Special Operation Research Group Summary of US Submarine Attacks in WW II

During WW II the Submarine Operations Research Group (SORG), under Commander Submarines, Pacific (ComSubPac), listed and assessed all reported submarine attacks. It took into account the commanding officers' patrol reports (the primary source of data on most attacks), the comments of higher commanders in their endorsements to the reports, and the limited information available from radio traffic with submarines that were lost or other sources. SORG tabulations by date and hour of attack are in the spreadsheet, but also reports by boat and patrol number were created (available on this web site). SORG data were classified SECRET until March, 1972. Little other intelligence information was made available to SORG in accessing the attacks. ULTRA information obtained from decrypted Japanese messages was not provided to SORG (declassified in the 1990's).

Data entries in the SORG spreadsheet are: date (month/day/year), hour, light condition, operational command (headquarters), latitude, longitude, type of approach and attack, torpedo model, torpedoes fired, hits, target type, result, estimated target tonnage, submarine hull number, and patrol number. In spreadsheet format sorting the data by any data column can be done.

The "result" data represents SORG's assessment of the success of the attack with, in most cases, no knowledge of the identity of the actual target. SORG's assessments of sinking or damage, as well as target tonnage, almost always agree with those of the operational commanders. Unfortunately, both are greatly overestimated in comparison with postwar analyses. Although this was already known during the war to the few people who had knowledge of ULTRA findings, it was not revealed lest the Japanese find out that their codes were being broken. The SORG assessments, however, have been given certain credence by being cited in the U.S. government publication "United States Submarine Losses, World War II."

Despite its limitations, the SORG compilation is a generally accurate summary of the data in patrol reports; as such it is handier to work with than the original patrol reports. In addition to the ULTRA problem, SORG's assignment of partial credit to two or more submarines in certain cases has proven to be incorrect. Another shortcoming is that SORG gives the time of attack rounded off to the nearest hour, and more seriously, shows the time as given in the patrol report without consideration of the zone time being used. Since Japanese reports all used Tokyo time, submarine time reported in a different zone must be corrected before the reports can be compared. Entries with known typing errors by SORG end with an "*" in the cell.

Download subreports-sorg.xls

Key to SORG Data Entries

D-Dutch Harbor
P-Pearl Harbor
T-Two Commands
P-Sunk - Partial Credit
O-No Damage
Blank - Not Final Attack on Target

Type Approach and Attack:
Day Night Twilight Unknown
Visual, Surfaced B S K 2
Periscope, Surfaced C T L 3
Radar, Surfaced D U M 4
Sound, Surfaced E V N 5
Periscope, Submerged G X P 7
Radar, Submerged H Y Q 8
Sound, Submerged I Z R 9
Unknown & O O Blank

Enemy Group Type:
A-Independent merchant vessel (over 499 tons)
B-Group of M/Vs not escorted by surface craft (over 499 tons)
E-M/V(s) with surface escort (over 499 tons)
L-Independent combatant
M-Group of combatants not escorted by surface craft
W-Craft less than 500 tons not on patrol duty (escorted or not)
Y-Hospital Ships (without other M/Vs - escorted or not)

First Contact:

Submerged Surfaced Unknown
Lookout None A None
Periscope K B 2
Radar L C 3
Heard Enemy Pinging N E 5
Other or Unknown Sound M D 4
Unknown O & -

1-Submerged one minute or less
2-Submerged over one minute
SUB-Submerged Attack
SUR-Surfaced Attack
D-Depth Charge or Bomb
Type of Attacker:
SC-Surface Craft

F-Accompanying Fleet Action
G-Group Offensive
O-Independent Offensive
S-Special Mission
V-Lifeguard Duty
How Detected:
E-Echo Ranging
H-Attacker homed by other enemy units
S-Counterattack followed salvo, no other means determinable
Time Relative to Salvo: (Time of Detection)
B-Before own salvo fired
A-After own salvo fired
P-Detection prevented own salvo
O-No associated salvo

0-None or none stated
1-Slight (cork, paint, light bulbs, etc.)
2-Embarrassing (important but fragile equipment-repairs take only a few hours)
3-Moderate (hampers operations, affects safety, repairs take more than a few hours)
4-Severe (causing shortening of patrol)

A comprehensive accounting of all U.S. and allied (British, Dutch, and Soviet) submarine attacks on the Japanese for which success was claimed or occurred has been painstakingly compiled in "United States and Allied Submarine Successes in the Pacific and Far East During World War II - Fourth Edition" by John D. Alden and Craig R. McDonald. The data greatly expands upon the SORG data by using ULTRA messages now declassified, and recently translated Japanese documents that provide correct Japanese ship names, ship type and tonnage, convoy names, human loss numbers and other attack details, as well as an evaluation of the claimed success of each attack. The book is available from the publisher (www.mcfarlandpub.com).

We thank Craig R. McDonald and John D. Alden for their generous donation of the digital copy of the SORG raw data.

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