What does a 50 lb rock do to a stone building from 500' up?

[Umbran]

I would just ask myself, what would be more fun? or how can I make this interesting? Forget about whether it works or not, I mean, If the players want to do it, and its somewhat feasible, I say do it but add some excitement.

I agree. Except, there's precedent to be considered. How you handle this now will influence how they approach the next time they have to deal with a fortification. And how you deal with this now ought to be consistent with the world - if the players can do this, then so can anyone else of similar intelligence and resources, right? So, why isn't this a common tactic?

We're talking E6, right? I don't know the details of feat availability in E6, but... Fly is a 3rd level spell, and Craft Wand is available at 5th level, no? So, wands of Fly are possible at 6th level, and 50 pound rocks are well within the lift capacity of the spell. Ergo, if 50 lb rocks are enough, some warlord will spend a chunk of change on a couple of these wands, and bombardment will commence with a *hundred* flyers, each able to dump several rocks before the spell expires! Why doesn't this happen? If it does happen, have you worked that into your world-building?

My answer would be that it actually takes 100 - 200 pound rocks to really bust up a fortified stone building, which is getting to be outside the effective limit of the spell. The warlord now needs to send 3-4 people up per rock, and that starts getting prohibitive as a general tactic.

 

[Janx]

If I recollect correctly, rules-wise a falling object deals 1d6 / 200 lbs., +1d6/10 ft. fallen (max 20d6). So the rock would do 21d6 damage (ave 73 dam) to an object it hit. Structurally, a hewn stone wall (10'X10'X3') is going to be closest to your granite roof; with a hardness of 8 and up to 540 hp. Assuming the roof is probably only 6" thick (1/6 the hewn stone wall thickness), that'd give a section about 90 hp.

there's rules for that? I don't recall damage FROM a falling object in 3e.

If so, it seems like the problem solves itself. Follow the rules.

I would agree the bigger problem is as Umbran deduces, being consistent, and balanced as the PCs are going to pull this trick again, and again....

 

[Umbran]

The d20 SRD says:

Falling Objects

Just as characters take damage when they fall more than 10 feet, so too do they take damage when they are hit by falling objects.

Objects that fall upon characters deal damage based on their weight and the distance they have fallen.

For each 200 pounds of an object’s weight, the object deals 1d6 points of damage, provided it falls at least 10 feet. Distance also comes into play, adding an additional 1d6 points of damage for every 10-foot increment it falls beyond the first (to a maximum of 20d6 points of damage).

Objects smaller than 200 pounds also deal damage when dropped, but they must fall farther to deal the same damage. Use Table: Damage from Falling Objects to see how far an object of a given weight must drop to deal 1d6 points of damage.

200-101 lb. 20 ft.
100-51 lb. 30 ft.
50-31 lb. 40 ft.
30-11 lb. 50 ft.
10-6 lb. 60 ft.
5-1 lb. 70 ft.

For each additional increment an object falls, it deals an additional 1d6 points of damage.

Objects weighing less than 1 pound do not deal damage to those they land upon, no matter how far they have fallen.

Your typical lower-story city building wall is 1 foot thick, has AC 3, hardness 8, 90 hp - this includes its size. A typical small city wall is 5 feet thick, AC 3, hardness 8, and 450 hp per 10-foot section. And a typical heavy catapult does 6d6 damage.

You're talking about a technique that should do 20d6 with a single shot, by the rules. So, be careful with that.

But then, we should also talk about hitting the target - because while it is a building, it is also 500 feet away. This isn't a weapon that's actually *built* for use like this, so that's a -4 to hit as an improvised weapon. We don't have a range increment for "dropped stone". If we use a heavy catapult's range increment, that's another -4 to hit. If we use the light catapult's range increment, it is another -6. So, first estimate is a -8 to -10 to hit?

 

[Janx]

The d20 SRD says:
...snip...
But then, we should also talk about hitting the target - because while it is a building, it is also 500 feet away. This isn't a weapon that's actually *built* for use like this, so that's a -4 to hit as an improvised weapon. We don't have a range increment for "dropped stone". If we use a heavy catapult's range increment, that's another -4 to hit. If we use the light catapult's range increment, it is another -6. So, first estimate is a -8 to -10 to hit?

Thanks for the look-up. I learned something.

I can see why you'd want to make it harder, to reduce abuse. However, I'd question just how hard hovering directly over a target and dropping a rock really is. it has to be significantly easier than trying to throw it.

Lobbing a shot has a number of variables (wind, angles, energy, weight).
Dropping a rock is pretty much lining up the target beneath you (stability of platform) and wind. I'm not sure how much wind takes into play, but missing the center of the roof by 6 inches with a rock is still a hit, compared to missing the target's head with a bullet from 500 feet away.

If nothing else, size modifiers would be bonuses (larger target is a positive modifer) and thus reduce that -10 penalty.

I can see that being really high up would make it a harder shot. But if the target is big, you can hold position steady and easily look down to confirm you are over the target (basically, you can look over the ledge where you are dropping and easily see it is directly above because the target still appears to be larger than the ammo used).

maybe if the range increment was based on target size (small targets, from high up are harder to hit).

