Shock factor is a commonly used figure of merit for estimating the amount of shock experienced by a naval target from an underwater explosion as a function of explosive charge weight, slant range, and depression angle (between vessel and charge).
The numeric result from computing the shock factor has no physical meaning, but it does provide a value that can be used to estimate the effect of an underwater blast on a vessel.
Table 1 describes the effect of an explosion on a vessel for a range of shock factors.
Many of the internal mechanical systems (e.g. engine coupling to prop) require precise alignment in order to operate.
These cycles can introduce violent vibrations into a hull, generating structural damage, even to the point of breaking the ship's keel.