Castle Moat Full of Zombies

Question

It's the modern day, somewhere in Europe. Guns are generally difficult get a hold of, and ammunition is not all that plentiful for the average citizen. The cities are death traps, and hordes of thousands, if not tens of thousands of zombies are sweeping the land, looking for their next meal.

Ion just so happens to live close by a 1400's medieval mountain fortress. Although you'd think this would be the first place people would seek shelter in a zombie apocalypse, let's assume that the zombie virus struck terribly quickly, and violently, and only a couple of hundred individuals made it within its walls.

Now, Ion is a practical guy, and he realizes that he's got everything he needs on hand to survive for a long, long time:

• The fortress was a tourist attraction, but also kept functional as a military police barracks. Sadly, the vast majority of their equipment (guns, riot gear, ammo, etc.) is gone, but the place is set up to support a few hundred people living there (beds, mess hall, fridges, emergency generators, heating, washrooms, etc.).

• There's an armory of medieval weapons on display for the public, and although old, most of the blades, and pole weapons are serviceable. Most of the medieval armor pieces on display are too small, worn, etc. to be used, but a few individuals might be able to armor up for some CQB zombie smashing fun.

We will be ignoring how these people are going to be procuring food, more weapons, etc. Ion has other things on his mind. The moat, though huge, is empty, and he is really worried about all those zombies roaming the land. Eventually they are going to make their way up to the fortress, and although the gates/walls will hold, what happens when the moat fills up?

Note: The moat is dry; there is no source of water to fill it up on demand (only a massive rain/snow melt might do so, and only temporarily).

Not only are the dead bodies going to cause diseases to break out, but the zombies might literally be able to climb over the walls on a ramp made of their brethren's battered remains.

And so, given that:

• There are no construction type vehicles available to dig massive graves, or otherwise empty the moat
• The survivors have some fuel, but not a lot of it (plus, they will need it for the generators)

my question is:

• How might the survivors keep the moat from filling up with dead/undead on a day to day basis (say 10-30 new zombies fall in)?

• How might they deal with the aftermath of a massive zombie wave which ends up leaving thousands of dead/stuck zombies behind in the moat?

Answer 1

If it's a Dry Moat - Burn 'Em

Emergency generators mean fuel, and fuel is flammable. At regular intervals (or just as needed), the people within the castle walls sling home-made molotov cocktails into the moat. Since the zombies do not stop, drop and roll they spread the fire to others in the trench, and eventually incinerate. It may take a few fires before a corpse is fully incinerated, but eventually it is.

At a point you may have an issue with the trench filling with ash and bones, but the basic strategy of using fire will allow considerably more zombies into the area before that problem comes up. Hopefully the survivors can find some shovels (or invert helmets) to clear out the mess on occasion. They could even use the debris to start building up another, further out wall that would help discourage zombies from wandering into the castle moat.

This plan has the additional upside of helping deal with disease.

Edit 1: As a bonus, this plan does not typically require any combative engagement with the Z's. The fire is ITSELF the means used to "kill" the zombies. Greater concentrations of zombies are more likely to start a mass conflagration and hotter fires, so let the hordes come! Guns/hand-to-hand combat is reserved for wet/rainy days.

If it's a Wet Moat - Much More Complicated

The best thing would be to do whatever is possible to dig some kind of a basic water release, which would then let you get on with Scenario 1.

Otherwise, you can use the trench to slow zombies down and destroy their brains at your leisure. Using pole weapons, lift floating corpses out of the moat regularly and bring them to a storage area inside where they can be incinerated.

Answer 2

The zombies will NEVER get over the walls.

Why?

Physics. Zombies are basically human bodies that are still moving despite being in varying stages of decomposition. Human bodies are mostly water. We do have some skeletal structure, and some of it is very strong, but for the most part, we are bags of water. Now, what happens when you stack up enough people to make a pile of bodies as tall as a CASTLE WALL?

Pop goes the water balloons. Humans (who are living and hence, WAY more structurally intact than an average zombie) are crushed like grapes by the pressure of that many bodies on top. So what happens with rotting zombies? Probably, they would liquefy at the bottom and actually FLOW AROUND THE CASTLE like a mud flow. Gross, but they will never get over the walls.

What about the moat? It will stink for sure, but even if you don't find a way to light them on fire, the sheer tangle of zombie bones, body parts, limbs, crushed zombies, etc, will become a tangle of barbed wire for other zombies as they try to cross toward your castle. Like velcro, zombies will get stuck in there. The ones on the bottom will liquefy and rot away and the ones on the top will continue to trap more. Basically, even if you do nothing whatsoever, medieval fortifications will totally defeat a zombie apocalypse.

