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efreysson
05-05-2014, 01:54 AM
I've reached a point in my fantasy WIP where an army is trying to invade a walled city. They only have a few days to do so before the city gets reinforcements so they don't have time for long-term strategy such as starving it into submission or launching infected corpses. Besides, for plot-reasons I need the army to storm the wall several times.

I'm wondering how catapults were actually used, in terms of accuracy and targets. Could the defenders try to take out the besieging catapults with well-placed rocks? And how much would it take to breach a wall with catapults?
I want siege towers and ladders to feature in the battle, but I also want the factions to fight smart.

Mikilao
05-05-2014, 02:11 AM
If they don't have much time and need to siege the city did they already have the catapults? Are you trying to build them on the battle field? that takes wood and engineering plus time. if they didn't have the catapults then they should go with hooked ladders and grappling hooks. Maybe large hooks and oxen to tear down the walls. In a pinch they could melt fat of animals into oil and use jugs to light the wall on fire. walls were made of stone but held together with dung, mud and straw. Very susceptible to fire. just a few ideas

ULTRAGOTHA
05-05-2014, 02:18 AM
What kind of catapult are your people using?

Does the city have catapults, too? How thick are the walls? What kind of payloads are available inside the city? How well prepared were the citizens to withstand and repel a siege? What kind of supplies do they have?

What kind of payloads are available outside the city? How well trained are the besiegers and how many/what kind of catapults do they have? What kind of defense do the besiegers have against fire arrows and oil used against the siege towers and the people in them?

If the besiegers have catapults, ladders and siege towers they have a lot of well-organized logistics and quartermasters. That stuff takes horses/oxen and carts and feed and people to assemble them. It takes roads that can handle the load. Or, alternatively, it takes a lot of trees, metal, rope, weights, carpenters, blacksmiths, ropemakers, engineers and time.

How Stuff Works (http://science.howstuffworks.com/transport/engines-equipment/question127.htm)

Physics of various types of Catapults (http://www.real-world-physics-problems.com/catapult-physics.html).

Book from NOVA: Medieval Siege (http://www.real-world-physics-problems.com/catapult-physics.html)

Medieval Siege Weapons (http://www.amazon.com/gp/product/1841762350)

benbenberi
05-05-2014, 02:37 AM
The effectiveness of catapults will depend on a number of factors, inc. how big the catapults are, how much ammunition (i.e. really big rocks of appropriate shape & weight) they have available, how good the engineers are at establishing range & trajectory so they can hit their chosen target consistently, how well-built the defending walls are, and how good the catapult commanders & siege engineers are at picking the most vulnerable point to get the effect they want. (Angles in the walls were typically the weakest spots structurally, and also the hardest for the defenders to cover. That's why fortifications favored long straight walls and curves, till gunpowder changed the tactical dynamic.) If they're experienced, well-prepared, and facing a weak enemy, this can get a quick result. If not, not.

Alternatively, they can use the catapults as a distraction, & while the defenders are focused on that, send in miners to blow a hole in the wall somewhere else.

When catapults are used, it helps if they're big enough they can stand out of range of effective counter-fire from the walls. Defenders can harass the catapult crews with arrows & potentially set fire to it, but pre-gunpowder fortifications generally didn't include any defensive equipment capable of doing real damage to something like a catapult that could be used from a variety of positions.

The best way to win a siege quickly, of course, is by treachery, i.e. getting somebody on the inside to open up. This can be combined with any of the above.

blacbird
05-05-2014, 02:41 AM
In Medieval times, addtional to the catapult was the trebuchet, a different and possibly more powerful mechanism. The nature of the walls being targeted are pretty important, too. You might want to do a bit of historical research into fortifications and siege weapons of the time. Ultragotha's post above is a good place to start.

I also understand that what might be the first usage of biological warfare took place via the besiegers hurling rotting animal carcasses over the walls into the fortifications.

caw

caw

snafu1056
05-05-2014, 03:08 AM
Look into Osprey's line of military history books. They have several on seige engines and fortifications from different times and places. And with lots of nice pictures.

Depending on how advanced your army is you can also look into early firearms, specifically early Chinese explosives and firearms. Weapons like the fire-lance, bombs, etc. They started appearing around the 13th century.

Jo Zebedee
05-05-2014, 03:27 AM
Ex-medieval castle tour guide here...

The problem with attacking a castle is, once you're attacking the walls, there is no easy and quick way to do it - that's why they're built the way they are. Sorry.

Quick ways of taking a castle probably include having someone inside it. Even then, a full-frontal assault is hard. If an attack happened and the portcullis brought down in a hurry it takes days, if not weeks, to get it raised again because the rope will have been cut.

Attacking the walls with hooks and siege engines is probably quickest but, as has been pointed out, you have to get them to the field which means the castle, in its raised position, holds a view over what's happening.

Sappers are worth thinking about - but most castles have the foundations from hell to withstand this.

