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Steel Armor Plate Rating

This program calculates a simple estimation of the effectivenes a steel armor plate, by taking as parameters the thickness of the plate, its slope (if any) and an estimation of the average quality of the material, which is its ability to whitstand impacts from artillery shells of calibers up to 203 millimeters. The slope or angle is 0 for vertical or horizontal surfaces, a negative number if the inclination is outwards (like \) and a positive number if it is otherwise. The program is complete with a list of many homogeneous and face-hardened steel types, used in the past to build the armor schemes of warships, and their average quality values in comparison with the American B-class homogeneous armor of the World War Two era.

Below there is a list showing the values for many historical capital ships, including two ironclads. The higher the number, the higher the rating of the protection scheme on the corresponding ship. Ironclads and the first pre-dreadnought battleships were built with the thickest armor belts ever seen, and because of this they get relatively high ratings on the list. Ended the age of ironclads, capital ships reduced the thickness of their armor to achieve higher speeds. Despite the progress on metallurgy, the newer battleships had comparatively weaker armor schemes, but they compensated this with increased speed and above all a striking firepower.

PHP application by Sakhalia Net Project

Thickness (millimeters):
Angle (degrees - 45 maximum):
Steel Quality:




Battleship Yamato (1940)
Overall: 431.7
Main belt: 73
Main/armored deck: 41.7
Barbettes: 78.9
Main turrets face: 154.2
Conning tower: 83.9
Battleship Iowa (1942)
Overall: 380.4
Main belt: 72.8
Main/armored deck: 30.1
Barbettes: 73.2
Main turrets face: 115.5
Conning tower: 88.8
Battleship Richelieu (1939)
Overall: 343.3
Main belt: 67.8
Main/armored deck: 27.2
Barbettes: 81
Main turrets face: 99.3
Conning tower: 68
Battleship Nelson (1925)
Overall: 306.3
Main belt: 67.4
Main/armored deck: 27
Barbettes: 68.6
Main turrets face: 82.1
Conning tower: 61.2
Battleship Vittorio Veneto (1937)
Overall: 292.5
Main belt: 69.9
Main/armored deck: 30
Barbettes: 68.6
Main turrets face: 73
Conning tower: 51
Battleship Bismarck (1939)
Overall: 282.9
Main belt: 62.4
Main/armored deck: 24
Barbettes: 53.8
Main turrets face: 73.6
Conning tower: 69.1
Battleship Bayern (1915)
Overall: 276.2
Main belt: 58
Main/armored deck: 12
Barbettes: 58
Main turrets face: 82
Conning tower: 66.2
Battleship Dunkerque (1935)
Overall: 274.5
Main belt: 51.8
Main/armored deck: 23.5
Barbettes: 69
Main turrets face: 76.2
Conning tower: 54
Battlecruiser Scharnhorst (1936)
Overall: 271.5
Main belt: 67.9
Main/armored deck: 10
Barbettes: 52.8
Main turrets face: 73.6
Conning tower: 67.2
Battleship Mutsu (1920)
Overall: 247.5
Main belt: 51.9
Main/armored deck: 11.1
Barbettes: 51.9
Main turrets face: 69.9
Conning tower: 62.7
Ironclad Caio Duilio (1876)
Overall: 238.5
Main belt: 77
Main/armored deck: 9.1
Barbettes: 63
Main turrets face: 40.4
Conning tower: 49
Battleship New York (1912)
Overall: 235
Main belt: 53.7
Main/armored deck: 12.2
Barbettes: 50.5
Main turrets face: 68.1
Conning tower: 50.5
Battleship King George V (1939)
Overall: 233.9
Main belt: 69.7
Main/armored deck: 25.2
Barbettes: 56.6
Main turrets face: 61.2
Conning tower: 21.2
Ironclad Andrea Doria (1885)
Overall: 232
Main belt: 67.5
Main/armored deck: 10.6
Barbettes: 54
Main turrets face: 62.4
Conning tower: 37.5
Battleship Viribus Unitis (1912)
Overall: 223.1
Main belt: 53
Main/armored deck: 7.7
Barbettes: 53
Main turrets face: 56.4
Conning tower: 53
Battlecruiser Hood (1918)
Overall: 221.6
Main belt: 53
Main/armored deck: 9.7
Barbettes: 36.7
Main turrets face: 74.8
Conning tower: 47.4
Battleship King Edward VII (1903)
Overall: 214.8
Main belt: 37.9
Main/armored deck: 10.1
Barbettes: 58
Main turrets face: 58.3
Conning tower: 50.5
Battleship Queen Elizabeth (1913)
Overall: 202
Main belt: 56.1
Main/armored deck: 8.5
Barbettes: 30.3
Main turrets face: 59.7
Conning tower: 47.4
Battlecruiser Derfflinger (1913)
Overall: 199.1
Main belt: 49.9
Main/armored deck: 8.8
Barbettes: 43.1
Main turrets face: 47.6
Conning tower: 49.7
Battleship Charles Martel (1893)
Overall: 196.1
Main belt: 69.9
Main/armored deck: 10.6
Barbettes: 22.8
Main turrets face: 57.8
Conning tower: 35
Battleship Dreadnought (1906)
Overall: 189.9
Main belt: 46.2
Main/armored deck: 7.7
Barbettes: 31.5
Main turrets face: 58.3
Conning tower: 46.2
Battleship Mississippi (1905)
Overall: 188.4
Main belt: 37.9
Main/armored deck: 12.2
Barbettes: 42.1
Main turrets face: 58.3
Conning tower: 37.9
Battleship Kaiser Barbarossa (1900)
Overall: 187.2
Main belt: 50.5
Main/armored deck: 10.4
Barbettes: 42.1
Main turrets face: 42.1
Conning tower: 42.1
Battleship Knyaz Suvorov (1902)
Overall: 157.5
Main belt: 33.6
Main/armored deck: 6.1
Barbettes: 42.1
Main turrets face: 42.1
Conning tower: 33.6
Pocket battleship Admiral Graf Spee (1934)
Overall: 101.5
Main belt: 16.4
Main/armored deck: 9
Barbettes: 20
Main turrets face: 26.1
Conning tower: 30