War on the Sea – Shell Penetration


Shell Penetration

Armor is used to protect vital systems from hits.


It is represented as the thickness of armor plating in a specific region of a ship (in inches or millimeters). There are other factors such as the materials used, quality of armor as well as slope. Armor at a sloped angle deflects incoming shells better, making it much more effective without having to actually thicken it.


The hull of a ship has two armor values: belt (vertical) and deck (horizontal) which represent the protection against a hit to the side or a hit from above.


Regions of the superstucture and gun turrets of a ship have a single armor value.


Shell Hits

The following factors determine whether a shell will penetrate armor:


Caliber – Larger shells can punch through thicker armor.


Muzzle Velocity – Higher velocity shells possess more energy to penetrate armor.


AP Shell – Armor-piercing shells have a smaller explosive warhead, but penetrate armor about 5x better than a HE shell of similar caliber.


Striking Angle – Shell strikes at shallow angles may simply bounce away (ricochet).


Short Range – shell has a higher velocity with shallow trajectory. It can punch through belt armor but ricochet off of deck armor.


Long Range – shell arcs downward with steep trajectory. It can ricochet off belt armor but penetrate deck armor (called plunging fire).



When an AP shell strikes armor the following may occur:


– Shell caliber is greater than 14x the thickness of armor struck, it automatically penetrates and explodes doing full damage.


– Shell strikes, penetrates the armor, and explodes doing full damage.


– Shell strikes at a shallow angle and is deflected (ricochet) doing 20% damage.


– Shell fails to penetrate armor and explodes externally, causing only 20% damage.


High explosive (HE) shells do an additional 25% damage.


HE shells can still penetrate armor but are as only as effective as an AP shell about 1/5th of their caliber.


Any hit to an unarmored part of a ship (or if shell caliber is greater than 14x armor thickness struck), will automatically penetrate and explode doing full damage.


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