Armor Against Missiles

There are a few naval topics that just seem to trigger controversy and argument (like battleships) and armor, for unfathomable reasons, is one of them.  Armor would seem to be something that no one could possibly object to.  At its very worst, it mitigates damage and improves survivability and yet some people seem to want to argue against it.
 
One of the reasons for the reaction to armor is that many/most people have a couple of misconceptions which cloud their thinking.  Let’s examine those misconceptions and dispense with them.
 
 
Purpose – So many people seem to think that if armor can’t provide absolute and total invulnerability to every weapon past, present, and future that the armor has no value.  This is, of course, utter nonsense.  Armor does provide immunity to the types of weapons it’s designed to and it provides mitigation to the rest which improves survivability.  This was thoroughly covered in the post, “Armor for Dummies”, so I won’t belabor it further, here.
 
Note that no one has ever claimed that armor can provide total immunity against every threat ever conceived.  Thus, there is nothing to argue on this point and yet so many people illogically attempt to just that.
 
System vs Single Plate – So many people seem to think that armor is a single plate of steel welded onto the side of a ship.  While that has been done in the past, that is not what the majority of WWII armor schemes did.  Note the use of the word, ‘scheme’.  This means that armor was not (is not) a single plate of steel but is, instead, a system of various components acting in a layered effect to achieve mitigation of a weapon’s impact.  As an example, torpedo armor was not a single plate of steel under the waterline;  it was a system of layered bulkheads, voids, and plate that was designed to act as a whole to provide mitigation of the effects of torpedoes.  Thus, voids were ‘armor’.  Similarly, the deck armor of a ship was not a single layer of steel but was a layered system consisting of an upper decapping/trigger layer and one or more main layers to further contain and mitigate the blast effects.
 
In addition to physically separated layers, armor often consisted of layers of materials with different metallurgical properties so that the layers might be (to put it crudely) harder or softer, acting in concert to deplete, absorb, and deflect the missile’s energy effects.
 
We’ve also discussed the importance of transverse bulkheads as part of the overall armor scheme.
 
It should also be noted that every bulkhead in every compartment acts as another layer of armor to contain and mitigate damage effects.  Unlike a tank, which only has one compartment and if you penetrate that you’ve likely achieved a kill, a ship has dozens/hundreds of compartments, each acting as a containment unit to limit the extent of damage.
 
It should be obvious, at this point that simply pointing to a weapon and saying that it can penetrate xx inches of steel is completely missing the concept of an actual armor system.
 
WWII – Yet another misconception is the belief that if we apply armor to a ship today we’ll do it exactly like we did in WWII.  I see this argument repeatedly as people argue that modern missiles with diving or pop up maneuvers will easily defeat deck armor because, in WWII, deck armor was less extensive than side armor.  Well, duh!  In WWII, side penetration was the main threat. Don’t you think that if the main threat today is diving missiles that a modern armor designer would take that into account and design the armor scheme to deal with that?  Wouldn’t we put our emphasis on armoring against overhead threats?
 
Data – A final misconception is that there is any data on modern missile’s effectiveness versus armor.  There are only two data points that I’m aware of:  a long ago test of a ?Harpoon? missile against an unspecified battleship armor plate which resulted in nothing more than scratched plate and a widely repeated but wholly undocumented claim of a Soviet ‘shaped charge’ missile warhead that can penetrate xx inches of steel under unknown conditions.  I flat out don’t believe any Soviet claim.  The Soviet’s number one export was exaggerated propaganda.  Thus, there is no credible evidence to assess the effectiveness of missiles against armor and certainly nothing to assess the effectiveness of missiles against an actual system of armor, as we’ve discussed.
 
 
Conclusion
 
We now understand that armor is a system, or scheme, consisting of many components and that the system acts as a whole to protect the ship.  The ability of a missile to defeat or penetrate one component does not invalidate the overall scheme.  As we noted, the purpose of armor is to mitigate the degree of damage from a weapon.  If that mitigation is in the form of immunity (as in the WWII battleship zones of immunity to plunging fire), that’s great but even weapons that penetrate the ship are mitigated by the additional layers of armored bulkheads, void spaces, plates, etc.
 
Before we close out our discussion, it should also be noted that land armor has made immense strides since WWII.  Naval armor has made almost no strides.  There is no reason why some land armor advances couldn’t be adapted to naval use, resulting in even more effective armor.  Newer armor materials and arrangements such as ceramics, polymers, composites, electric armor, sloped armor, spall liners, spaced armor, reactive armor, etc. ought to be adaptable to naval use.  Again, focusing on the claimed ability of a missile to penetrate xx inches of steel is almost a pointless argument.
 
It should be obvious, now, that most anti-armor arguments are based on misconceptions.  There is absolutely no valid reason not to apply armor to every ship, as appropriate for its size, and every reason to do so.
 
Most importantly in the missile versus armor discussion is the recognition that no one has ever tried to design a naval armor system against modern missiles and yet so many people seem convinced that it can’t be done.  Let’s give it a try!  I see no reason why it can’t be successfully done.  Given the staggering, multi-billion dollar cost of even destroyer size ships, it is mind-bending that we don’t armor our ships.