mortar vs cannon question

[Milkmaster]

I have asked this question a couple of times with no real decisive answer given, so I am going to try again...

What decides whether a piece of artillery is classified as a mortar or a cannon? Are those two terms interchangeable?

I see pictures of old mortars from the civil war era that tend not to have long barrels and are more of just an indention into a piece of iron to put in powder & launch a round over to the enemy. Of course cannons are smooth or rifled bores for aiming purposes but could do the same as a mortar. Is that the actual difference between the two when it comes to categorizing them?

I need a few of you good miltary guys to 'splain it to me please. Any links you might have on the question would be welcome.

Thanks for your reply.

 

[rcmodel]

In simple terms:
A mortar is only capable of Indirect fire.
As in lobbing shells up over a fortress wall or hill at a target hidden behind them.
A mortar is incapable of Direct fire.

A cannon or howitzer is capable of both Indirect fire, and Direct fire.
As in lobbing shells over the hill until you can see the whites of their eyes.
Then bringing the elevation down and firing directly at'em!

Another distinction of modern mortars & cannons is:
The mortar is a small light man portable weapon.
A cannon or howitzer is a wheeled or tracked weapons system too big to man carry.

BTW: A recent development in modern computer controlled cannon is the ability to use both indirect & direct fire at the same time.

By firing the first rounds of a fire mission indirect in very high trajectorys, and the later rounds in direct fire, all the rounds land on the same target at the same time.

rc

 

[Riss]

In other terms a cannon may also be a high pressure, high velocity round like a rifle. While a mortar is lobbing a large heavy object slowly at lower pressures. In modern mortars the mortar is simply a tube, while the mortar shell has its own contained lifting charge and stabilizing fins, a cannon works like a rifle, shell casing and bullet in the tube.

 

[KenWP]

Would be a lot of work to use a cannon as a mortar as you would have to lower it to load it then raise it back into the fireing poistion. That or use a ladder to load it upright.

 

[w_houle]

Mortar: very short barrel, to the point of looking like a mortar (bowl).
Cannon... I'm working on that.

 

[rondog]

For fun, do a Google search for "hunting feral cats with a coehorn mortar".

 

[4v50 Gary]

What makes the difference? Well, it's the trajectory. While you can do indirect fire with howitzers, the mortar is a high trajectory weapon meant to destroy or harass a concealed foe.

Black powder mortars came into use in positional warfare. The high trajectory allowed one to literally drop shells atop of one's foes. This came in very handy during 18th and 19th Century sieges when you couldn't see the other fellow because he was in a trench that was generally below ground level or hidden from view by a wall of dirt-filled gabions with fascines piled atop. For the defenders, one would try to drop a shell on the sappers as they dug their approach trenches. For the besieger, they could drop shells atop of defending artillery or riflemen who were sheltered behind the safety of sandbags.

For more information on this type of warfare, goggle Sebastian Vauban. If you are on the East Coast near Governor's Island at New York city , Fort McHenry (Maryland), Fortress Monroe (Yorktown Peninsula in Virginia), you can visit a 18-19th century fort that was designed with Vauban's principles in mind. Talk to the ranger about sieges during the period.

 

[tkendrick]

Don't know that I can answer your question about what makes a difference, but I can tell you this.

Somebody shoots artillery at you, whether canon or howitzer, and you generally can hear it coming.

Mortars, you generally don't know they're coming 'til the rounds start blowing up in your face.

At that point, the pucker factor is very high.

 

[goofy grape]

At present time, a mortar is a man portable weapon and is used by Infantry troops. Artillery is either towed by vehicles or is Self-Propelled. Artillery used by the U.S. is 105mm(towed),155mm(Self-propelled) or a MLRS (Multiple Launch Rocket System). A mortar is 81mm if I remember correctly. Mortars are used for indirect fire only and are smooth bore. Artillery pieces can be indirect or direct and have a rifled barrel. If push came to shove, the Self propelled artillery, which is an M109A6 can function as a tank (armor).

