REFERENCE DOCUMENTS & RESOURCES - OFFICIAL ADMIRALTY DOCUMENTS
ADM 239/268: C.B.04039, ARMOUR PROTECTION (1939)
Updated 18-Oct-2007

This document is a modern transcription of Admiralty record ADM 239/268. It addresses armour protection of various Royal Navy and foreign ships. The original file is held at the The National Archives at Kew, London. This Crown Copyrighted material is reproduced here by kind permission of The National Archives.

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START OF TRANSCRIPTION

CONTENTS

__________

Page
Introduction
 
Table No.
1  Armour—British Ships
2   Armour—Foreign Ships
3   Range for Perforation of Deck Armour
4A   Perforation Range for Thickness of Vertical Armour in inches—90° inclination
4B   Perforation Range for Thickness of Vertical Armour in inches—60° inclination
5   British Capital Ships—Approximate Immunity Ranges to Chance Vital Hits in Magazines and Speed Hits in Machinery Spaces from Foreign Capital Ships' Gunfire
6   Foreign Capital Ships—Approximate Immunity Ranges to Chance Vital Hits in Magazines and Speed Hits in Machinery Spaces from British Capital Ships' Gunfire
7   British Cruisers—Approximate Immunity Ranges to Chance Vital Hits in Magazines and Speed Hits in Machinery Spaces from various Calibres of Guns
8   Foreign Cruisers—Approximate Immunity Ranges to Chance Vital Hits in Magazines and Speed Hits in Machinery Spaces from various Calibres of Guns

5

INTRODUCTION

__________

    This pamphlet is designed as a rough guide to the relative protection afforded by the armour of British and foreign capital ships and cruisers against gunfire from various calibres of guns.

    The information contained herein should be treated with caution. It is based on the assumption that the penetrative power of foreign shells and the resistance of foreign armour to shell perforation are the same as the British. Calculations of the maximum or minimum ranges at which perforation of armour takes place have been based on the most recent information available at the time of publication of this pamphlet.

    (ii) Knowledge of foreign armour is, in the case of certain countries, extremely scanty. In Table No. 2, which indicates the probable armour protection fitted in foreign ships, interrogation marks indicate that there is considerable doubt of the correctness of the figure given.

    (iii) Tables Nos. 5 and 8 give the approximate immunity zones of British and foreign ships where both side armour and deck armour will defeat the shell. The upper limit of the immunity zone is the lowest range at which the shell, due to its comparatively steep angle of descent, can attack and penetrate the vertical or side armour.

    The lower limit of the immunity zone is the maximum range at which the shell with its comparatively high remaining velocity can penetrate the vertical or side armour.

    (iv) Under certain conditions a range is reached below which a shell, due to its flat trajectory, cannot theoretically reach the magazines although it may penetrate the side armour. This range is termed the "Shut down" range. This "shut down" effect disregards the fact that a shell may be deflected downwards due to its striking some obstruction after passing through the side armour.

    (v) It must be emphasised that no real hard and fast line of demarcation can be drawn between what are immunity ranges and what are not. The theoretical angle of descent will obviously be compromised if the target is listed or rolling heavily. The inclination of the target to the line of fire will affect the range at which side armour can be penetrated. In addition, shell which theoretically should burst well inside a ship may be deflected or defeated by obstructions such as boats' davits, deck stiffeners, etc., which play no part in the theoretical armour protection.

    (vi) In Tables Nos. 6 and 8 giving probable immunity zones for foreign ships, those zones based on uncertain thickness of armour from Table No. 2, are indicated by an interrogation mark.

