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Siege logistics

Discussion in 'Writing Discussions' started by skip.knox, Apr 5, 2015.

  1. skip.knox

    skip.knox toujours gai, archie Moderator

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    How many people does it take to attack Constantinople?

    OK, the real question is how many goblins, but my goblins probably aren't your goblins, so let's just stick with humans for the moment. The Constantinople in question is late 4thc, so it's the Contantinian walls, not the much more impressive Theodosian walls. Even so, the walls stretched about three miles. It's not really a siege, it's a full-on assault.

    Here's how I did the math.

    Three miles equals 15840 feet. Call it 16000 to simplify the arithmetic. Any one human is going to need about four feet horizontally--two feet and change for his body, plus a bit of room on either side. That comes to around 4000 humans to stand at the base of the wall, not quite shoulder-to-shoulder.

    I have to say, that's not nearly as many people as I would have guessed. Now, an assault is going to need more than that, but even if you figure five guys deep, that's still only about 20,000 to attack the city. That's well within the range of late antique armies. There would need to be the logistics folks and so on, of course, but we're still talking well under 50,000 for a total army.

    That's just for general conversation. The real purpose of the exercise was to find a way for my MC to attack the commanding general (okay, goblin king) without being spotted. I had figured everyone was off attacking the walls. Not literally everyone, you understand, but leaving behind just the general staff, as it were. But with 200,000 bad guys, I find myself left with a *huge* surplus wandering around. My MC is sure to be found.

    I have some ways around all this. I offer up this little exercise as a demonstration of how pure logistics--geography, siegecraft, whatever--can have a significant impact on plotting.
     
  2. ThinkerX

    ThinkerX Myth Weaver

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    Hmmm...

    I seem to recollect a 10 to 1 ratio being the desired number for over running a fortified position. If the position is especially well fortified...maybe 20 to 1.

    I remember reading a short piece you posted a while back about goblins sacking and eating the populace of another city. Now, however, you seem to be describing them as organized - the Goblin King reference. (I have Goblin Kings on my world as well - smart, long lived, and very talented with magic, but that's beside the point.)

    So...are your goblins semi-civilized? Do they manufacture weapons, cook pots, or cloth? Do they require shelter from the elements? Do they have healers, or do they devour their wounded? Because the answers to these questions changes the answers to yours.
     
    wordwalker likes this.
  3. buyjupiter

    buyjupiter Maester

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    Is a disguise out of the question? What I mean is, would your sneaky character be so observably different from the defending force that there is no disguise that would possibly work? Like an elf trying to sneak around as a dwarf, but without glamour. (No, no I'm just a very tall dwarf...probably ain't gonna work in that circumstance.)

    And if magical disguise is a thing in your world, that might get you around all sorts of things. (Sorry, just finished watching the Hobbit...and a magic ring of invisibility is quite useful, if you're needing to sneak around.)

    No city is impenetrable. There are little chinks and cracks in the walls beyond just walking through the gate. Aqueducts and storm drains, for one. The possibility of planting your guy on the inside of the city, before attacking it, for two.

    It all depends on how expected vs unexpected the attack is (on either side). If your attacking force woke up one morning and went, oh it's Tuesday, I feel like attacking the city; but the city that's being attacked doesn't have enough time to raise up a good defending force...you're gonna get some different results vs a long war that has had many battles and the army is slowly progressing towards the city.

    If the siege goes on any length of time, all the attackers have to do is sit and wait and someone usually ends up opening the gate...at least historically speaking.
     
  4. psychotick

    psychotick Auror

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    Hi,

    Sieges don't work on numbers like that. The ten to one ration mentioned has nothing to do with sieges. It has to do with overrunning fortified positions. For a siege to be successful the siege army needs the numbers to do three things. First to contain the forces within the city from being able to ride out. That would probably only require a little better than a one to one ratio. Second enough forces to stop supplies from entering the city. Essentially sieges are about starving people out. And last sufficient forces to carry out any additional actions such as use war machines to drop flaming missiles over the walls and burn the city out, and also guard their rear in case of a surprise attack by the defender's allies.

    In my view a two to one ration of attackers to defenders should be enough. But remember sieges can traditionally last for years and tactics and strategy are everything.

    Now your OP suggests your MC is inside the city. His main tactics should be building up fortifications and potentially building ramparts and war machines, if necessary by cannibalising the city. These will give him a range advantage over his besieging forces. Tunnelling so the city can mount surprise attacks on the besieging forces - usually at night and also get communications and supplies in and out of the city. Forming alliances with other external forces. If he can do it and bring an ally to attack the goblins from behind while at the same time his forces can ride out and attack from the front, the goblins will be caught. You can't defend front and rear at the same time.