Answer 3

Start a vulture farm.

I'm not sure how your zombie virus affects vultures, but vultures are biologically developed to eat rotting flesh, and would probably do a slower (but better and safer) job than a pig farm would. Simply let them out to eat every day and they'll likely go straight for the dead zed at the bottom of your moat.

How your survivors get their hands on and train the vultures is a different problem.

Answer 4

A constantly-burning crematorium

One of the towers might be re-purposed for this. During lulls, well-armed/well-organized parties would go into the moat and fetch another round of zombie fuel - that is, they would collect zombie bodies and bring them back into the castle and burn them in their zombie furnace. Massive zombie waves simply take more time. This constant source of heat could possibly be put to good use, but would be a by-product of a virtually never-ending zombie disposal effort. This solution assumes that they don't have a large supply of other fuel and are unwilling/unable to forage for more.

Edit: The 'how' is simple and is the only way they have: By hand.

Edit #2: More on the "tower" idea. The tower would act as a smoke-stack of sorts. Smoke stacks not only direct noxious smoke and fumes away from the burning, they are instrumental in creating draft, from the bottom where the fire is to the top. This helps supply the fire with oxygen better than it could draw by the burning process alone. They would have to somehow build a raised surface with holes as a burn platform. The bottom of the tower would then be the ash-pit. The accumulated ash could be cleaned out without the need of putting the fire out - round the clock zombie disposal.

Another reason to use a tower is the sheer size of the fire you would need in order to fuel it with zombies. Bodies will burn if the fire is hot enough and big enough. The massive wave of zombies would be a blessing of sorts. They would need an ample supply of dead bodies to feed the fire.

Still another reason to use a tower is that it is inside the safe perimeter of the castle. And the fire is hidden and won't unnecessarily attract more zombies.

Answer 5

You could try some medieval tech to go with your lodging...

I'm thinking you could use an oversized trebuchet, or perhaps a few trebuchets to launch zombies a fairly long way away.

With this trebuchet you could launch 1500lbs a little over 100ft, so that would be say ten 150lb zombies out of the moat and likely pretty well smashed upon landing. Or one zombie much further...

1. Build your trebuchet
2. Raise your counterweight
3. Lasso a few zombies in the moat
4. Lob them out
5. Rinse and repeat

Here's a little inspiration, if you have doubts about throwing heavy objects long distances

Also...

It's a trebuchet... so you have the option of throwing all sorts of fun things at approaching zombies. Think of it this way, instead of 2 birds with one stone, you get 10 zombies with one throw, plus however many zombies you manage to hit.

Answer 6

It must be acknowledged that the moat cannot be cleared quickly. The question of "how to empty such a moat" is really difficult to answer, because it takes manpower, involves exposure to diseases, and more.

You must turn to solutions that prevent the zombies from reaching the moat in the first place.

Remove their incentives

Depending on how your zombies work, they may require certain stimuli to detect prey - such as sound and visible light. Make quiet mandatory, enforce curfews, and block all possible lines of sight. The risk of a pileup is significantly reduced if they can't tell you're there.

Far-range barriers

Working in tandem with my first suggestion, create a system of walls, trenches, and / or other barriers a good distance away from the actual castle - far enough to prevent any zombies from getting close enough to know you're there. They do not need to be strong, because they will rarely, if ever be besieged. As long as they can't accidentally be breached, but they're strong enough to keep things out that bump into them, you're good to go.

Bar the roads

The road is your best friend, and your worst enemy. It allows supply runs, but it's also the easiest path for any invader. Establish checkpoints / gates along the road - they don't have to be manned, as long as they can be unlocked or surpassed by vehicles - that would prevent massive swarms.

Moats further away

If you have sufficient manpower (and time), consider war-style moats. These should be outside the castle walls, and outside of any agricultural land, but inside the far-range barrier; they will catch many invaders on the way in, but less invaders each, and there won't be a ton of pressure to clear them out.

Upturn the castle walls

Now, in the unlikely event that zombies (a) reach the main moat and (b) pile up to a climbable height, your only concern will be disease. Having a wooden ledge or overhang above the walls will prevent direct climbing - or at least postpone it for a very long time.

Answer 7

Institute pole duty among the inhabitants. In shifts, the people on pole duty walk around on the battlements with long poles (eight feet is long enough). They use the poles to push back any zombie who is on a pile high enough to reach the battlements. That zombie falls and gets even more damaged.

Soon there aren't enough intact zombies to form a pile that can reach the battlements.

Answer 8

Burn them when the moat fills.

Send teams to get wood, wood, and more wood. Take every square inch you have to cure the wood so it burns better, rotate the older wood out. Since the moat will take time to fill, this should buy you time to collect wood.