To answer your question, no, a mortar cannot be classified as Artilery. It's an Infantry weapon. By the way, I don't suppose Thomas Espy has shown up has he?

 

[rcmodel]

Not all mortars are smoothbore.

The "Four-Deuce" (M30 107 mm - 4.2 inch Mortar) we used during Vietnam were fully rifled and used an expanding base plate on the shell to engage the rifling.

rc

 

[Jim K]

Mortars are intended primarily for reaching an enemy in a defensive position, such as behind a fortress wall or in deep trenches. They are usually used with shells designed to explode as they descend, showering the enemy with internal projectiles and shell fragments. That is why mortar projectiles are often called "bombs" even today.

That is the meaning of the phrase in The Star Spangled Banner" about "bombs bursting in air". British "mortar ships" were firing large mortars at Ft. McHenry; the bombs were fused to go off in the air. ("The rocket's red glare" refers to British use of Congreve rockets, also fired from ships called, appropriately if confusingly in the modern world, "rocket ships.")

Jim

 

[rocky branch]

I have dropped quite a lot of mortar rounds down the tube.
60s, 81s, and 4.2s. Also a couple 82s.
I have been on the recieving end of even more.

These all have impact fuses.
Some of the Commie models they tossed at us had chemical delays, some up to 24 hours.

Another aspect is that mortars make no sound inbound.
Sometimes you can hear them leaving the tube.

An interesting experience is having some guys out looking for them and they report, "They just dropped three!"
Then you wait....

 

[BADSBSNF81]

Artillery has been, and on occasion is still transported by mules.

 

[PandaBearBG]

Mortars are more a infantry crew serve weapon, man portable, maybe excluding the 120's, never used those. Cannons I'm guess towed or vehicle assisted.

I've fired the 81's and 60's and while they do fire indirectly the smaller 60's you can attach a hand firing device (I can't remember what it was called, like a big ole clacker you attach to the end) along with an ugly kitchen mitt to hand fire for direct fire. I have never actually done it with live rounds but it is possible and we learned how to do it once. I stuck with the 81's.

w_houle - I don't understand by what you mean by "Mortar: very short barrel, to the point of looking like a mortar (bowl)." 81's are pretty long there.

Big heavy 81's are meant to be transported by Humvee, but we always seem to have to hump them. Short rounds suuuuuuuckk.

 

[fineredmist]

He is referring to early 1800s and civil war era mortars, for example a 13", 1861 model had a bore diameter of 13", a bore lenght of 35". and a overall length of 54.5". That would give the impression of a short barrel. This particular mortar weighted 17120 lbs, fired a 20 lb. charge and had a range of 4200 yards.

 

[w_houle]

w_houle - I don't understand by what you mean by "Mortar: very short barrel, to the point of looking like a mortar (bowl)." 81's are pretty long there.

Yeah, that hasn't applied in quite some time.

My meaning was more of the old idea rather than modern. I was looking for the sheet that I had that gave a specific name and length for each gun. It had the cannon as a specific length of ship gun usually found on the upper mid decks.

 

[4v50 Gary]

As the original question is black powder oriented, it has been moved to the blackpowder forum.

 

[Snaggletooth]

Mortars vs canon

Mortars are high angle of fire weapons used primarily on troops in the open or in trenches. There are several types of ammo fuses for the mortar. PD (point detonating) explodes upon touching an object that is in the way after the projectile leaves the muzzle. The shell is dropped into the muzzle and the primer strikes the firing pin, detonation occurs and the increments (bags of powder) attached top the base of thr round are ignited. There is a bore riding safety pin that has been released by "set back"action from the change of direction in the projectile. Upon clearing the muzzle of the mortar the safety pin is expelled and the round is armed Mortar fire is not as accurate as cannon fire and landing in 15 yards is considered a hit. 60 mm and 81mm are crew served weapons are carried by the crew. 4.2 ch are towed and are considered artillery. Company commanders use the 60 mm in their tactics. 81 mm are used by bn commanders and 4.2 are for useby regimental commanders Fire direction centers are used to direct the fire and all weapons , either mortar or artillery can be brought to bear on the target Other types of fuses for the rounds are delay and vt. Delay fuses impact and explode 1/10 second later. Vt are set and can be made burst in the air over troops in the open or in trenches. Delay fuses are used as bunkerbusters. That is the way it was in 1950. Things change.