6

TABLE No. 1

ARMOUR
BRITISH FLEET

Class.
Vertical.
Horizontal.
Mag.
E.R.
B.R.
Mag.
E.R.
B.R.
King George V
15"
14"
14"
6"
5"
5"
Nelson
13"-14"
13"-14"
13"-14"
6¾"
4¼"
4¼"
Warspite
13"
13"
13"
4¼"
2¾"
2¾"
Barham
13"
13"
13"
4¼"
1"
1"
Malaya
13"
13"
13"
4¼"
2¾"
1"
Royal Sovereign
13"
13"
13"
2"
1"
1"
Royal Oak
13"
13"
13"
4"
2½"
1"
Renown
9"
9"
9"
4"
3"
2½"
Repulse
9"
9"
9"
4½"
3"
1"
Hood
12"
12"
12"
3"
2"
2"
Kent
4"
4½"
4½"
2½"
1 3/8"
1 3/8"
London
4"
1"
1"
2½"
1 3/8"
1 3/8"
York
4"
3"
3"
2½"
1½"
1½"
Exeter
5"
3"
3"
2½"
1½"
1½"
Leander
3½"
3"
3"
2"
1¼"
1¼"
Arethusa
3"
2¼"
2¼"
2"
1"
1"
Southampton
4½"
4½"
4½"
2½"
1¼"
1¼"
Belfast
4½"
4½"
4½"
3"
2"
2"
Fiji
3½"
3¼"
3¼"
2"
2"
2"
Dido
3"
3"
3"
2"
1"
1"

TABLE No. 2

ARMOUR
FOREIGN SHIPS

Class.
Vertical.
Horizontal.
Mag.
E.R.
B.R.
Mag.
E.R.
B.R.
French Fleet.            
    Lorraine
10¾"
10¾"
10¾"
1¾"
1¾"+1¾"
1¾"+1¾"
    Bretagne (2)
10¾"
10¾"
10¾"
1¾"
1¾"+1¾"
1¾"+1¾"
    Courbet (3)
10¾"
10¾"
10¾"
1¾"+1½"
1¾"+1½"
1¾"+1½"
    Dunkerque (2)
10.8"?
10.8"?
10.8"?
3"?
3"?
3"?
    Algerie
4.3"
4.3"
4.3"
3.1"
3.1"
3.1"
    Suffren (4)
?
2.4"?
2.4"?
¾"
¾"
¾"
    Duquesne (2)
¾"?
?
?
    La Galissionnaire (6)
4"
4"
4"
1½"
1½"
1½"
    Emil Bertin
?
?
?
2"?
?
?
    Jeanne D'Arc
3"?
?
?
    Duguay-Trouin (3)
¾"
½"
½"
    Com. Teste
2"
2"
2"
1½"
1½"
1½"
 
German Fleet.            
    Scharnhorst (2)
8"?12.6"
8"?12.6"
8"?12.6"
5.9"
5.9"
4"
?7.8"
?7.8"
?7.8"
     
    Deutschland
2 3/8"?
2 3/8"?
2 3/8"?
2 3/8"?
    Graf Spee (2)
4"
4"
4"
2¼"+4"?
2¼"?
2¼"?
    Blucher (3)
4"
4"
4"
3¼"
3¼"
3¼"
    Nurnberg
3"?
3"?
3"?
1"
1"
1"
    Leipzig
4"
4"
4"
1 3/8"
1 3/8"
1"
    Köln (3)
3"?
3"?
3"?
2"?
2"?
?
    Emden
4"
4"
3"
?
?
?

7

TABLE No. 2—continued

ARMOUR—continued
FOREIGN SHIPS
—continued

Class.
Vertical.
Horizontal.
Mag.
E.R.
B.R.
Mag.
E.R.
B.R.
Italian Fleet.            
    Littorio
?
?
?
?
?
?
    Duilio (2)
?
?
?
?
?
?
    Cavour (2)
9¾"
9¾"
9¾"
3"
?
?
    Zara (3)
6"
6"
6"
2¾"
2¾"
    Gorizia
8¼"
9 7/16"
9 7/16"
2½"
2½"
    Bolzano
2¾"?
2¾"?
2¾"?
2"
2"
2"
    Trento (2)
3"?
2¾"?
2¾"?
2"
2"
2"
    Abruzzi (2)
6"?
3"?
3"?
1½"?
1½"?
1½"?
    Montecuccoli (2)
1½"?
    D'Aosta (2)
4¾"?
4¾"?
4¾"?
    Diaz (2)
1¼"
1¼"
1¼"
1 5/8"
¾"
¾"
    Guissano (4)
1.6"?
1.6"?
1.6"?
1"
1"
1"
 