When the moat begins to get to a point where it's getting dangerous, drop all the wood and some fuel to get it started, keep dropping wood from the walls to keep the fire burning until there is nothing but ash left.

Eventually, your stockpiles of wood will become massive enough, and dry enough that you won't need fuel to get the fires started, Also, tar and soot will build up as well, and make the fires easier to start and maintain. Pine burns quickly, and is good for starting fires, Oak burns hot, as does cedar.

The difficulty would be in the logistics of cutting wood and retrieving it. If raiding parties could be sent to villages, houses and furniture could be cannibalized.

Answer 9

There IS NO moat

Proper mountain castle doesn't need no puny moat. No moat can beat tens of meters vertical rock walls on one side and absurdly steep climbs on the other - if they climb up to the wall, give them a push and watch zombie dominoes. This incidentally makes it a terrible place for military police garrison - no easy road means you can't get out to police anyone easily, but that's entirely different problem (solvable if you replace MP with border guards and place your castle near some border - rough terrain needs to be guarded and patrolled all the same, and castle near border would make a good place for active duty border guard barracks, in fact, due to difficulty in using vehicles, you probably need more people than on flat terrain).

Answer 10

This would require some engineering and planning, but what if -just what if- this mote wasn't used to keep the zombies out? What if it was used like a trap? A temporary holding cell?

There are two huge concerns that could be addressed here; disease and energy. Burning the zombie corpses in a controlled manner as a fuel alternative could have many great benefits. In the Winter, the corpses could help to provide heat throughout the castle, much like a boiler / furnace. In the Summer, there may some steam capabilities (although an abundant water supply may be a different story).

Frequent burning as an alternative fuel source may not solve the problem entirely, but may alleviate it. The mote could be altered to funnel traffic into 'kill zones', where trained teams using melee weapons with extended range can kill them and recover the corpse safely (perhaps using some sort of hoist mechanism).

On another note, I think that attempting to conduct controlled burns in the mote could have potential for devastating consequences. An out of control fire could find it's way inside the castle walls, then you have a real problem. You also probably don't want the bodies to continue decomposing into the soil so close to the castle. Eventually that will contaminate the soil insides the castle walls, and thus affect agricultural efforts.

Answer 11

Put in a ramp so that zombies that fall in can walk back out. While a moat can be a good deterrent against human adversaries, it is a much less effective barrier against zombies. A sufficient number of zombies can easily fill up a moat given enough time. Even un-motivated zombies can fall in accidentally. If the goal is to prevent this from happening, then the easiest way to do this is to give the zombie a way to leave on their own. Depending on the moat design, a simple wooden ramp should provide an easy exit. While zombies are not particularly durable, the don't feel the pain of injuries and most that fall in should still be ambulatory enough to continue walking or crawling. If there is no stimulation drawing them to the castle, then they should eventually discover the ramp and wander away following some other sound or smell. If you are lucky the geography around the castle might provide a convenient entry and exit for the zombies. For example, if zombies tend to always approach from one direction and fall in, you might put the ramp on the far side where they might walk up the ramp and tumble down a hill, unlikely to walk back up.

In addition, if you would like to speed the exit of the zombies you might provide incentives for them to keep moving and exit on their own. This of course may depend on the type and motivations of your zombies. For example, if the zombies in your land are attracted to sounds it should be a simple matter to place something that produces noise near the top of the ramp like a bell that would draw zombies in that direction. You could further rig it so that when a zombie walks on the ramp it rings the bell drawing the zombie forward and attracting more zombies from the moat towards the ramp. If the bell is not too loud you can avoid attracting zombies that are not already in the moat from further falling in.

Some zombies that fall in may become too damaged to leave on their own, but this number should be greatly reduced. Zombies that become damaged and stuck in the moat would likely be trampled and ground into the earth by the "healthy" zombies but since this number would be much smaller it would likely never fill the moat.

If a zombie hoard arrived, the trick is to keep them moving. When members of the hoard fall into the moat they should follow a route around the moat until they reach the ramp, and then climb the ramp and continue right on out the other side, or hopefully tumble down your hill and keep walking somewhere else.

Answer 12

I find that if you create a diversion somewhere else, such as a loud windmill, the zombies will be attracted to this and not your castle (The Walking Dead). Of course this will eventually need maintenance but a big ol' fire should sort them out. This will alleviate some of the fresh zombies from piling up and give time for them to liquify (as some other answers suggest). Also, moats are usually lower than the walls of the castle and the overspill of goop will just fall out of the moat.