 

[theotherwaldo]

The primary function was, and still is, to deliver indirect fire on opponents that are under cover or behind defenses. Up until the 1830s the big advantage of the mortar was that it could deliver explosive payloads on target, as well. Other forms of artillery could not.

Massive mortar shells were required because they had to take the stresses of firing and landing while protecting both the explosive payload and the simple fuse that ignited the explosive charge. Smaller shells simply didn't allow enough room for enough protected fuse. So shells were big and the cast metal mortars were even bigger.

Small coehorn mortars existed, but they filled the niche that is held today by the grenade launcher. They and their larger brothers had the distressing habit of blowing up if the hand-lit shell fuse burned down before the mortar went off.

Congreve rockets were an attempt to produce an explosive projectile without dragging around a massive mortar, but they were pretty much a failure.

Improved patent fuses allowed the shells to get smaller and better metallurgy allowed mortars to get small enough to be man-portable.

Now, when mortars are mentioned, it's small, infantry weapons that come to mind rather than the massive siege engines of bygone days.

 

[Milkmaster]

Thanks waldo... that is more along the lines of what I was aksing in the original question. I am gathering from the responses that a mortar simply launches a charge over top of the opposing force and detonates later once it has reached the enemy. The cannon is more direct fire although can sometimes be used in similar fashion as a mortar depending on the round chosen.

Thanks for all the replies so far. Been quite a history lesson.

 

[PandaBearBG]

AH fineredmist, I had seen a picture of one of those old mortars before, good info, very interesting view of how mortars have progress. Got alot of history in the combined intellect of THR. Nice work fellas.

 

[rondog]

In "Saving Private Ryan", wasn't there a scene during the final battle to protect the bridge where they were taking mortar rounds, whacking them against something, and then hand-throwing them? What was that all about? Or was I just imagining things....

 

[Sunray]

Hi, Milkmaster. It's a trajectory thing. A mortar round, modern or otherwise, goes up and comes back down in a high, arc with a relative low velocity and a reltively short range. Mortars didn't use cannister or grape shot either. Not used against the PBI until W.W. I's trench mortars. 19th Century and earlier mortars were siege weapons. Big, hollow, iron balls filled with BP and a fuse.
Cannons could be siege weapons or field guns. A cannon round's trajectory is flatter with a higher velocity. Much longer range, several miles, using different ammo for different targets. Cannister or grape shot, big shotgun rounds, was used against infantry and cavalry at close range. The typical cannon ball, a solid ball of iron, was used for longer ranges. A round ball could go through several lines of infantry, killing as it went. And, depending on how hard the ground was bounce off the ground. It didn't stop causing casualties until it stopped. A 24 pounder fired a 24 pound iron ball, about 6" in diameter, at around 1400 to 1800fps.
Some ball shot was explosive. Literally a hollow iron ball filled with BP and a fuse. The fuse could be cut to cause the powder charge to explode when desired.

 

[desidog]

Additional to the correct comments on historical, eg BP, cannon and mortar above; If you've been looking at old pictures, you may also have been looking at cannonades...short-barreled cannon that were mainly used in naval applications for close-in work, when accuracy was not an issue. The shorter barrel reduced the overall weight, allowing a ship to carry more armament. Commonly they were referred to as "smashers."

 

[Das Jaeger]

Very good point ,

and , they were used to disable rigging is my understanding to disable the ships so they could board them later ? Very rarely did they want to sink a ship , they wanted to Plunder it and enslave the crew .

Jaeger