How Sapping Was Used In Sieges

Key Point: Sapping involved digging trenches or tunnels toward enemy fortifications to undermine walls. This method allowed attackers to approach fortifications with cover, creating openings for breaching.

This article will cover sapping. And how it was used in sieges. This siege weapon proved to be remarkably effective in sieges through the centuries. That is why we are looking at how sapping was used to bring down walls of cities and fortifications.

Now, before we continue forward, we must make one thing clear. What is sapping? Let’s see what that is.

Sapping in sieges is used to undermine the walls of cities and fortifications. It involved digging a tunnel or a series of tunnels underneath the wall and then collapsing it to cause the wall to crumble. Sapping was an effective way to breach fortifications, as it was difficult for defenders to detect and prevent the digging of tunnels. It has been used in many historical sieges, including during the American Civil War and World War I.

That was a short introduction to sapping in sieges. Now you get to see this wonderful history behind sapping in the next segment.

The History Of Sapping In Sieges

The origins of sapping can be traced back to ancient times. This is a time when armies would use rudimentary tools such as picks, shovels, and axes to dig tunnels underneath walls. The ancient Greeks, Romans, and Persians all used sapping in their military campaigns.

A little later, during the Middle Ages, sapping became a more sophisticated tactic. Engineers developed new techniques for digging and tunneling, and armies began using specialized tools such as mining picks and bore hammers.

The Byzantine Empire was particularly known for its use of sapping in sieges. And their engineers even wrote detailed treatises on the subject.

Here is the weird part …

With the advent of gunpowder and cannon in the 15th and 16th centuries, sapping became even more important. Who would have thought?

Sapping became an even more important tactic in siege warfare in the gunpowder era, as it allowed attackers to bypass thick walls and other defensive measures that were designed to withstand cannon fire. Sapping was a slow and difficult process.

But it could also be highly effective when used correctly. During the American Civil War, both Union and Confederate forces used sapping extensively. And many of the most famous sieges of the war, such as the Siege of Petersburg, relied on sapping to breach Confederate fortifications.

Here is one of the more famous sapping operations of the 20th century.

Famous Sapping Operation Of The 20th Century

During World War I, the Allies carried out a sapping operation known as the Battle of Messines. Here is the crazy part.

They dug a network of tunnels and mines beneath the German lines for several months. The goal being planting a series of massive explosives beneath the German fortifications.

On June 7, 1917, 19 mines were detonated simultaneously, creating a massive explosion that destroyed the German fortifications and killed an estimated 10,000 German soldiers. The Allies were able to advance and capture several key positions.

That just goes to show that sapping was an effective weapon that was used even in modern warfare. So, with the history lesson out of the way, let’s see how it actually worked. The next segment details how an average sapping operation worked.

How Sapping Worked In Sieges

The process of sapping involved digging a tunnel, or “sap”, beneath the target. The diggers digging the tunnel were called the “sappers”. They would begin by digging a small hole at a safe distance from the target, then gradually extending the tunnel closer to the target under cover of darkness or smoke screens.

Once the sappers were close enough to the target, they would begin to dig a chamber beneath it. They would then fill the chamber with explosives, such as gunpowder or dynamite. The explosives would be ignited, creating a massive blast that could breach the walls or destroy the target altogether.

The sappers faced numerous risks during the operation, including:

  • cave-ins
  • suffocation from lack of oxygen
  • detection by the enemy

To mitigate these risks, they would typically work in small teams and use specialized tools, such as wooden shovels and metal probes, to dig quietly and efficiently. Sapping was a slow and dangerous process, but it was often effective in breaching the walls or fortifications of a target and allowing the attackers to gain entry.

How You Can Counter It

The defenders of a fortress or city had several options to counter sapping during a siege. One method was to dig their own counter-sap. That was a tunnel that intersected the enemy’s tunnel and allowed the defenders to engage the sappers in close combat.

They could also use listening galleries. Those were small chambers dug into the walls or floor of the fortress, to detect the sound of digging or other activity by the sappers.

Another tactic was to flood the enemy’s tunnel with water. Either by diverting a nearby river or by digging a well and filling it with water. This would not only flood the tunnel but also drown the sappers.

The defenders could also use mines or countermines, explosives placed in their own tunnels or at strategic locations, to destroy the enemy’s tunnel or cause a cave-in.

They could also use sound detectors, such as listening tubes or stethoscopes, to detect the sound of digging or movement underground. If the defenders detected the enemy’s tunnel, they could use hot oil or boiling water to pour into the tunnel, killing or injuring the sappers.

As you can see from the above countermeasures put in place being a sapper was dangerous. No less so, than being a foot soldier. A cold, dark place that could flood or blow up was no fun to be around.

In Conclusion

Thank you for taking the time to read my article on how sapping was used as a weapon in sieges. I hope you learned a thing or two. If you wish you can continue reading about siege weapons whose purpose was to bring down walls by taking a look at this article. There I discuss siege hooks. And how they were used to attack walls.

Or take a look here at how war elephants were used in sieges.

Take care!

Sources: “The Art of War in the Middle Ages, A.D. 378-1515” by C.W.C. Oman