In regard to the pests, animals are terrified of the walking dead (brooks) so they should steer clear. If not, general hygiene will be your best friend. Have high up mess halls and kitchens and keep them clean. Wash clothes, keep your socks dry, make antibiotics a run priority under food and don't do anything stupid, like armour up and try and defeat the horde. Most castles have a well which should be tapped into the groundwater system and, if deep enough with enough rainfall, shouldn't be affected by the zombie goop.

Answer 13

Re purpose the armor and chain mail to make bite proof suits and go out and render the zombies down for fat fuel! the danger and gross factor would make it a good punishment for the slackers in your little community.

Ok, I'm not really sure how that would work, but lard burns and that kind of fuel could be used to start some good conflagrations in your moat to occasionally clear it. The Z-lard could also power boilers for heat and maybe power generation without using up precious supplies of Gas or Diesel

Also, can you imagine the reputation you could gain if you could say that your castle was powered by the fat of the damned :-)

Of course all of this depends on the transmission vector of the Zombie bacteria or virus or whatever.

For something more practical, depending on what minerals or other materials you have available, you may want to sprinkle a corrosive into the moat on a regular basis to speed up the decomposition of the zombies in there. If it's sufficiently caustic, it may also reduce vermin populations and the problems that go with them. Lye is very caustic and can be produced from hardwood ash. Lye is also used to help produce biofulels for other purposes. Back to powering your castle from the fat of the damned maybe?

Answer 14

The moat could be part of a river system, and have a strong current. Imagine a castle built on a small rocky outcrop in the middle of a fast flowing river. With appropriate stonework the river could be channeled around each side of the castle and have a strong and deep current, enough to sweep attackers bodies away.

Answer 15

World War Z (the book) covered this pretty well. The Queen refused to leave Windsor Castle, because she would not abandon her country. There are suggestions that other castles around Britain were also used as strongholds. As a result, the Brits became experts with the medieval weaponry which was hung all round these castles for ornamentation, and mostly switched away from using firearms.

Brooks gave some serious thought to how you fight zombies and how soldiers would be trained. The key realisation was "Zack ain't in no hurry, why are you?" So long as you can see them coming, you just need to pace yourself and keep knocking them off. Zombies climbing up a ramp of other zombies are never going to get to you quickly.

Answer 16

Food processing

The consultant you called in from Iowa made quick work of it. My apologies for any mistakes in the recounting, but he said that this here is a John Deere 9870 STS combine harvester with a 625D Draper head that had been on the premises of his dealership. The owner passed away recently, but it seems right to borrow it for a while. The engine trouble it was brought in for hasn't been fixed, waiting for parts on back order, but he reckons it doesn't matter so much as normally because this is a crop that will walk to you. Farmer's dream, really. He'll customize the reel and header auger for your very high density crop requirements and to ensure that it fits nicely in your particular moat. Zombies can't climb over the bars so long as it is running, and they can't go under without having a meeting with the cutter bar. Just make sure you build a decent moat wall/partition behind this machine so you don't have to recruit more operators; there's a labor shortage at the moment.

Processing of the zombies occurs roughly as follows:

Note the presence of threshing equipment to deal with any bones and such your zombies might possess. Why, there was this case of a boy who fell asleep while trespassing in a field last year (chuckles)... the machine can handle it, though you want to keep a local consultant on hand to optimize processing for your application. (He seems a bit eager for a place behind the walls, I think)

Note the tube at the right end which can be emptied into a truck or even a conveyor system if desired. With appropriate processing to inactivate pathogens, there is very good protein in zombies. It is not a consumer meat, but it can be used like downer cows - I mean, like they used to - to make animal byproducts for animal feed, cleaning products, and perhaps other purposes. As lord of the keep this decision making will be up to you, so don't let opportunity pass you by!

Answer 17

Morning stars + Fire:

As has been pointed out, bodies don't burn very well due to the high water content. The typical human body does not have enough energy content to vaporize the water the typical human body contains, even with perfect efficiency (which certainly isn't going to happen) the fire goes out.

But what if we kill the zombies first? There's a ton of zombies in the moat, send a few people out onto the wall armed with morning stars with very long chains. You kill a zombie by destroying it's brain--and what's conveniently on top of a zombie?? Whack away at the zombies until you've killed a whole bunch of them. Leave them, let the corpses desiccate over time.

Now we have a moat with a bunch of actual fuel in it, when the moat has filled back up with zombies toss a molotov. All the previous kills burn, disposing of the bodies and killing the remaining zombies. Every time the moat fills up you throw another molotov--note that the fuel consumption here is very low as the molotovs are only being used to get the fire going, they aren't the fuel.

You can continue this cycle until the bones pile up too high.