Japanese Fleet.            
    Nagato (2)
14"
14"
14"
7"
?
?
    Ise (2)
12"
12"
12"
4"?
2"
2"
    Fuso (2)
12"
12"
12"
4"?
2"
2"
    Kongo (3)
8"
8"
8"
3"?
(4"-5")?
3"
    Takao (4)
4"?
3"?
3"?
5"
    Nachi (4)
4"?
3"?
3"?
5"
3"
    Mogami (4)
2½"
2½"
2½"
2"
    Furutaka (2)
1"?
3"
3"
2"?
?
?
    Aoba (2)
1"?
3"
3"
2"?
?
?
 
Details of other Cruisers not known.
 
Spanish Fleet.            
    Canarias (1)
4"
1½"
1½"
2"
1¼"
1¼"
    Almirante Cervera (3)
2"?
3"?
3"?
1"
1½"
1½"
 
U.S.A. Fleet.            
    Colorado (3)
13½"
13½"
13½"
3½"+1½"?
3½"+1½"?
3½"+1½"?
    California (2)
13½"
13½"
13½"
3"?
3"?
3"?
    New Mexico (8)
13½"
13½"
13½"
5½"
5½"
5½"
    Arizona (2)
13½"
13½"
13½"
5"?
5"?
5"?
    Nevada (2)
13½"
13½"
13½"
5"
5"
5"
    Texas (2)
11"
11"
11"
5"?
2"
2"
    Arkansas
11"
11"
11"
2"?
2"?
2"?
    Quincey (2)
5"?
5"?
5"?
3"+2"?
?
?
    New Orleans
5"
5"
5"
3"?
3"?
3"?
    Portland (2)
4½"
4½"
4½"
?
2½"
2½"
    Augusta (6)
3"?
3"?
3"?
2"+1"?
?
?
    Pensacola (2)
2½"?
2½"?
2½"?
2"?
2"?
2"?
    Philadelphia (9)
4"
5"?
5"?
2"
3"?
3"?
    Omaha (10)
?
3"
3"
?
1½"
1½"

Notes

    (1) The number in brackets after the class name of ships indicates the number of ships in that class with approximately the same armour protection.
    (2) A question mark against a figure denotring thickness of armour indicates doubt of the correctness of the figure given.

8

TABLE No. 3

RANGE FOR PERFORATION OF DECK ARMOUR

Diameter and Weight of Shell
Thickness of Deck in inches.
1"
2"
3"
4"
5"
6"
7"
16"—2,375 lb.
14,500
19,500
23,500
27,500
30,500
33,500
16"—2,048 lb.
15,000
20,750
25,500
29,500
33,250
36,500
15"—1,938 lb.
14,250
19,500
24,000
27,500
31,000
34,000
15"—1,920 lb.
14,250
19,250
23,250
26,500
29,750
32,500
14"—1,590 lb.
15,000
20,500
25,000
29,000
32,250
35,500
14"—1,400 lb. (American H.V.)
18,500
24,000
28,500
32,500
36,000
13.6"—1,168 lb. (French)
15,000
22,500
27,500
32,000
35,500
12"—850 lb.
11,500
19,000
25,000
30,000
34,000
11"—661 lb. (German)
16,000
23,000
28,500
33,000
9.2"—380 lb. (Coast Defense)
12,000
21,500
8"—256 lb.
14,000
21,000
26,500
6.1"—124 lb. (French)
17,000
23,500
6"—112 lb.
14,500
22,000
6"—100 lb.
15,750
23,000
5.9"—103.6 lb. (German)
17,500
27,000
 
1"
1½"
2"
 
5.25"—80 lb.
16,000
20,000
4.7"—62 lb.
16,000
Note.—Blanks in bottom right-hand corner indicate that the shell even at extreme range cannot perforate the armour.

