

Nagai attack,

all turn to

attack HelenaMori attacks

CA mixed w/

Kaga groupMatsumura, Oku

target BBRow

4 attack

Helena

Kadono, Sugimoto

see Mori abort

Akagi 12Murata

Murakami

Katsuki

Goto

Ikumoto

Yasue

Negishi

Kaido

Hanai

Suzuki

Tateyama

Goto

Kaga 12Kitajima

Yoshikawa

inknown

Sato

Nakagawa

Kitahara x

Suzuki x

Tanaka

Kumamoto x

Iwata

Ohashi x

Nagai x

Murata and

Goto’s shotais

keep together

500 meter

intervals

6 A/C strung out

~ 1500-1800

meter intervals

12 Kaga A/C

strung out

~ 1500-1800

meter intervals,

Trail Akagi A/C

by 3 miles

Soryu 8 Hiryu 8Claims

6 BB basket mast

3 BB

2 BB

3 heavy cruiser

Katsuki and Yasue

nearly collide; Yasue

torpedo jettisoned

Target OK and WV

Mori sees

Hanai

attack BB

Row

Mori aborts

v. CA

Matsumora aborts due

to Suzuki propwash

Oku attacks WV

Go around, join

end of Akagi’s

string

Kitahara (jettison,

shot down), Ohashi

shot down, Nagai

(jettison) shot down,

Suzuki blown upKumamoto

blocked by

Mori,

attacks NV

Shot

down

~0755 - 0757~0810

~0809

11 Akagi attack

BBRow

7 Kaga attack

WV, OK

Akagi 12Claims

11 hits on 3 BB

Kaga 12Claims

8 hits on 2 BB

Underway claims reports from Rengo Kantai

~0757

~0759

~0802

Hanai hit, possible go-around

Attack

WV

2 attack OK

As Executed

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Japanese Torpedo Attacks#

6

3

5

1

9

12

Technology to Sink a Battleship

Technology: Offense v. Defense

• Torpedo defense:• Outer hull

• Four torpedo bulkheads

• Alternate air- and liquid-filled

voids

• Inner holding bulkhead

• Are Japanese aerial

torpedoes powerful enough?

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New Mexico-class cross section

Plate thicknesses in millimeters, 25.4mm = 1 inch

356 = 14” 152 = 6” 63 = 2.5”

51 = 2” 38 = 1.5” 19 = .75”

Tosa Full-Scale Destructive Tests

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Actual Torpedo Damage

• No inner holding bulkheads were

breached

What Went Wrong?• Subscale experimental errors

• Calculated “fudge factors” off

• Assumption regarding voids

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Nevada

California

West Virginia

Tosa

Lessons for Historians: Tech Reports cannot always be trusted

Assumptions Drive Results

Technology Advance: Bomb Sights

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Course Setting Bomb Sight

(CSBS1 - Japan)

Norden(“Hit a pickle barrel from 30,000 feet”)

Japanese v. US Bomb Sights

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CSBS Norden

Pearl Harbor

49 Bombs:

10-14 hits(4 on collateral targets)

Midway

291 Bombs

0 hits

Technology Advance: Armor Piercing Bomb

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•1940 - No AP bombs

available

•Converted 41cm AP shellsNagato-class BB

•Exceeded max payload

• Shaved off ~ 181 KG

(400#)

•Tested by dropping

against armor plates from

4,000 and 3,000 meters

altitude

Technology Advance: Armor Piercing Bomb

• 10 confirmed hits

• 6 duds, malfunctions, or low-

order detonations – Dreadful!

– 2 Penetrated turret tops at seams

– Several broke up on entry

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Bomb hits armor at seam

Rear of bomb slaps armor plate,

weakened section shatters

73

deg

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•250-kg General Purpose bomb,

0.2 second delay fuze (“carrier killer”)

•Facts:

•Bomb & Hit counts

•Witness reports

•Evaluation:

•high dud / Malfunction rate

•Causality:

•poor manufacturing and testing

•Suggests poor manufacturing and

testing

Technology Advance: General Purpose Bombs +

D3A “Val” Dive Bomber

Facts, Events,

Sequence

Evaluation and

Analysis

Causality

Gap: Weapons-to-Target Matching250-kg GP bomb crater, 0.2-sec fuze, Ford Island Dispensary

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Poor Weapons-to-Target Match550-pound GP bomb crater, 0.2-sec fuze, Wheeler Field

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Bomb achieved 6-25% of superquick fuzed weapon

Technology Advance:

Dive Bomber Bombsights, Command and Control

• D3A “Val” dive bomber

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Type 96 Sight Sight Picture

Dive Bombing Tactics, Techniques, and Procedures

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60-degree

dive

Sight on top

of mainmast

30-45 second intervals

Following bombers

adjust aimpoint

based on leader’s fall

of bomb3,000

meters

altitude

initiate

dive

Sight Picture

Splash

Adjust

Japanese achieved

60-80% hits during

training

Later, up to 90% under

combat conditions

Poor Performance

• Japanese expected 49 hits

• Hit what was aimed at: 9 hits– 12%

– Only one hit on cruiser

– 6 “collateral damage” hits

• DD Cassin and DD Downes: 3

• DD Shaw: 3

• Not one hit of strategic

importance

• QUESTIONS

– Why so few hits?

