Armor penetration values for guns

[st9635]

Hi ...

When you look at the armor penetration values for the guns in the game, what type of armor is it based on?  Is it iron, compound, Harvey, Krupp xx armor (regardless of year)?  I'd think that the penetration values would be different based on the armor it's shooting at.

[GUTB]

I believe the armor values you see in the menus is some standardized minimum strength steel. The figure you see in the armor thickness settings is the same but normalized via weight and cost. Eg, 10" is 10" regardless of what kind of armor type , the difference is how much each unit costs and weighs. I believe this is why the in-game tooltip shows extremely high armor values sometimes, it's representing higher quality armor via thickness of minimum quality armor to provide an indication of relative strength vs the armor piercing value.

[Hangar18]

I believe iron.

[st9635]

I've done some testing and i think the gun's penetration values is based off iron armor but i get conflicting information from testing. 

The test setup was as follows (This took a while because the computer kept creating enemy designs w/torpedoes or ships with smaller caliber main guns .)   

---Range between ships under 1000 meters.  Only the enemy fires. 

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Krupp IV plate at 10.5 inches thickness vs 12 inch main guns with penetration of 19.3 inches (of iron plate?)  @ 1000 meters

1940 battleship:  10.5 in krupp iv armor for all areas vs. 1890 battleship with 12 inch main guns . 

The enemy 12 inch guns didn't penetrate on any shots at any range down to 100 meters (0.1 from the game hud). 

I think this is correct since the game says that krupp iv is 2x stronger than iron so 10.5 inch krupp iv plate = 21 inch iron plate

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Wrought Iron plate at 21.5 inches vs 12 inch main guns with penetration of 19.3 inches (of iron plate?)  @ 1000 meters

Next i tried a 1898 battleship w/ 21.5 inch iron belt, extended belt, conning tower and 10 inch deck, 1.5 DE and turrets against a similar 1890 battleship with 12 inch main guns. 

The enemy 12 inch main guns penetrated the 21.5 in belt armor and extended belt armor from 1000 meters down to 100 meters.  Even the 5 in guns penetrated the belt armor at less than 1000 meters?  The 3 in guns penetrated the 10 inch deck armor.  This doesn't seem right. 

This design should defeat the 12 inch guns (actually, it should defeat all the guns) since 21.5 iron armor plate is greater than 19.3 penetration .   But...why is this result different.  Maybe a bug?