9

TABLE No. 4A

PERFORATION RANGE FOR THICKNESS OF VERTICAL ARMOUR IN INCHES

 
90° Inclination.
N.C.
C.
Gun.     Shell.
2½"
3"
4"
4½"
6"
8"
10"
12"
14"
16"
16"        2,375 lb.
28,000
22,250
18,000
16"        2,048 "
26,000
20,500
16,000
12,000
15"        1,938 "
26,000
19,500
15,000
11,000
15"        1,920 "
20,000
16,000
12,000
9,000
14"        1,590 "
25,000
19,500
14,500
14"         U.S.A. ( H.V.)
22,000
17,250
13,500
13.6"      French
21,000
17,500
14,000
12"         850 lb.
15,000
11,500
8,500
11"        German
26,500
20,000
16,000
13,000
9.2"       Coast Defense
21,000
16,000
11,000
8"          256 lb.
28,000
21,000
17,000
13,000
9,000
6.1"       French
21,500
18,500
13,500
10,000*
6"          112 lb.
18,000
14,500
10,500
7,000*
5.9"       German
20,000
17,000
13,500
9,000*
5.25"     80 lb.
13,000
11,250
8,000*
4.7"        62 "
11,500
9,500
7,000*
4.7"        50"
6,500
5,250
4.5"        55"
11,500
8,500

* Although perforation is to be expected at these ranges, correct detonation is improbable and only minor damage will result. Blank spaces in the top left-hand corner of each table indicate that the shell will defeat the armour even at its maximum range. Blank spaces at the bottom right-hand side of the tables indicate that the shell can never perforate the armour.

10

TABLE No. 4B

PERFORATION RANGE FOR THICKNESS OF VERTICAL ARMOUR IN INCHES—continued

 
90° Inclination.
N.C.
C.
Gun.     Shell.
2½"
3"
4"
4½"
6"
8"
10"
12"
14"
16"
16"        2,375 lb.
29,000
23,000
18,000
13,500
16"        2,048 "
21,500
16,500
12,000
8,000
15"        1,938 "
21,000
15,000
11,000
15"        1,920 "
16,500
12,500
9,000
14"        1,590 "
20,000
15,500
10,500
14"         U.S.A. ( H.V.)
18,500
14,000
10,000
13.6"      French
18,000
14,500
11,500
12"         850 lb.
13,000
9,000
6,000
11"        German
23,000
18,000
14,000
10,500
9.2"       Coast Defense
18,000
13,500
9,000
8"          256 lb.
24,500
18,000
15,000
11,000
7,000
6.1"       French
18,500
16,000
11,500
6"          112 lb.
16,000
12,500
9,000
5,500*
5.9"       German
17,000
15,000
12,000
5.25"     80 lb.
12,000
9,500
6,500*
4.7"        62 "
10,000
8,000
4.7"        50"
5,500
4,500
4.5"        55"
9,500
7,000

* Although perforation is to be expected at these ranges, correct detonation is improbable and only minor damage will result. Blank spaces in the top left-hand corner of each table indicate that the shell will defeat the armour even at its maximum range. Blank spaces at the bottom right-hand side of the tables indicate that the shell can never perforate the armour.

11

TABLE No. 5

BRITISH CAPITAL SHIPS—APPROXIMATE IMMUNITY RANGES TO CHANCE VITAL HITS IN MAGAZINES AND SPEED HITS IN MACHINERY SPACES FROM FOREIGN CAPITAL SHIPS' GUNFIRE

90° Inclination

1
2
3
4
5
6
7
Britsh, under fire from
16"
(Japan, U.S.A.)
15"
(Germany, Italy, France)

14" Medium Velocity
(Japan, U.S.A.)

