Reassessing

The

Combat Performance

Of The

Japanese Midget Submarine Force

At

Pearl Harbor

A Technical Assessment

I-22 Tou

I-16 Tou

Mother Submarine & Midget Release at Local Time

(0626 Sunrise)

Bearing & Range from Pearl Harbor’s

Buoy marking the channel entrance.

I-16 and I-16 tou (A) 0042 212 Degrees at 7 Nautical Miles

I-22 and I-22 tou (B) 0116 171 Degrees at 9 Nautical Miles

I-18 and I-18 tou (E) 0215 150 Degrees at 12.6 Nautical Miles

I-20 and I-20 tou (D) 0257 151 Degrees at 5.6 Nautical Miles

I-24 and I-24 tou (C) 0333 202 Degrees at 10.5 Nautical Miles

Release Sequence

I-16 Tou

I-22 Tou

I-18 Tou

I-20 TouI-24 Tou

0000 15 30 45 0100 15 30 45 0200 15 30 45 0300 15 30 45 0400 15 30 45 0500 15 30 45 0600 15 30 45 0700 15 30

I-16 tou ^----------------------------*-->

0042 0215 30

I-22 tou ^----------------------------------*--->

0116 0317 35

I-18 tou ^---------------------------------------------*---->

0215 0455 12

I-20 tou ^----------------- --*---->

0257 0409 24

I-24 tou ^ Defective Gyro----------------------------X------------------>

0333 0613

USS Condor & USS Crossbill []--------------------------{}----------------------------+

0200 0350 0525

USS Antares -------------------------->

USS Ward -------------------------------------------------------------------------------------------------------------------{}--X---------->

0630 45

Submarine Net Gates Open 0200* 0458----------------------------------------->

^ = Release Times

* = Estimated Time to Harbor Entrance Channel Buoy @ 5 Knots

> = Estimated Time to Harbor Entrance Channel Buoy @ 4 Knots

X - I-24 tou Runs Aground On North Shore

[] - USS Condor On Station For Mine Sweeping Ops

{} - ~ Time That USS Ward Sights One Of The Midgets

X - USS Ward Open Fires on One Of The Midgets

* - Exact Time For Nets Opening Unknown. However, At 0200 The Minesweepers Passed Through

MIDGET SUBMARINE MOVEMENT / USN EVENT AND CONTACT TIMELINE

Midget Attack Geometry

Midget Attack Geometry

The Initial Study - 1993/94

NPS Asked, “Is It A Sub”?

Team Conducted Two Interrelated Analyses:1 - Imagery Intelligence:

Look for Observables

Establish Timeline

2 - Photogrammetric: Conduct Critical MeasurementsCorrelate Object to Geographic Location

Determine Object’s Dimensions

1993-94

Object

Roster

Tails

Splash

Points

Wave

Propagation

Plume

Torpedo

Tracks

Utility

Boat

Splash

Point?

Aerial Photography 26 November 41

~21.21.34N/157.57.18W

Wave Motion

Entrained Water

Submarine Trim

SUBMARINE TRIM ALTERED

1994 Summary of Analysis:

Team’s Assessment:

Established Operational Timeline

Measurements

Rooster Tails

Wave Propagation

Torpedo Tracks v. Splash Points

Explosion Plume coincides with TT

Report To NPS 6 Dec 1994 - SUBMARINE

Subsequent Analysis - 1998

Forensic AnalysisRoster Tails

Weapon Effects

Entrained Water

Submarine Trim

APPEARANCE DIFFERENT FROM EXPLOSIONS

ENTRAINED WATER FROM COUNTER-ROTATING

PROPELLERS

Weapons Effects 2

Weapons Effect

Cavitation Regions For Underwater Explosions

UNSOLVED HISTORY SERIES COLLABORATION

2002-2003

2000 & Beyond: Correlation Of Additional Data

Translated Official Records

Analyzed Collateral Images

Translation Of Official Records

From Japanese Defense Force Documents*At 2241, December 7 (Local Time)

To I-16 From I-16 tou

“I Succeeded In A Sneak Attack”

At 0051, December 8 (Local Time)

To I-16 From I-16 tou

“Impossible To Navigate”

•As provided by Yoshinori Nakai, Washington Bureau Chief, Manichi Newspapers

•Translated by Yoko Spalding, Quick-Call Decision Interpretation, Inc.

WHAT WE KNOW

Of the Five Submarines:

I-22 Tou 7 Dec 41

I-18 Tou 2005I-20 Tou 1960

I-24 Tou 7 Dec 41

THE BIG QUESTION: WHERE IS I-16 Tou?

JOURNEY PROGRESSION

1993 – Is It A Sub?

1994 – Submitted Findings To The NPS

1998 – Subsequent Analysis Applied

1999 – Submitted Findings To USNI

2000 – Cross Correlation Of Additional Data

2004 - Discovery TV Correlates Assessment

2010 - NOVA’s Portrayal Clarifies Assessment

Where is the Sub?

NOVA Assessment:

• Midget Sub recovered after Disaster

• Wreckage dumped offshore• Photographic Evidence Of Wreck• Crew Scuttled Sub in West Loch

HOWEVER: Appearance Does Not Correlate

Edges not caused by internal explosion

Skin peeled outward