 

[Derren]

Make the test yourself. Put some small object on the floor and then drop a golf ball onto it. It is not that easy to always hit, especially as you would have a lot less stable platform to drop from, have to factor in wind and the stone moste likely won't be very aerodynamic.

 

[Gilladian]

There's some really neat, good advice in this thread! Thanks, y'all!!

I am definitely not wanting to set too big a precedent with being able to do massive damage raining from the sky, but I think I'll allow a few holes to be punched through the "dome" and wreck the defensive aura spells thusly.

Their "skysled" is actually a skywhale, of sorts; big and slow and can hover with a mental command from the "captain". The gondola below is where the PCs will be, and they'll be dropping the stones off the side of the deck. I'll definitely make them roll to hit! -8 seems to be about the right penalty, to me. And no Str or Dex bonuses! Maybe a Wis bonus instead, for figuring windage and such.

I like the idea of the various kinds of rock being more or less effective. they may have to work to find their stones!

 

[Umbran]

However, I'd question just how hard hovering directly over a target and dropping a rock really is. it has to be significantly easier than trying to throw it.

You're free to do so. But me, I kind of figure that holding a magical flying machine stationary in wind, when you probably haven't taken any proficiency or skill in it, isn't apt to be easy.

Meanwhile, keeping your trebuchet in one place, short of an earthquake, is pretty darned simple.

Lobbing a shot has a number of variables (wind, angles, energy, weight).

The only thing in there that you don't control is the wind. The rest (in normal physics, at least) is perfectly easy to calculate and make repeatable.

Dropping a rock is pretty much lining up the target beneath you (stability of platform) and wind. I'm not sure how much wind takes into play, but missing the center of the roof by 6 inches with a rock is still a hit, compared to missing the target's head with a bullet from 500 feet away.

Wind will affect the two situations equally, for the same distance traveled. Modulo the fact that winds tend to increase as you go up.

If nothing else, size modifiers would be bonuses (larger target is a positive modifer) and thus reduce that -10 penalty.

That's already taken into account in the wall's AC. Don't double-count it!

But if the target is big, you can hold position steady and easily look down to confirm you are over the target

I think easy station-keeping is a very big assumption that I'd question. It takes major skills in the real world. Why is it easy in the magical one?

 

[Wycen]

The Pathfinder game I play in had a similar possible situation just last Sunday. The difference I wanted to drop logs on the ceiling - well, actually "through" the ceiling. In a E6 game you cap your spells at 3rd level, is that right? So, you have access to Stone Shape. My idea was to open the ceiling and drop burning logs onto groups of defenders. I started a thread to get ideas too: http://paizo.com/threads/rzs2phy0?Besieging-a-fortress-when-you-dont-know-what#18

 

[tomBitonti]

Hey,

Why stop at 200 feet? Aside from accuracy problems, why not 1000', or 10000' feet?

A flier that can carry 10 people should be able to handle at least 2000 lbs, assuming that can be loaded.

Something I was wondering ... what difference would it make if the projectile were a big sand bag (weighing 2000 lbs) vs one big granite block? No energy can be put to splinter the block, but also no real ability to impact on a corner (to focus the impact) that you could get from a block.

Something else ... in WWII, weren't the carriers hit by 500lb bombs? That put holes in steel (or iron??) decks, but didn't demolish the ships.

Thx!

TomB

 

[Celebrim]

A couple of points of structural damage per rock. You'd need hundreds of such bombs to wreck a large fortified stone building to the point of collapse. If your goal is to just do damage, maybe kill a few people inside, then yeah, couple of dozen bombs should be adequate to cause some annoyance.

Hey,

Why stop at 200 feet? Aside from accuracy problems, why not 1000', or 10000' feet?

Flight time would be one issue. It would take rather a long time for anything but a perfect manuevarability class flier to ascend to 10000', and then descend again. The higher up you go, the longer between trips, and the longer your bombardment. Also, from 10000', you would as you note have accuracy penalties.

A Something I was wondering ... what difference would it make if the projectile were a big sand bag (weighing 2000 lbs) vs one big granite block?

If the protectile is easily deformable, a greater percentage of the energy of impact will go to deforming the projectile rather than being transferred to the building.

Something else ... in WWII, weren't the carriers hit by 500lb bombs? That put holes in steel (or iron??) decks, but didn't demolish the ships.

Most carrier decks in WWII were wooden. Steel decks weren't the norm except on the big US fast carriers. A 500lb bomb isn't made of rock, which probably would end up shattering on a steel deck, losing a lot of energy in the deformation. The main energy transfer of a 500lb bomb is in the explosive payload. Fifty pounds of squash head plastic explosive would do a lot more damage than a 50 lb rock. That said, 'carrier killers' were generally 1000lb or 2000lb bombs. Five hundred pound bombs were barely adequate versus capital ships, and would require essentially 'critical hits'. Consider the attempts to sink the Yamamoto.