14" High Velocity
(U.S.A.)
12.6"
(Italy)
11"
(Germany)
Class.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
King George V (5)
14-33
16-30
13-31
15-27
0-32
14-29
0-36
14-32
Immune
0-34
Immune
Immune
Nelson (2)
16-35
16-26
15-33
15-25
15-35
15-27
14-up
14-29
Immune
0-31
Immune
0-33
Royal Sovereign (4)
0
0
0
0
0
0
15-18
0
0-19
0-11
0-23
0-16
Royal Oak (1)
18-25
0
17-24
0
17-25
0
15-28
0
0-30
0-11
0-33
0-16
Warspite (3)
18-26
18-19
17-25
17-18
17-26
17-19
15-29
15-22
0-31
0-24
0-33
0-27
Barham (1)
18-26
0
17-25
0
17-26
0
15-29
0
0-31
0-12
0-33
0-16
Malaya (1)
18-26
0
17-25
0
17-26
0
15-29
0
0-31
0-12
0-33
0-16
Hood (1)
0
0
0
0
19-20
0
17-24
17-18
9-25
9-19
13-28
13-23
Renown (1)
0
0
0
0
0
0
0
0
13-30
13-22
18-33
18-25
Repulse (1)
0
0
0
0
0
0
0
0
13-32
0
18-up
0

Notes

      (1) Figures are given in thousands of yards.
      (2) The "shut down"* range for all ships is of the order of 12,000 yards at 90° inclination, and decreases as the inclination narrows.
      (3) The perforation range for vertical armour decreases as the inclination narrows, thereby giving a broadening of the immunity zones.

*See Introduction, para. (iv)

12

TABLE No. 6

FOREIGN CAPITAL SHIPS—APPROXIMATE IMMUNITY RANGES TO CHANCE VITAL HITS IN MAGAZINES AND SPEED HITS IN MACHINERY SPACES FROM BRITISH CAPITAL SHIPS' GUNFIRE

90° Inclination

1
2
3
4
5
Country and Class.
16"
(Nelson's).
Old—15"
(All 15" ships except those in column 4)

New—15"
(Warspite, Queen Elizabeth, Valiant, Renown).

14"
(King George V's).
 
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
France.                
    Richelieu (2)
    Bretagne (2)
None
None
None
18-19
None
None
None
None
    Lorraine (1)
None
None
None
None
None
None
None
None
    Courbet (2)
None
None
18-19
18-19
None
None
None
None
    Dunkerque (2)
None
None
18-19
18-19
None
None
None
None
                 
Germany.                
    Tirpitz (2)
    Scharnhorst (2)
19-33
19-25
15-30
15-23
18-31
18-24
18-32
18-25
    Deutschland (2)
    Graf Spee (1)
}
None
None
None
None
None
None
None
None
                 
Italy.                
    Littoria (2)
?
?
?
?
?
?
?
?
    Duilio (2)
?
?
?
?
?
?
?
?
    Cavour (2)
26-?
26-?
20-?
20-?
26-?
26-?
24-?
24-?
                 
Japan.                
    Nagato (2)
16-36
16-?
12-32
12-?
15-34
15-?
14-35
14-?
    Ise, Fuso (4)
20-25
None
16-23
None
19-25
None
19-25
None
    Kongo (3)
None
None
None
None
None
None
None
None
                 
U.S.A.                
    Colorado (3)
17-25
17-25
13-23
13-23
16-24
16-24
16-25
16-25
    Tennessee (2)
17-21
17-21
13-19
13-19
16-19
16-19
16-20
16-20
    New Mexico } (7)
17-29
17-29
13-26
13-26
16-27
16-27
16-29
16-29
    Pennsylvania
    Nevada
    Texas (2)
None
None
None
None
None
None
None
None

Notes

      (1) Figures are given in thousands of yards.
      (2) Numbers in brackets after the class name of ships indicates number of ships in that class .
      (3) Interrogation marks indicate doubt or lack of knowledge of armour thickness upon which immunity ranges are based
      (4) The "perforation" range for vertical armour decreases as the inclination narrows, thereby giving a broadening of the immunity zones.

