Key Point: Mortars were artillery pieces used to fire explosive shells at a high angle onto targets such as fortifications from specially designed ships.
Here you will see a discussion on mortars as a naval weapon. When you think of mortars you normally think of them being used on land. But weirdly enough mortars were an important weapon in the “Age of Sails”. In this article, you will see what were mortars and how they were used by ships to destroy targets.
So, let’s start from the beginning. What are mortars? And how were they used by ships?
Mortars were a type of indirect fire weapon that use a high-angle trajectory to lob explosive shells onto targets. During the Age of Sail, mortars were mounted on specialized mortar boats to support naval operations. These vessels were used primarily for shore bombardment, with the mortars being used to attack land-based fortifications and other targets.
As you can see naval mortars were mostly used against land-based targets. But why not attack other ships with it? We will examine that a little later. But for now, let’s continue with the origin and history of mortars as a naval weapon.
Origin Of Mortars In The Navy
The origin of mortar use can be traced back to the Dutch. More specifically the 17th-century Dutch. Back then they were a rising naval superpower and were actually the first to employ mortars on ships. This is a rough approximation of what that looked like.
The Dutch quickly realized how useful having these types of ships is to bombard a besieging city or fortifications. And they were not the only ones. By the 18th century, mortar vessels were a common sight in naval fleets, and were used to great effect in several major battles. This leads us to …
A Famous Naval Battle Where Mortar Ships Were Used
One of the most famous uses of mortars on ships was during the Siege of Gibraltar in 1779-1783. This is when a British fleet used mortar vessels to bombard the Spanish defenders of the fortress. The mortars were able to fire shells over the walls of the fortress. Which caused significant damage and contributed to a British victory.
And the Brits to this day hold Gibraltar. Now, let’s take a look at the specs of mortars used on ships through the centuries.
Dimensions And Specifications Of Mortars Throughout The Centuries
Below you can see a range of calibers and ranges of mortars through the centuries. Of course, many navies had different calibers with different ranges. And as you will notice as the years progressed technology has gotten better. Which meant the ranges improved as well.
17th century
- Mortar shells typically weighed between 10-30 pounds
- The range was limited to a few hundred yards
- Mortars were often mounted on small, lightly armed vessels with a narrow, deep hull
18th century
- Mortar shells grew larger, ranging from 30-200 pounds
- Range improved to around 2-3 miles
- Mortar vessels grew larger as well, with wider, flatter hulls to accommodate heavier guns
19th century
- Mortar shells continued to grow in size, with some weighing over 300 pounds
- Range increased to as much as 5 miles or more
- Mortar vessels became less common, with mortars being mounted on other types of ships or on shore batteries
Those were the average dimensions and ranges throughout the centuries. Now, let’s examine exactly how the navies of the era put naval mortars to use.
How Mortars Were Used In Naval Battles
Mortars were used by navies as a way to effectively bombard coastal cities and fortifications. The mortars enabled ships to send highly explosive projectiles at a high arch that enabled them to bypass strong walled fortifications.
Why shoot at a wall when you can shoot over it, and caused damage inside the city/fort? It was an effective weapon to bypass a stronghold’s fortifications and go at them from another angle.
Which also begs the question. Since mortars are effectively cannons and they were placed on ships … were they ever used to fire at another moving ship? Well … let’s find out.
Were They Ever Used To Fire At Other Ships?
No, naval mortars were not generally used to fire at other ships. Here is why. As you know the projectile from a mortar traveled at a high arc toward its target. Meaning it took a while for the projectile to reach the destination.
And firing a projectile that takes its time toward a moving target, such as a ship, makes zero sense. The ship was usually in motion so by the time a high-arching projectile reached the target the ship would already be a safe distance away.
It simply was not practical to use mortars to attack other moving ships. They had other more effective cannons to achieve that.
This leads us to another question. Why did mortars stop being used?
Why Did Mortars Stop Being Used?
The decline of mortar use on ships came about because of advances in gun technology. It’s quite simple. As naval guns got more advanced the projectiles they fired were more powerful and more explosive. And of course, could be fired from greater and greater distances.
From a cost-benefit analysis, it made much sense for navies to build a ship that could fire at other ships and at coastal fortifications rather than making a separate class of ships to fire at fortifications and other classes to battle other ships.
Similar to what happened with grappling hooks, which were also outdated due to advancements in naval gun technology.
In Conclusion
Thank you for taking the time to read this article. I hope you learned a thing or two about this fascinating piece of naval weaponry. I hope to see you at the next article. I suggest taking a look at this article where I discuss the ship of the line and its use
Take care!
Source: “Naval Warfare in the Age of Sail: War at Sea 1756-1815” by Bernard Ireland