Major historical naval armor penetration formulae

(Окун Натан. Основные исторические формулы бронепробития, используемые в военно-морском флоте).Scientific articles in pdf – format, – 7 p.The following formulae give the thickness "T" of iron or steel armor penetrated with increasing striking velocity "V" at a given impact angle ("obliquity") "Ob" by naval gun projectiles of various diameters "D" and weights "W" in use at the time. The definition of "penetration" varies and usually is either the "Nose Through" or "Through Crack" Ballistic Limit (later called in the U.S. the "Army" Ballistic Limit) or the "Base Through" or "Complete Penetration" or "Perforation" Ballistic Limit (later U.S. terminology was "Navy" Ballistic Limit), though other definitions have been used less often. This is not always clear cut, since, for example, a shattered projectile in many pieces may pass through the plate, but exactly how many pieces will constitute a penetration by these definitions?Contents:
Introduction.
Wrought iron armor.
Face-hardened armor.
"Universal" formulae.