13

TABLE No. 7

BRITISH CRUISERS—APPROXIMATE IMMUNITY RANGES TO CHANCE VITAL HITS IN MAGAZINES AND SPEED HITS IN MACHINERY SPACES FROM VARIOUS CALIBRES OF GUNS

90° Inclination

Britsh, under fire from
8"
6.1"
(French)

6"
(112 lb. Proj.).

5.9"
(German).
5.25"
(80 lb. Proj.).
4.7"
(62 lb. Proj.).
Class.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
Kent
21-23.5
17-18
Above 13.5
10-20
Above 10.5
7-18
Above 13.5
9-22
Above 8
Below 20
Above 11.5
Immune
London
21-23.5
None
Above 13.5
None
Above 10.5
None
Above 13.5
None
Above 8
None
Above 11.5
None
York
21-23.5
None
Above 13.5
18.5-20
Above 10.5
14.5-18
Above 13.5
17-22
Above 8
11.25-20
Above 11.5
Above 9.5
Exeter
16-23.5
None
Immune
18.5-20
Immune
14.5-18
Immune
17-22
Immune
11.25-20
Immune
Above 9.5
Leander
None
None
16-23.5
None
12.5-22
None
15-27
17-20
Above 10
11.25-16
Above 8.5
9.5-16
Arethusa
None
None
18.5-23.5
None
14.5-22
None
17-27
None
Above 11.25
15-16
Above 9.5
13-16
Southampton
17-24
None
Above 10
10-17
7-22
7-16
Above 9
9-20
Immune
Below 16
Immune
Below 16
Belfast
17-26.5
17-21
Above 10
10-23.5
Above 7
7-22
Above 9
9-27
Immune
Immune
Immune
Immune
Fiji
None
None
16-23.5
17.5-23.5
12.5-22
13.5-14.5
15-27
16-27
Above 15
Above 10.5
Above 8.5
Above 9
Dido
None
None
18.5-23.5
None
14.5-22
None
17-27
None
Above 11.25
11.25-16
Above 9.5
9.5-16

Notes

      (1) Figures are given in thousands of yards.
      (2) The "shut down"* range for all ships is of the order of 12,000 yards at 90° inclination, and decreases as the inclination narrows.
      (3) The perforation range for vertical armour decreases as the inclination narrows, thereby giving a broadening of the immunity zones.

*See Introduction, para. (iv)

14

TABLE No. 8

FOREIGN CRUISERS—APPROXIMATE IMMUNITY RANGES TO CHANCE VITAL HITS IN MAGAZINES AND SPEED HITS IN MACHINERY SPACES FROM VARIOUS CALIBRES OF GUNS

90° Inclination

Country and Class.
8"
6"
(112 lb. Proj.)

5.25"

4.7"
(62 lb. Proj.).
 
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
C.V.H.
Speed.
France.                
    De Grasse (3)
?
?
?
?
?
?
?
?
    Algerie (1)
21-26.5
21-26.5
Above 10.5
Above 10.5
Above 8
Above 8
Above 7
Above 7
    Suffren (4)
?
None
?
18-?
?
13-?
?
11.5-?
    Duquesne (2)
None
None
None
None
None
None
None
None
    La Galissionaire (6)
None
None
10.5-18
10.5-18
8-20
8-20
Above 7
Above 7
    Emile Bertin (1)
?
?
?
?
?
?
?
?
    Jeanne D'Arc (1)
None
None
None
None
None
None
None
None
    Duguay-Trouin (3)
None
None
None
None
None
None
None
None
    Com. Test (1)
None
None
None
None
15-20
15-20
Above 12
Above 12
                 
