Cement armour. How to rate it?

[Dili]

I have an Italian armed pontoon with 2.9m of Concrete in belt. What would be the comparative Steel armor value?

[el cid again]

ORIGINAL: Dili

I have an Italian armed pontoon with 2.9m of Concrete in belt. What would be the comparative Steel armor value?

29 mm?? It isn't exactly armor in the usual sense. There is more than the problem of "what happens when the shell hits?" There is "what happens when the next shell hits?" in a greater sense than with other types of armor.

[Mike Scholl]

ORIGINAL: Dili

I have an Italian armed pontoon with 2.9m of Concrete in belt. What would be the comparative Steel armor value?

Is is listed as "feroconcrete" or "reinforced concrete"? This stands up well to shellfire (not as well as armor plate, but being cheaper it can be made thicker).

[Dili]

El cid: 2900mm not 29mm
 
Mike Scholl :

The hull was a rectangle with a high prominent crown down the centerline. Surrounding all four sides, since the bow was 27m in width and matched the 27m width of the stern, was concrete cofferdam 2.9m in width, which provided armor. A ship armored with a ten-foot belt of concrete certainly has to be considered odd.

 
Source: http://steelnavy.com/RMFaaDiBruno.htm

[el cid again]

I was answering the question.

During military police training, we get to study what happens when you shoot at things. Also, sometimes, to actually shoot at things. Things people think protect them include cars - nominally made of steel (but not much anymore) - and brick, block and concrete walls. None of them are reliable protection from high powered rifle fire - never mind major shell fire. Even some pistol rounds are able to penetrate. The only good news is that the flight path of the bullet is ALWAYS changed - period - no exceptions.

I don't know what the proper ratio should be? A reasonable guess would be "divide by 10" or 290 mm. But given what I have seen - on film of tests and actually testing - I think it is worse than that. I would rather be prone than exposed defended by "concrete armor."