Images have emerged on social media of Philippine military vehicles that have been hastily equipped with wooden armor as a part of their effort to counter attacks from ISIS and Maute held RPGs.  Fighting remains ongoing in the battle for the southern Philippine island of Mindanao, where Philippine President Duterte has declared a state of martial law until the Radical Islamist threat has been eliminated.  These pictures of the Cadillac Gage V-150 armored car employed by the Philippine government’s military show discarded ammunition crates and other bits of salvaged wood secured along the exterior hull of the vehicle – prompting the question: would strapping a bunch of wood to your vehicle actually work to repel a rocket propelled grenade attack?

Well, maybe.

In order to answer that question in a more useful manner, it’s first important to understand how commonly used RPGs work.  The cone shape at the end of the RPG serves as a detonator tip and a form of funnel for the explosive energy released by the weapon when it makes contact with its target.  That explosive energy is known be capable of penetrating up to 180 millimeters of steel armor, making wood an even less likely candidate for successfully defending against such an attack.

However, as seen in use on the Stryker vehicles employed by the U.S. Army Rangers, solid steel armor isn’t always necessary to defend against an RPG.  Many Strykers have been equipped with a cage that surrounds the majority of the outer shell of the vehicle.  When an RPG comes into contact with that cage, it engages the detonator, but because the cage is set a fair distance from the hull of the vehicle, the explosive force funneled through the cone doesn’t reach the vehicle itself with enough energy to penetrate it.

U.S. Army Stryker with RPG resistant cage

The same methodology could actually be employed using wood.  As long as the wood forces the RPG to detonate far enough away from the outer hull of the Cadillac Gage V-150 shown in the images.  However, based on what we can see in the pictures, that seems unlikely.  Much of the “armor” made of discarded wood appears to be no more than a few inches thick, and secured directly to the vehicle’s exterior hull.  At best, that would reduce an RPG’s penetration by a negligible amount and do little to keep the vehicle, or its crew, operational after an attack.

Philippine Cadillac Gage V-150 with wood armor

In order to employ the method shown in these images, the wood would need to be about a foot thick, by some estimates, to dissipate enough of the armor-piercing molten metal to protect the steel walls of the vehicle.  Effectively, a solid wood block would offer the same protection as a thinner piece of wood secured a foot away from its outer shell – as an RPG’s molten explosives would slice through the wood at nearly the same rate as it would empty space.  What’s important is the distance it detonates away from the shell, not what it’s forced to pass through along the way.

Of course, wooden armor isn’t optimal, but when employed properly, it actually could offer some degree of protection against RPG attacks, however, it would never stand up to more advanced anti-vehicle weapons platforms like those employed by full-sized tanks.  Modern armor-piercing weapons used for anti-tank purposes fire tungsten or depleted uranium darts at supersonic speeds.  Such a round would barely notice even a ridiculous looking hunk of wood adorning its target.

Fortunately for the Philippine military, ISIS doesn’t currently possess any such weapons platforms in the region.