478 
THE DEVELOPMENT ' OE ^ ARMOUR. 
Fig . 11, 
was 3 m (9 ft. 10-1 in. by l-9 ra (6 ft. 2'8 in.) by)300 (11-81 in.) and 
weighed 18 - 27 tons. The following table shows the attack on it. 
Krupp 
11-81 in 
plate, 1896 
No. of round. 
Calibre in 
Projectile, 
weight. 
Striking 
velocity. 
Calculated perforation 
of iron. 
c.m. 
inches. 
lbs. 
f.s. 
inches. 
1 
r7i6-i 
1753 
21-5 
2 
V30-5 
12-01 
\ 715-4 
1889 
23-9 
3 
) 
C712-7 
1993 
25-9 
All the projectiles were broken up without effecting perforation (see 
Figs. 11 and 12) and there were no serious cracks. Found No. 3 was a 
tremendous test both as to perforation and shock. The figure of merit 
or relation of actual plate to theoretical perforation of iron is 2’19. The 
striking energy is 19,630 foot tons or 1,479 foot tons per ton of plate. 
The plate entirely defeated the attack and exhibited an extraordinary 
combination of hardness and toughness. The projectile was very large 
in comparison to the area of the plate, forming a wedge of a diameter 
nearly one-sixth the width of the plate. The plate is a champion one, 
selected by the makers and not bent to form; but allowing for this, 
the result was a remarkable success for a thick plate and up to the 
present moment has been hardly ever equalled and never beaten. In 
fact the only plate comparing well with it is the Vickers 12-in., tested 
in 1897 (to be given hereafter) made by the same process. 
