Fred T Jane's Naval Artillery Equivalence Table

This data was originally published in All The World's Fighting Ships (1898).

Gun Classification Muzzle Energy
(in foot tons)
Britain
Armstrong, Whitworth, Woolwich
France
Canet, Schneider
Germany
Krupp
Russia
Obutchoff
Spain
Hontario, Ordoņez
U.S.A.
A circa > 20,000 17", 16.25", 13.5", 12" (wire), 11" (Elswick 42 cal.)
(= 43.2cm, 41.4cm, 34.3cm, 30,5cm, 28cm)
37cm, 34cm, 30cm, 27cm
(= 14.5", 13.4", 11.8", 10.6")
35.5cm, 28cm (40 cal.)
(= 14", 11")
30.48cm
(= 12")
32cm, 28cm
(= 12.6", 11")
13", 12"
(33cm, 30.48cm)
B 20,000 to 14,000 12", 10", 9.2" (wire), 12.5"
(= 30.5cm, 25.4cm, 23.4cm, 32cm)
42cm, 24cm (40 cal. - 1893)
(= 16.5", 9.4")
28cm (35 cal.), 24cm (50, 45, & 40 cal. - 1896)
(= 11" (short), 9.4" (long & medium)
30.48cm (30 cal.), 20.32cm (35 cal.)
(= 12", 8")
- 10" (35 cal.)
(= 25.4cm)
C 14,000 to 6,000 9.2", 8" (15 tons), 8" (14 tons), 12" (old), 11" (old)
(= 23.4cm, 20.3cm, 20.3cm, 30.5cm (old), 28cm (old)
27cm (1884), 24cm (30 cal. - 1884), 19.4cm, 19cm (45 cal. - 1887)
(= 10.6", 9.4", 7.6", 7.5")
26cm, 24cm, 21cm (35 cal.)
(= 10.2", 9.4", 8.3")
30.48cm (old), 28cm, 22.86cm (35 cal.)
(= 12" (old), 11", 9")
24cm, 20cm
(= 9.4", 7.9")
10" (30 cal.)
(= 25.4cm)
D 6,000 to 2,000 8" (14 tons) (old), 6", 10" (old), 9" (old)
(= 20cm (old), 15.2cm, 25.4cm (old), 22.8cm (old))
16cm, 15cm, 14cm (28 cal.), 12cm (80 & 60 cal.)
(= 6.3", 5.5", 4.7")
24cm (old), 21cm (old), 17cm, 15cm (27 cal.)
(= 9.4" (old), 8.3" (old), 6.7", 6")
22.86cm (old), 15.24cm (33 cal.), 20.32cm
(= 9" (old), 6", 8")
18cm, 16cm (35 cal.), 14cm
(= 7", 6.3", 5.5")
6"
(= 15cm)
E 2,000 to 800 4.7", 4", 5", 7" (old)
(= 12cm, 10cm, 12.5cm, 17.8cm (old)
14cm, 12cm, 10cm, 9cm
(= 5.5", 4.7", 3.93", 3.54")
15cm (19 cal.), 12.5cm, 10.5cm, 12cm, 8.7cm (50 cal.)
(= 6", 4.8", 4", 4.7", 3.4")
20.32cm (old), 15.24cm (old), 15.32cm (old)
(= 8" (old), 6" (old), 6.1" (old))
16cm (25 cal.) (old), 12cm
(= 6.3" (old), 4.7")
5", 4"
(12.5cm, 10cm)
Z 800 to 500 4", 3" (12 pdr.)
(= 10cm, 7.6cm)
9cm, 7.5cm, 6.5cm (80 cal.)
(= 2.9", 2.5")
8.7cm (40 cal.), 8.4cm, 8cm, 7.5cm
(= 3.4", 3.3", 3", 2.9")
10.6cm
(= 4")
- Old smooth bore guns

The armour fitted to ships was similarly classified by letters, with each lower case letter corresponding approximately to the thickness of armour that the gun with the same upper case letter was expected to penetrate at close range in actual combat.

Armour Classification Harvey Nickel Steel Armour Harvey Steel Armour Compound Armour Iron Armour
a = 8" = 9" = 11" = 17"
b = a little inferior to the above = 14" (approximately)
c = 5" = 6" = 9" = 12"
d - = 4" = 6" = 8"
e = thin armour

Key

cal. = Calibre
pdr. = pounder
ton = 20 cwt. or 2240 lbs.
wire = Wire wound barrel

This data was originally published in All The World's Fighting Ships (1898).

Š Robert George Cordery (2005)