Sunday 2 July 2017

Tunnels and tunnel fighting

This week, I had the opportunity to walk (and, at some points, crawl) through the medieval tunnels under Exeter.

Me in a tunnel, as photographed by the person behind me.

The tunnels were dug in the 14th century, so that plumbers could access and repair the lead pipes which carried water to Exeter cathedral without having to dig up the road every time they needed to patch a leak. Visiting them thus gave me an enlightening insight into what medieval Europeans considered to be an adequate amount of space for people to move around in underground.

It turns out the answer is 'not very much'.

In those parts of the tunnels which weren't expanded during later centuries, they averaged about five feet high and two to three feet wide. In a few places they sank to about three feet by three feet - crawling room only. If you'd had to fight down there, there's no way you could have used axes or crossbows, let alone longbows or two-handed swords; knives and maybe shortswords would have been much more appropriate. You couldn't have used big shields or bulky armour, although a small shield would have been incredibly valuable, as there would have been no room for your enemy to strike around it. You couldn't have run, or even walked quickly - there were too many places where you'd have to edge your way sideways or crawl instead. And everyone would have been hitting their heads on the ceilings every few seconds.

It made me think about those standard low-level D&D enemies, goblins and kobolds and giant rats, and how terrifying it would be to have to fight them in an environment like that. How they could move quickly and easily through spaces where adult humans could only inch back and forth. How vulnerable you'd be while edging through a narrow space, and how easy it would be for something small and vicious to run up and slice through your tendons while you were basically incapable of defending yourself. I'd much rather have fought an orc than a goblin in those tunnels. Orcs would have had the same problems we did. Goblins would be stabby death on legs.

Tunnel passage
'Just go down there and kill ten giant rats, he said...'

The standard Gygaxian 10' square dungeon corridor isn't historically realistic - in fact, my experience this week suggests it's about eight times as wide as real medieval tunnels - but it endures partly for this precise reason: it gives the 6' 8" half-orc with a greataxe enough space to fight side-by-side with the 4' halfling with a dagger. You'd never want to make 5' x 2' the standard size of a dungeon passageway, partly because it would enormously disadvantage anyone who wanted to play a big (or even normal-size) character with a big (or even normal-size) weapon, and partly because it would turn the game into a tedious exercise in dealing with the same set of practical problems over and over again. But once in a while, sending a party into a warren of tunnels like the ones under Exeter could make for a very tactically interesting scenario, especially if it pitted them against under-sized enemies like kobolds. It creates a whole bunch of asymmetries: you're strong but slow, they're fast but weak. You want the fighting to happen where the tunnels are widest; they want it to happen where the tunnels are narrowest. If one of them gets injured or killed, you can probably step over it; if one of you gets injured or killed, then that person will block the entire tunnel. Your most powerful weapons and armour are also the ones which are hardest to use effectively. 'Do I use a knife or a longsword?' becomes an actual choice for once.

(Zombies would be another good option: having to run away from a bunch of Romero-style shamblers in an environment like that would be a nightmare, especially as they, unlike you, won't care how often they whack their heads on the ceiling. And yes, sure, you can use fire: but then what about smoke inhalation? You need to breathe and they don't...)

Anyway. Medieval tunnels. Really fucking narrow. You might want to leave the battleaxe at home. 


  1. Do you remember the tunnel from labyrinthe?

    I suspect you undervalue big people in small tunnels - the most effective combination of armaments is almost certainly shield and spear, and at that point it's going to turn into a rather nasty shoving match, and for that size and strength would be vital, and not being able to stand up straight might not matter that much.

    1. Yes, I remember it... Chislehurst Caves was what I was mentally comparing the place to when I was down there. These passages were much narrower. I often had to turn slightly sideways to get down them, and I'm not exactly broad-shouldered.

      You may well be right about big people in small tunnels, but in a space that constrained I'm just not sure that you'd be able to leverage your size and strength effectively. And you could *hold* a spear, but could you really *wield* it? A human-sized enemy would have no way of approaching you without walking into the pointy end, but your mobility would be so constrained in the narrower areas that I suspect that something smaller and more agile could just move *around* it...

  2. Your photo isn't loading for me, sadly.

  3. Low tight tunnels now and again gives time for halflings, gnomes, and dwarves some time in the spotlight.

    1. Fucking gnomes, man. Always looking for a chance to show everyone else up.

  4. Thoughts on this video?

    Also the same channel has lots to say about D&D. Interesting watches for the most part.

  5. I feel that those tunnels were only adequate for their purpose. i.e. occasionally performing maintenance.
    If the tunnels were built for another purpose then they would be built to suit that purpose.

  6. First image isn't loading.
    If I try visiting the source, it asks me to log in.
    If I do that, I get an error page that just says "Gone
    Error 410"

  7. Have you read the Tunnels of Cu Chi? It's a really interesting book about the tunnel rats of the Vietnam war. It does a good job communicating the awfulness of fighting / living in crawlspace tunnel complexes, and how it was accomplished.

  8. 3'x3' sounds positively roomy, compared to access spaces in modern industrial plants. A 2'-diameter manhole is considered "unrestricted access", 1.5' is a typical minimum walkway width, and 3'-diameter pipes/tunnels/ducts/etc. are considered suitable for internal work like welding (with an air supply or forced ventilation, since gassing out workers is bad for business).

    Of course, it's funny how often the people who set those requirements don't actually work in those plants. You can usually tell because they have the shiniest safety gear. But I digress.

    Yeah, fighting shorties in their warrens should be a nightmare.