A few thoughts - a breach in defences? The castle I worked in withstood an attack with 50 foot of wall missing because the attackers didn't know. The postern gate could be utilised in an inside job. But, aside from subterfuge, any quick win is going to be hard to convince of.

Edit - oh and square castles are more susceptible than round to catapults cos you can lop a wall off. :)

wendymarlowe
05-05-2014, 04:09 AM
If they don't really care about the people inside, flaming arrows can be an effective tactic (depending on the time period and how much exposed wood/straw there is).

Avatar_fan
05-05-2014, 04:23 AM
Sieges tended to be long as the main way to bring a castle down was through starvation. There's a story in the Middle Ages where the poor civilians were caught between the besiegers and the defenders. The besiegers wanted the civilians to enter the castle and use up their food and supplies but the defenders wouldn't let them in so those people were caught in the middle and just starved to death. It was an incredibly cruel time.

For your story, you could try treachery kind of like the Trojan Horse. Try to find a way for them to trick the people inside the castle. Or maybe a secret entrance. There's another story in the Middle Ages where a group of knights got inside the castle through the latrine. They didn't smell good, but they took the castle!

Telergic
05-05-2014, 05:00 AM
Obviously there is enormous variability in defensive wall strength, and also in the force and quantity of catapults the attackers may have brought with them. The defenses may range from flimsy, knocked down in the first salvo, to well-nigh impregnable, requiring months or years of tunneling to undermine.

Because of this enormous variability, OP can just decide what the desired outcome may be and describe things that way.

From the notion the attacker doesn't have much time, I can speculate they probably don't have overwhelming force. If the city defenses are strong, then a few days of rock-throwing might not suffice to do any noticeable damage. In that case, the attacker would have to either decamp or assault.

An assault involves going over the walls in the face of defensive fire, and will result in enormous casualties unless some kind of trick is used. For example, Belisarius is supposed to have gone through an aqueduct tunnel on one of his campaigns. Going over the walls in an assault may require anything from ladders to wooden siege towers, or may require people to just pile dirt and debris up under the walls, depending how high they are and how well the attacker is equipped. Obviously this last choice will be extremely dangerous for the workers.

Edit: Oh yeah, if the defenders have better siege weapons with longer range than the attackers, as OP suggests, then the attackers might as well go home unless they assault immediately because of course the defenders will target any siege engines that approach.

Vomaxx
05-05-2014, 12:17 PM
Perhaps the lord of the city has neglected routine maintenance and tuck-pointing, so that a couple of good hits will cause some mortar to crack and part of the wall to tumble down?
Catapults can breach a wall--make a hole in it--but not knock down an entire wall. Also remember that the rubble from the breach will pile up and have to be climbed over by the attackers.
I don't think that "counterbattery fire" from engines within the city should be too much of a threat.

Telergic
05-05-2014, 06:41 PM
Posters should read the OP and note this is a city, not a castle we are talking about. Obviously the wall surrounding a city is much more likely to be breachable than a castle wall, and moreover there will be some substantial delay in moving forces around from point to point. Still, it's possible for a city to have walls that are strong enough to be essentially unbreachable by pre-gunpowder weapons. But a sufficiency of defenders is also required because of the circuit length of the walls.

snafu1056
05-05-2014, 07:22 PM
For sure. There have been some long seiges in history. It took Khubilai Khan five years to finally crack the town of Xiangyang in China. In the end he had to call in expert seige engineers from the middle east who built him a "super catapult" that could hurl massive boulders great distances and smash pretty much anything. It worked. It demoralized the defenders into surrendering.

Maybe you should consider having your army come up with some kind of super weapon. Because if theyre just using convention tactics, there arent too many ways to crack a fortified town that quickly.

efreysson
05-06-2014, 02:10 AM
If they don't have much time and need to siege the city did they already have the catapults? Are you trying to build them on the battle field? that takes wood and engineering plus time. if they didn't have the catapults then they should go with hooked ladders and grappling hooks. Maybe large hooks and oxen to tear down the walls. In a pinch they could melt fat of animals into oil and use jugs to light the wall on fire. walls were made of stone but held together with dung, mud and straw. Very susceptible to fire. just a few ideas

The idea is they brought light catapults along on wheels and start building larger ones in camp as the siege goes on.

Thanks for the suggestions. I hadn't realised that about setting the mortar on fire.


What kind of catapult are your people using?

Does the city have catapults, too? How thick are the walls? What kind of payloads are available inside the city? How well prepared were the citizens to withstand and repel a siege? What kind of supplies do they have?

What kind of payloads are available outside the city? How well trained are the besiegers and how many/what kind of catapults do they have? What kind of defense do the besiegers have against fire arrows and oil used against the siege towers and the people in them?

. . .

How Stuff Works (http://science.howstuffworks.com/transport/engines-equipment/question127.htm)

Physics of various types of Catapults (http://www.real-world-physics-problems.com/catapult-physics.html).