    He also has the option of a bait and run tactic. Send out a party of riders to charge the goblins. Launch a lightning strike then tirn an race back to the safety of the walls. If they can do that successfully, the goblins will give chase. If everything works out perfectly the goblins will find themselves under the walls and in range of archers where they can be cut down.

    Your goblins on the other hand should be sapping the walls (undermining them by using engineers to dig underneath them again at night), building siege engines, and essentially starving the defending forces. They win if they can force the defenders out to meet them without the walls as a defence.

    Cheers, Greg.
     
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  5. wordwalker

    wordwalker Auror

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    Agree with Psychotick, with one small addition: the forces that keep the defenders bottled up also have to keep reinforcements from joining them. But really, a siege is about endurance-- each side trying to wear down and outlast the other, often by sheer starvation (on both sides, remember) and the threat that either could launch raids or shift to a full assault whenever they liked those odds better.

    For a true assault, it's not about surrounding the city-- at least, not after you've got enough troops spread out to catch raiding parties and messengers slipping out. You only need to break through in one point, if it's a big enough hole to keep push through with the defenders trying to stop you, so you concentrate forces on a gate. And/or, you hit several gates or build siege towers so the defender has to spread himself thin.

    I sometimes think of fortress defenses as giant bullseyes: attacking forces can just file through them, but only by exposing themselves to all the damage the defenders can throw at them, and better walls just mean the attackers have to walk more slowly and take more pounding. If they can survive the gauntlet and fight through the defenders too, they win. (In contrast, consider an empty castle: walls are all there, but with nobody on them it can be taken by one man with a grapnel.)
     
  6. skip.knox

    skip.knox toujours gai, archie Moderator

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    Thanks for the excellent comments. I've Evernoted them for future reference because I'll have other sieges in other stories.

    This one's a little different, for two reasons. One, exact details are still in flux. I do my worldbuilding as a dialectic between the story and the world. Psychotik noted my MC was inside the City, but the story has changed and now he's outside. Exactly what the goblins are, exactly their level of sophistication I keep shifting, trying to find the sweet spot for them. They are *mostly* animal with many characteristics of swarming species, but there are some special ones. Not sure if they are genetically different or what (working on a theory about magical genetics), but the Gniva (the "king") has a sense of strategy individual goblins lack.

    My goblins have no clue how to attack a walled city other than to claw at it or try to jump over. That's why it's not really a siege, it's a sustained assault.

    Yes, buyjupiter, invisibility is indeed useful. He's got it, though it's awkward and a bit unreliable. It will get him close. But that's one reason why I was doing the calculus. If the Gniva is surrounded by 20,000 swarming goblins, invisibility won't matter--you'd be found by touch. So I had to come to some general understanding of the physical distribution of the goblin Horde across the hills outside Constantinople, as well as get a sense of how long it would be before they would be able to come over (or through) the walls even without siege equipment. I mean, eventually enough bodies would pile up at the foot of the wall, they could vault over. A swarming species would behave that way. At the same time, though, I had to figure out how long it would take them to eat their way through the countryside and begin to starve, and so move on.

    As I said in the OP, the details are mainly my own challenge. What I found of more general interest was how logistics set parameters to the actual story telling, and how I could adjust story telling elements to take account of those parameters.
     
  7. ThinkerX

    ThinkerX Myth Weaver

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    Skip, in that case, the most likely strategy by far for your goblin king to employ will be to pick one section of the wall that seems a bit more vulnerable than the rest and launch repeated attacks on that position with the vast majority of his troops. Depending on how intelligent he is, after a few days or so it might dawn on him that the defending troops are concentrating on that position, leaving other parts of the wall undermanned. At that point, he launches a major feint at that position, and when the defenders are committed, throws everything he has left at a more lightly defended portion of the wall. Even so, given that he's got a mob, and not a disciplined force, he's going to be loosing AT LEAST ten of his own for every defender slain.

    Despite their animalistic nature, would improvised scaling ladders and battering rams be beyond the goblins abilities/intellect? Weak spot of the wall being one with a door, or a bit lower than the rest. (Maybe use newly felled, untrimmed trees for ladders and rams?)
     
    Last edited: Apr 5, 2015
  8. 2WayParadox

    2WayParadox Sage

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    When I do research on any topic for a fantasy world, I like to read ancient sources from all kinds of cultures. If you can find them of course. I haven't read the one I'm linking in this comment, but I certainly plan to when I get to a story that deal with siegecraft.

    https://www.goodreads.com/book/show/1945223.Aineias_the_Tactician

    The author, in the mid-fourth century BC, of "How to Survive Under Siege", Aineias the Tactician is not only the earliest but also the most historically interesting of the ancient military writers. The last 20 years have witnessed a growing appreciation of his importance as a social commentator on the nature of life and the strategic and psychological preoccupations in a typical Greek city-state at a time dominated by two extraordinary and untypical ones, Athens and Sparta. In Aineias we see what conditions were like in a "polis" obliged to play the passive role in the history of its age: not laying siege but suffering it. His recommendations on this clearly derive from his own accumulated experience, but he also draws copious illustrative material from other writers including Herodotus and Thucydides. The author provides a comprehensive introduction and a full historical commentary.
     