Germany.                
    Nurnberg (1)
None ?
None ?
None ?
None ?
11.25-16?
11.25-16?
9.5-16?
9.5-16?
    Leipzig (1)
None ?
None ?
10.5-20
10.5-14.5
8-20?
8-16?
Above 7?
7-16?
    Koln (3)
None ?
None ?
14.5-22?
14.5-22?
Above 11.25?
11.25-?
Above 9.5?
9.5-?
    Emden (1)
Above 21 ?
Above 28?
Above 10.5?
Above 14.5?
Above 8?
Above 11.25?
Above 7?
Above 9.5?
    Blucher (3)
?
?
?
?
?
?
?
?
                 
Italy.                
    Zara (3)
13-25
?
Above 7
?
Immune
?
Immune
?
    Gorizia (1)
9-24
?
Immune
?
Immune
?
Immune
?
    Bolzano (1)
20-21?
20-21?
16-22?
16-22?
Above 12?
Above 12?
Above 10.5?
Above 10.5?
    Trento (2)
18.5-21?
20-21?
14.5-22?
16-22?
Above 11.25?
Above 12?
Above 9.5?
Above 10.5?
    Abruzzi (2)
13-17.5 ?
None ?
Below 18?
14.5-18 ?
Below 20
11.25-20 ?
Immune?
Above 9.5?
    Montecuccoli (2)
None ?
None ?
None ?
None ?
None ?
None ?
None ?
None ?
    D'Aosta (2)
?
?
?
?
?
?
?
?
    Diaz (2)
None
None
None
None
?
?
?
?
    Guissano (4)
None
None
None
None
?
?
?
?

15

Japan.                
    Takao (4)
Above 21?
None?
Above 10.5?
None?
Above 8?
None?
Above 7?
None?
    Nachi (4)
Above 21?
None?
Above 10.5?
None?
Above 8?
None?
Above 7?
None?
    Furutaka (2)
None?
28-?
None
14.5-?
None?
11.25-?
None?
9.5-?
    Aoba (2)
None?
28-?
None
14.5-?
None?
11.25-?
None?
9.5-?
    Mogami (4)
None
None
18-22
None
Above 13
None
Above 11.5
None
    Tone (2)
?
?
?
?
?
?
?
?
    Natori (6)
None
None
18-?
18-?
13-?
13-?
11.5-?
11.5-?
                 
Spain.                
    Canarias (1)
None
None
10.5-22
None
Above 8
None
Above 7
None
    Alm. Cervera (3)
None?
None?
None?
14.5-18
12-16?
11.25-20?
10-16?
Above 9.5?
                 
U.S.A.                
    Wichita (1)
?
?
?
?
?
?
?
?
    Savannah (7)
?
?
?
?
?
?
?
?
    Quincey (7)
?
?
?
?
?
?
?
?
    New Orleans (5)
Below 26.5?
Below 26.5?
Immune?
Immune?
Immune?
Immune?
Immune?
Immune?
    Portland (2)
?
Below 24?
?
Immune?
?
Immune?
?
Immune?
    Augusta (6)
None
None
14.5-22?
None
Above 11.25
15-20
Above 9.5
Above 13
    Pensacola (2)
None?
None?
18-22?
18-22?
Above 13?
Above 13?
Above 11.5?
Above 11.5?
    Philadelphia (9)
None
16-26.5?
10.5-22
Immune?
Above 8?
Immune?
Above 7?
Immune?
    Omaha (10)
?
None
?
14.5-18
?
11.25-20?
?
Above 9.5

Notes

      (1) Figures are given in thousands of yards.
      (2) Numbers in brackets after the class name of ships indicates number of ships in that class .
      (3) Interrogation marks indicate doubt or lack of knowledge of armour thickness upon which immunity ranges are based
      (4) The "perforation" range for vertical armour decreases as the inclination narrows, thereby giving a broadening of the immunity zones.

END OF TRANSCRIPTION