Book from NOVA: Medieval Siege (http://www.real-world-physics-problems.com/catapult-physics.html)

Medieval Siege Weapons (http://www.amazon.com/gp/product/1841762350)

I guess the answer to those questions is: Whatever is needed for the events to play out. My style isn't to go into much detail. I mostly stay in the characters' heads.





Maybe you should consider having your army come up with some kind of super weapon. Because if theyre just using convention tactics, there arent too many ways to crack a fortified town that quickly.

Well, they ARE being led by an evil sorcerer who can among other things rain fire from the sky . . . but he wants to capture the city intact and rule over it, so he has to hold back on his more instant win powers. The third act is about him going to greater extremes and causing more destruction as his patience runs out.

ULTRAGOTHA
05-06-2014, 02:27 AM
I guess the answer to those questions is: Whatever is needed for the events to play out. My style isn't to go into much detail. I mostly stay in the characters' heads.

OK, then, what do you need for the events to play out? Do you want the besiegers to win or to go away?

If you want them to win, how long do you want it to take from settling in for the siege to taking the city? What shape do you want the city to be in when it's taken? Do you want the besiegers to hold off the reinforcements after they take the city? If so, with what result? Total rout?

benbenberi
05-06-2014, 02:37 AM
Well, they ARE being led by an evil sorcerer who can among other things rain fire from the sky . . . but he wants to capture the city intact and rule over it, so he has to hold back on his more instant win powers. The third act is about him going to greater extremes and causing more destruction as his patience runs out.

Sounds to me that by far your best bet for capturing the city intact in a hurry is to get someone on the inside to open up and let your army in the easy way. Bribery is often a winning strategy in affairs like this!

Williebee
05-06-2014, 02:45 AM
Can't add much to the very good info already offered. But, I can tell you that the trebuchet in my backyard can take out the streetlight just down the hill.

Turns out? Those things aren't cheap.

Rufus Coppertop
05-06-2014, 07:43 AM
walls were made of stone but held together with dung, mud and straw. Very susceptible to fire. just a few ideas
Where and when did nobles with access to masons who knew how to make decent mortar and build castles, walls, bridges and cathedrals that have lasted a thousand years or more, ever go to the expense of having stone quarried and hewn and carted to the site, foundations laid, plans drawn up and labourers paid, only to settle for highly expensive walls of stone that were completely useless because of flammable mortar?

Telergic
05-06-2014, 09:44 AM
Fire in various alchemical and ballistic forms has been available for siege weapons since the dawn of history. Manuals for concoctions of sulfur and naphtha and similar incendiaries long predate the discovery of saltpeter. Concrete has also been around since ancient times.

I too find it hard to believe in inflammable mortar as a defensive siege vulnerability.

efreysson
05-06-2014, 10:42 AM
OK, then, what do you need for the events to play out? Do you want the besiegers to win or to go away?

If you want them to win, how long do you want it to take from settling in for the siege to taking the city? What shape do you want the city to be in when it's taken? Do you want the besiegers to hold off the reinforcements after they take the city? If so, with what result? Total rout?

The rough scripts outline in my head demands at least four or five days after the initial assault. I want the city to emerge with some damage but nothing catastrophic.

Eventually the attackers do breach and invade the city . . . and then (of course) the defenders get reinforcements. The attackers get caught between two armies and squashed.

JoeHill
05-06-2014, 07:39 PM
The rough scripts outline in my head demands at least four or five days after the initial assault. I want the city to emerge with some damage but nothing catastrophic.

Eventually the attackers do breach and invade the city . . . and then (of course) the defenders get reinforcements. The attackers get caught between two armies and squashed.

Ah...Something like Pavia(yeah yeah, I know it's not medieval).

Bolero
05-11-2014, 08:47 PM
How about an outer area - a less heavily defended new suburb outside the walls where a new wall is still under construction? They could get in that and then be trapped there.

Or if there has been peace for a while, then sometimes towns extended beyond their walls and you'd have timber frame buildings close to the wall to set on fire, or a building that you could use to stand your ladders on and get a head start - and your troops could gather in the building and be mostly protected from defensive arrows (though not dropped boulders) as they queue to climb the ladder.

WeaselFire
05-12-2014, 02:19 AM
The rough scripts outline in my head demands at least four or five days after the initial assault. I want the city to emerge with some damage but nothing catastrophic.

Eventually the attackers do breach and invade the city . . . and then (of course) the defenders get reinforcements. The attackers get caught between two armies and squashed.
Given this, a siege and catapults are likely out. Breaching a castle in a short amount of time (not in months) requires a weakness. Until gunpowder came into common use, castles rarely fell. The garrison was starved out in most cases, but the normal battle was the invading army rolled up to the castle wals an set up camp. Then they beat on the walls and doors hoping they could get in. When fall rolled around, the invading army went home to harvest and left the besieged castle alone.

Find the weakness. An unknown underground passage. A risky climb up the back side cliff. Capturing the crown princess wandering outside and ransoming her. Building a giant wooden horse as an offering...

It's your story, and it's not historical. Invent something believable in your world.

Jeff