If you look at the add-on armour of an Israeli "Zelda" M113 you'll see there is an airspace between the true hull and the outer armour. I'm hardly the first to suggest that such a gap could have earth or rubble piled into this space to improve protection. A vehicle could be airlifted into a theatre and then the additional protection added by the crew once they have landed. As I've said, this is not a new idea.
In World War 2 Sherman tanks were often seen covered in sandbags to protect them from Panzerfausts.
In Vietnam tank crews would place boxes of C-rations on the outside of their vehicles to protect from RPGs.
Some assault guns even used tree trunks as additional armour.
One idea that may or may not have been tried is to place layers of concrete on the outside of armoured vehicles. Cannon like the 25mm Bushmaster may be able to penetrate a T72's armour, but they don't seem to be that effective against building materials. A layer of concrete would act as an ablative protective layer, and crews could easily repair damage with simple tools such as a bucket and trowel. FEEDBACK Ed Sackett writes:- During the early part of WW2, an attempt was made to protect the deckhouses and bridges of British merchant ships by bolting slabs of precast concrete onto them. It proved sadly ineffective: Strafing German planes' machine guns went right through it, shattering the concrete and riddling the compartments it was supposed to protect. 20 mm cannon rounds did an equally devastating job.
An interesting type of armor was developed to replace concrete. It was code-named Plastic Armour (see? I'm not afraid to use a British spelling) and consisted of several inches of asphalt poured hot into forms built around the vulnerable deck structures. It was backed with 3/16" mild steel hardly what you'd call armor plate. The ingenuity lay in what was mixed into the asphalt: clean, sharp, ¾" granite gravel, about 1 part to 2 parts of asphalt. Once the mixture had set the forms were taken away, and this very unlikely stuff proved quite effective at stopping machine gun bullets and even 20 mm shells.
It worked because the gravel tilted on impact, pivoting inside the asphalt matrix and inducing keyholing by the bullet, which spent its kinetic energy going sideways instead of straight in. The mild steel backing flexed inward, spreading the shock over a wide area and thus preventing penetration. When we recall that some German aircraft MGs fired ammo the equivalent of proof loads, that's an impressive level of protection. 20 mm shells were similarly defeated. Strafing attacks suddenly became less lethal, and Plastic Armour was in great demand by bridge and deck crews.
I suspect but can't prove that Plastic Armour was the distant ancestor of Chobham Armour, the successful compound armor used on British and American tanks. An essential component of Chobham Armour is its central layer of interlocking high-strength ceramic inserts, which resist the high temperatures of shaped charges and tilt on impact, inducing keyholing by kinetic rounds.
I realize that you can't build light armored vehicles with Chobham Armour all over them; they wouldn't be light anymore, and anyway you'd have to design the hulls from scratch to make the best use of Chobham technology. But the idea of ceramic inserts can be adapted to the purpose of providing extra protection for vehicles, by bringing back a very old, very good form of armor: brigandine.
Brigandine body armor in its simplest form consisted of two layers of cloth with small overlapping metal plates, usually circular, sewn between them. Additional padding on the inner lining, and lots of brocade, ribbons, buttons, embroidery, and hoopla on the outside, completed the rig. It was light but effective, and remained popular for several centuries.
Let's bring back brigandine for military vehicles. I suggest two layers of fabric, probably a heavy ripstop nylon, with overlapping square tiles of high-strength synthetic ceramic sewn between them. Sewn how? By a single attachment point in their centers, exactly like big buttons, leaving them free to pivot in any direction on impact. Ceramic will defeat and disperse shaped charge jets, and the loose, pivoting arrangement will induce veering in kinetic rounds.
Suits of brigandine can be tailored to fit specific vehicles, but one-size-fits-all panels can also be produced for fast, rough field use. If a panel must be cut to make it go on, I have no objection; that's why I suggest ripstop fabric.
A track or Hummer shrouded in bulky fabric will have a messy, unmilitary look, its sharp lines blurred and its shilouette made indeterminate. Good. That's the way to ride to war on a modern battlefield, where "if you can see it you can hit it."
I don't need to add that vehicular brigandine cloth can be printed in cammy colors, and even made reversible to suit changing terrain. It can also incorporate more elaborate camouflage devices, exactly in the manner of the ghillie suit.
Here is a do-it-yourself upgrade for the M113A3! External storage volume needed The M113A3 is a superb light tracked Armored Fighting Vehicle (AFV) with more internal space than other AFVs for troop gear by its external fuel tanks. However, it does not have external side storage provisions and even the M113A3's volume is soon used up by a Combat Engineer or Infantry unit. This has led to the stretched variant with more internal volume for both Soldiers and gear. However there are some items of Soldier equipment that clearly are too big and shouldn't be kept inside for safety reasons. Mines, demolitions and long bangalore torpedo sections would be better carried OUTSIDE the M113A3, if detonated they would exploded out and away from the vehicle hull whereas if set off INSIDE the vehicle it would be disastrous for the men.
Outside storage bins The M113A3 has bolt-on armor points that are currently not being utilized. These could be used to bolt on a metal framework with thick metal mesh to create storage area all along the length of the vehicle. These storage bins could be created by local units as per TM specifications for very low cost. The long nature of the bins would allow long bangalore torpedo sections to be carried securely outside the vehicle, stretchers, spine boards for Medical M113A3s, as well as a huge supply of land mines, ammunition, demolitions and/or even Soldier rucksacks. Appliqué armor is what appliqué armor does We realize the powers-that-be hate the M113A3 and have consistantly blocked attempts to buy the appliqué armor that was always intended for it to have to protect it from RPGs and weaponry up to 30mm autocannon. Do not list this side benefit of external storage bins if these biased individuals will veto the local modification. Perhaps later on Soldiers will figure the following out or we could "discover" the application and advocate it after the storage bin becomes officially accepted. Ammo cans and storage bins could be filled with dirt, sand or even concrete to bolster armor protection as the situation demands.
But in Vietnam, Soldiers erected chain-link fencing around their M113A1s and M48 tanks to pre-detonate Rocket Propelled Grenades (RPGs). In Chechnya, Russians today have placed wire screens around ther vehicles to defeat RPGs. The metal mesh M113A3 storage bins would act as RPG screens. This is just the beginning.
Its also possible to add a layer of sandbags or MRE cases filled with dirt into the M113A3 side storage bins to add additional armor protection---appliqué armor by field expedient. A layer of sandbags stops all 7.62mm/.30 cal MG bullets cold. Combined with the M113A3's 1.5 inch thick hull armor and spall liners, you would have 4-6 layers of protection:
1. Outside storage bin screen: pre-detonates RPGs, breaks up bullets 2. Sandbags absorb shaped charge effect of RPGs/ATGMs, decelerate bullets, put some on the driver's floor area 3. Hull armor hard plate stops fragments/bullets already slowed that are not stopped by previous layers 4. Spall liner stops the fragments (if any) that penetrate beyond this
The cumulative effect of the storage bins would be greater mission effectiveness by greater amounts of weaponry, equipment being carried and greater Soldier protection via the side benefits of adding outside layers to the vehicle itself.
5. Add titanium appliqué armor to stop 30mm autocannon fire 6. Attach Explosive Reactive Armor (ERA) to defeat hollow-charge RPGs and ATGMs