– Why did the attack take so long?

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Time Magazine Pearl Harbor Photograph

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90% Cloud Cover at 3,500 to 5,000 feet

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Cloud Cover

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Dive Bombing Tactics, Techniques, and Procedures

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60-degree

dive

Sight on top

of mainmast

30-45 second intervals

Following bombers

adjust aimpoint

based on leader’s fall

of bomb

Sight Picture

Splash

Adjust

10,000 meters

altitude

Dive Bombing Tactics, Techniques, and Procedures

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60-degree

dive

Sight on top

of mainmast

30-45 second intervals

Following bombers

adjust aimpoint

based on leader’s fall

of bomb

This technique

doesn’t work with a

1,000 meter cloud

deck!

Sight Picture

Splash

Adjust

10,000 meters

altitude

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3 Dale

3 Dobbin

6 Curtiss

8 Shaw

9 Pennsylvania

3 Raleigh

4 Helena

3 California

10 Navy Yard

5 Tangier

2 Helm

1 Solace

1 Aylwin0840 – 0920, 7 Dec 1941

Outside entrance

buoy

Dive Bomber Attacks # Target

Nevada14 Nevada

Dale2 Dale

2 Neosho

1 Pyro

Cruiser targets

Results: far less than Potential

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5 targets sunk

Killing ordnance

on only 3 targets

2 by Torpedoes, 1 by AP bomb

1 (Nevada) sunk due to damage

control error

1 (California) sunk after ship was

abandoned due to burning oil

78 Dive bombers

made no substantive

contribution

Attack directly achieved

20% of expectations

15% compared to

capacity

Lessons

Introducing a new technology does not guarantee

proper employment Doesn’t guarantee people will even think about how to best use it

New technology may require (or lead to) new

approaches

Human Proclivities trump technology!

You have to convince them on the deck plate/cockpit

level

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Stump the Chump Time

Questions?

Someone in the

audience has the

question that will

prove that the

speaker is a

Bloody

Idiot

Just quit actin’ like a

know-it-all and

answer the dam’

questions, OK?

Good Reads

• Prange, Goldstein, Dillon. At Dawn We Slept– Standard, Comprehensive Account

• Prange, Goldstein, Dillon. Pearl Harbor: the Verdict

of History– Excellent analysis

• Prange, Goldstein, Dillon. God’s Samurai– Biography of Fuchida. Does not include recent research

• Prange, Goldstein, Dillon. The Pearl Harbor Papers– Some dry documents but also first person accounts

• Walter Lord. Day of Infamy– Readable account

• Michael Slackman. Target: Pearl Harbor

• Daniel Madsen. Resurrection: Salvaging the Battle

Fleet at Pearl Harbor

• Mitsuo Fuchida. For that one Day– Memoire – but with exaggerations and limited truthfulness

• Kinoaki Matsuo. How Japan Plans to Win– Japanese intel officer, translation of 1940 book

• Lambert and Polmar: Defenseless– Excellent assessment of US air defenses before the attack

• Ron Werneth. Beyond Pearl Harbor– Accounts from surviving Japanese aviators, many post PH

• Paul Stillwell. Air raid: Pearl Harbor!– Recollections of a day of infamy

• Burl Burlingame. Advance Force Pearl Harbor– Japanese submarine deployment

• Roberta Wohlstetter. Pearl Harbor warning and

Decision– Good information, a bit of a slog to read

• Some Supplemental Reading:

• Akira Yoshimura. Build the Musashi– Full of insights on the Japanese approach to naval warfare,

technology, culture, carriers v. battleships

• Akira Yoshimura. Zero Fighter– New Zeros being towed by water buffalo

• Evans and Peattie: Kaigun: strategy, Tactics, and

Technology in the Imperial Japanese Navy, 1887 –

1941

• Evans and Peattie. Sunburst: the Rise of Japanese

Naval Air Power, 1909 – 1941.

• John Stephan. Hawaii Under the Rising Sun:

Japan’s Plans for Conquest after Pearl Harbor.

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