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  9. psychotick

    psychotick Auror

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    Hi,

    Your last post changes things. First if the goblins are mounting a constant and sustained assault on the city, then it's not really a siege at all. They are literally trying to overrun a fortified position. At that point the ten to one and twenty to one ratios come back into play. Except that if the goblins really aren't intelligent - and I understand that this is in flux as you say - those ratios go way up. You may end up needing over a hundred goblins for every defender. Simply put every defender simply sits on the ramparts with a bow in his hands, and simply rains down death on them as they come.

    Limiting factors for the defenders would be how many arrows they have etc and whether the goblins have the brains to stay out of range. As for simply over running overrunning a wall by the sheer press of bodies and walking up the pile of corpses, this is really tricky. But the numbers are astronomical. Assume your wall is thirty feet and that a goblin is roughly human sized. Also assume that they fall sideways when they die and that in order to create a ramp to the top of the wall they need the slope to be roughly thirty degrees.

    Now your calculations become simple. The tan of thirty degrees is about 1.7 which means that if the wall is thirty feet tall the adjacent needs to be about fifty one feet long. Assume for simplicity that each goblin lying side on is one foot wide and one foot thick. The area of the triangle is 761 square feet or 761 goblins. And assuming that each goblin is six feet tall, then that means that every six feet of wall width requires 761 dead goblins pushed up against it in a heap, in order for the survivors to run over them and clamber over the wall. now assume the goblins attack as a mob, spread out over only a section of wall six hundred feet wide not the full three miles. That comes to 76000 bodies before the survivors can attack the defenders.

    Of course this is just trig and depends on so many assumptions that its little more than blind guess work. But it gives you at least the right football field to play with.

    As to how your MC gets out, I'd go with tunnels.

    Cheers, Greg.
     
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  10. stephenspower

    stephenspower Inkling

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    Why are the goblins attacking the city?

    How do they fight unentrenched positions?

    What level of tech and engineering do the goblins have?

    What is their natural habitat? If they're cthonic, tunneling under the walls not only makes sense, they might have the skill to start miles away so that the enemy can't even see them coming

    Personally, I'd catapult them over the walls with little parachutes to let them rampage through the city. No one would expect that.
     
  11. skip.knox

    skip.knox toujours gai, archie Moderator

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    Thanks in words to psychotick for doing some math for me. I've got about 200,000 goblins to work with, so the ramp of bodies is numerically feasible. Plus, they can jump. They're better at jumping far than high, but ought to be able to clear ten feet or so, which lowers the ramp somewhat. I'm pretty sure the Constantinian walls were around 30 feet high, though height probably varied (it certainly did with the Theodosian walls). FYI, I have that many goblins because my historical reference is the invasion of the Goths in the 370s. One nice thing about playing with alternate history is I'm free to accept exaggerated accounts!

    Thanks to 2WayParadox for the Aineias reference. It's now on my ToRead list. It may give me some tips for narrating what's going on inside the city. I've read Runciman's Fall of Constantinople, which provided a couple of plot moments.

    @stephenspower: think locusts. Combine with the hunting instincts of wolves or other pack animals, or maybe certain species of ants. That's the general region I'm operating in. So, no tech. I do have a amusing/frightening scene in which the defenders look out and see goblins wearing--badly--various bits of Roman armor they took away from the battle at Hadrianopolis. But the goblins have no clue about using bows or swords, so no parachutes either. :)
     
  12. spectre

    spectre Sage

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    Other considerations beyond a city siege might include forces belying the countryside. There are a number of waterways that can be utilized to which in stories a lot of Goblins have an aversion. You would do best to rule out going through the gates because of the assault, but depending on where your Goblin King and MC are there are options. You can utilize the Theodosian Walls (man left behind or separated from the rest by the siege --behind enemy lines). Those are probably the two obvious answers without a war plan given Goblin traits. Maybe there are some landmarks near the walls?

    Constantinople - Wikipedia, the free encyclopedia
     
    Last edited: Apr 6, 2015
  13. buyjupiter

    buyjupiter Maester

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    OMG, that is brilliant. *scribbles down notes* I don't know that I'd use that in particular, but the idea in general, yes.
     
  14. wordwalker

    wordwalker Auror

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    You know, that might actually work. If something's smaller than human, the square-cube law says it's a lot lighter, so you might not need modern industrial materials for a big enough parachute that can take the strain...:rolleyes:
     

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