Plastic Armour

[fastmongrel]

At the start of the war the British Admiralty was concerned about armouring Merchant Ships and small Naval vessels against machine gun and cannon fire from German aircraft. Armour plate was in short supply so other armouring methods were tried, initially Concrete paving slabs 6 inches thick were tried but proved to be worse than useless because armour piercing bullets would go through it easily and blow out damaging shrapnel. A keen amateur inventor Lt Edward Terrel Royal Naval Volunteer Reserve came up with what became known as Plastic Armour made up of Granite chippings evenly mixed into Bitumen and cast into moulds with a mild steel backing plate. The Granite chips broke up and diverted AP rounds the Bitumen slowed the bullet fragments down and the Mild Steel plate caught any fragments that made it through the Plastic compound. The road building industry was used to make the Plastic part because wartime had cut the use of Bitumen for road building and repairs.

The Plastic name came from the original meaning of Plastic something flexible that can be moulded rather than the modern useage of a Polymeric material.

The cast panels were bolted into position with studs and nuts.

Below can be seen how well the sacrificial armour worked

Edward Terrel

 

[yulzari]

At the start of the war the British Admiralty was concerned about armouring Merchant Ships and small Naval vessels against machine gun and cannon fire from German aircraft. Armour plate was in short supply so other armouring methods were tried, initially Concrete paving slabs 6 inches thick were tried but proved to be worse than useless because armour piercing bullets would go through it easily and blow out damaging shrapnel. A keen amateur inventor Lt Edward Terrel Royal Naval Volunteer Reserve came up with what became known as Plastic Armour made up of Granite chippings evenly mixed into Bitumen and cast into moulds with a mild steel backing plate. The Granite chips broke up and diverted AP rounds the Bitumen slowed the bullet fragments down and the Mild Steel plate caught any fragments that made it through the Plastic compound. The road building industry was used to make the Plastic part because wartime had cut the use of Bitumen for road building and repairs.
The Plastic name came from the original meaning of Plastic something flexible that can be moulded rather than the modern usage of a Polymeric material.

A cunning use of materials. The bullet would either enter the bitumen or the stones would divert it into the bitumen, then the energy of the bullet would be expended trying to move the adjacent stones sideways into the bitumen/stone mass instead of just penetrating. Thus being squeezed to a stop. Concrete armour works if the personnel/vulnerable items are behind the concrete. The energy reflection in concrete goes outwards through spreading cracks in the brittle cement matrix so the spalling flies away from the armoured object. No use if it them hits assorted personnel and important bits of the ship. Steel armour reflects inwards. Hence HESH rounds slap a pat of HE on the outside of a tank and the interior is treated to several kilos of scabbed steel flying off the inside wall to the detriment of the occupants.