Fougasse (weapon)

A fougasse (UK: /fuːˈɡæs/, US: /fuːˈɡɑːs/, French: [fuɡas] ^ⓘ, in Italian and Maltese foggazza) is an improvised mortar constructed by making a hollow in the ground or rock and filling it with explosives (originally, black powder) and projectiles. The fougasse was used by Samuel Zimmermann at Augsburg in the sixteenth century, referred to by Vauban in the seventeenth century, and well known to military engineers by the mid-eighteenth century. Notable use of permanent fougasse installations intended for coastal defence were carved into the limestone by the Knights of St. John on Malta. This technique was used in several European wars, the American Revolution, and the American Civil War. The term is still used to describe such devices.

The normal method of firing was to use a burning torch or slow match to ignite a saucisson (French for "sausage", a cloth or leather tube waterproofed with pitch and filled with black powder) leading to the main charge. This had numerous disadvantages; the firer was obvious to the attacking enemy, and had to run to get clear after lighting the fuse. The black powder was also very susceptible to moisture, and might not work at all. In 1573 Samuel Zimmermann devised an improved method which incorporated a snaphance (or later, flintlock mechanism) into the charge and connected its trigger to the surface with a wire. This was more resistant to moisture, better concealed and enabled the firer to be further away. It also enabled the fougasse to be tripwire activated, turning it into an anti-personnel fragmentation mine.

In a letter to his sister, Colonel Hugh Robert Hibbert described such a weapon employed during the Crimean War:

These wretched Russians have discovered a new system of annoyance which would be well worthy of invention by Franky [their brother] and which consists of a series of small mines or barrels of gunpowder let into the ground between our works and theirs, and a little tin tube running along the ground a few inches above it, two or three feet long, which tube is filled with some composition which explodes immediately on being touched, so that any unfortunate meandering along the grass without knowing why, suddenly finds himself going up in the air like a squib with his legs and arms flying in different directions. We have had many men blown up by these things and the grass being so long one cannot see the tube at all. The technical name is "Fougasse". Franky will know what they are I daresay. The ground between our old trenches, and the Russian ones that we took the other day is full of them. At night you hear a sudden explosion and you know that some wretched fellow has been crossing from one trench to another, on private speculation to see what he could get, has trod on the tube and been blown up. I often think how the Russians must laugh when they hear these things going up at night in all directions, they must know well what it is.

There are several variants according to the material projected by the explosion.

The most common type in early use was the stone fougasse, which was a hole simply filled with large rocks and bricks. When fired, it would scatter a hail of fast-moving stones across the area to its front. Large stone fougasses might hold several tons of rubble and as much as a hundredweight of powder.

The shell fougasse was loaded with early black powder mortar shells (essentially a large version of an early black powder hand grenade) or incendiary "carcasses". When fired, the powder charge would throw out the shells and ignite their fuses, so the projectiles would be scattered across the target area and then begin exploding, filling the area with fragmentation or flame from all directions in an effect similar to a cluster bomb.^{[citation needed]}

A flame fougasse was a similar weapon in which the projectile was a flammable liquid, typically a mixture of petrol and oil. The flame fougasse was developed by the British Petroleum Warfare Department in response to the threat of German invasion during World War II.