--------------+-------------+----------------+------------- Calibre of | Weight of | Thickness of | Velocity for shot | shot | plate | penetration --------------+-------------+----------------+------------- 4-inch | 33[3] | { 4-inch | 1,930 | | { 5-inch | 2,295 | | | 4.7-inch | 45[3] | 5-inch | 2,220 | | | 5-inch | 58 | { 5-inch | 2,005 | | { 6-inch | 2,320 | | | 6-inch | 106 | { 6-inch | 1,950 | | { 8-inch | 2,450 | | | 8-inch | 316 | { 8-inch | 1,760 | | { 10-inch | 2,100 | | | 10-inch | 604 | { 10-inch | 1,745 | | { 12-inch | 2,020 | | | 12-inch | 1,046 | 12-inch | 1,730 --------------+-------------+----------------+------------- [3] Weight uncapped. For intermediate thickness the velocity shall be determined by interpolation. (b) Armor-piercing shell. Two capped shell, sandloaded to standard weight, shall be fired against a hard-faced Harveyized armor plate secure to a timber backing in a manner satisfactory to the Chief of Ordnance, of 3-inches thickness for 5-inch and 6-inch shell, 4-inches for 8-inch shell, 5-inches for 10-inch shell, and 6-inches for 12-inch shell, with a velocity[4] of about 1,420 f.s. for the 5-inch shell, 1,220 f.s. for the 6-inch shell and 920 f.s. for the 8-inch, 10-inch and 12-inch shell at impact, with the requirement that the shell shall go through the plate unbroken, and then be in a condition for effective bursting. [4] The weight of powder charge to give the prescribed velocity will be determined shortly before the test, cast iron projectiles of proper weight being fired for the purpose; this weight of charge will be taken as giving the prescribed velocity to the projectiles undergoing test. * * * * * (c) 12-inch deck piercing shell. Two shell, sandfilled to standard weight, will be fired with a striking velocity sufficient to pass completely through a 4-1/2-inch nickel-steel protective-deck plate inclined so as to give an angle of impact of 60 degrees, and to be supported by a suitable backing of wood; or both shell shall be subjected to such alternate ballistic test as the Department may judge to be an equivalent to the above in its effect upon the projectile. * * * * *