Castle siege questions. (Long)

[Kizarvexius]

I have some questions about breaking castle walls/gates/portcullis and how to handle it.

Here's the (very) basics:

The party has taken over a keep that is on the border of two kingdoms. There is a secret chamber beneath the keep that the party is not aware of yet that holds a powerful magic item. The keep also borders two separate woodland communities. The 'evil,' woods has a centaur/druid who believes that the item can benefit her centaur clan and give them the upper hand in a long-standing war that is occurring with the centaur of the 'good,' woodland. She has the ability to call one large and two medium earth elementals to attempt to break into the keep so her troops (5 trained barbarian Trolls, 15 mercenary wild elven fighters, an elven sorcerer, and a Human Ranger.) can rush in and take the keep. There's more to it, but it's not pertinent to the question.

My questions are:

1.) The keep walls are 10' thick of stone. The outside of the walls were stone shaped smooth as an apology by a young adult Copper Dragon that has befriended the party's druid and occasionally shows up to cause havoc. I consider this superior masonry for the purposes of the wall type chart in the DMG. This would give the stone the following characteristics: (At 1' thick: Break DC of 35, Hardness of 8, and 90 hit points per 10'X10' section.) So in my estimation (unless I'm doing it wrong,) is that the 10' thick wall has 90 hit points per 10' section total. So a large earth elemental with it's earth mastery and two slam attacks (2d8 +10 (+1 with mastery) would take a bit (3-6 rounds) to pound through it. Am I doing this correctly? Also, since it's strength is 25, and can be boosted with spells (bull's strength, etc.), the elemental would most likely attempt a direct break against the wall. If he succeeds in defeating the DC, does that mean he shatters only 1' of wall? If he misses the DC, how much Damage is done to the wall? The damage from one slam? If he has 2 attacks/round, does he get to try beat the break DC each time, or is that a full round action that negates all other attacks? I'm trying to see what would be quicker and if I'm doing it right. If he attempts the break, it would take him 10 rounds if only allowed one try/round. However, just slamming the wall twice per round would bring it down pretty quick anyway. For RP, it would be a better description if layers of wall were to "shatter under the explosive force of the elemental" than if the wall were to gradually crumble.

2.) The Door problem: The DMG says that a strong wooden door at 2 inches thick has a hardness of 5, 20hit points, and a break DC of 23. The Keep has two 10' tall heavy doors made of oak. The doors are 2' thick. Since the DMG does not clarify an area scale like with stone (10'X10' section,) doing the math makes these doors have 240 hit points. This seems excessive. I would build a keep out of doors if this were the case. Am I doing something wrong? And again, the question is if the earth elemental beats the break DC of the door, does he get through the door, or succeed in breaking 2 inches of thickness of the door? I am considering the door 'locked,' because of the locking bar behind it, which gives a break DC of 25. Well within a large Earth Elemental's ability check. Also, does he get 2 attempts/round or is it a full round action? Striking an object is a standard action, right?

3.) The Portcullis problem: The keep has a portcullis made of iron bars and crossbeams. The bars are 6 inches thick. The DMG states that a 2 inch thickness of iron portcullis has a hardness of 10, 60 hit points, and a locked break DC of 25 to Lift it. This would give my iron portcullis 180 hit points. Again, the question is if the earth elemental beats the break DC of the portcullis, does he lift the portcullis, or just outright fail? Striking an object is a standard action, right? So two attacks=two attempts?

I haven't even explored the two medium elementals helping, but it seems to me that all the elementals would go to the door if it were just a break DC. The stone walls would take too long in the larger scope of things. One last thin, the PC's have been allocated 25 men to help man the keep before the full complement of troop can arrive. The walls each have 4 ballistae and a magically turn able (variation of Tenser's floating disc of old...) catapult in the middle of the courtyard.

Any help would be greatly appreciated.

-Mike

 

[Darklone]

In case of the elementals, why bother with walls or door if you can go down below them?

 

[CCamfield]

Ok, I'm no expert, but:

On p136 of the PHB a 1' thick masonry wall has 90 hit points. The stats for a stone wall (540 hp for a 3' wall) make it clear that you calculate hps for walls by multiplying thickness by hp/inch. That would give the 10' thick masonry wall 900 hit points, which is on the right scale with the doors.

Given the thickness of the doors and the rating of 10 hp/inch on p136, that would indeed give them 240 hit points, and your stats for your highly impressive portcullis are also correct. (I have trouble imagining a 2' thick door if it wasn't a drawbridge, myself.)

Judging by these thicknesses and the presence of seige weapons, I would say that this is a very strong and important castle. By comparison Carnaervon Castle, one of those built to hem in the Welsh, had walls 20' thick at their strongest point. If you meant this to be a border fort, I think you overdid things slightly.

I have to run, but I'm pretty sure that if you're trying to break down a door (shoulder-charging it etc) you do not do any damage to the door itself, on success or failure. You're trying to open it rather than chop it down with an axe. However for the wall I would just say that it's impossible to quickly break it down, and the elemental would have to start hammering away against its hardness of 8. It'd take a looooooong time.

 

[AuraSeer]

(At 1' thick: Break DC of 35, Hardness of 8, and 90 hit points per 10'X10' section.) So in my estimation (unless I'm doing it wrong,) is that the 10' thick wall has 90 hit points per 10' section total.

Not quite.
It has 90 hp per 10'x10'x1' volume. To get through the entire thickness of the wall, you need to do 900 points of damage. Your elemental would take more than an hour to bash all the way through it.

The Break DC of 35 is also far too low. A 3' wall of hewn stone has Break DC 50; masonry is weaker than hewn stone, but this wall is three times as thick, so I'd be comfortable using DC 50 here as well. Even an elder earth elemental (Str 33) or the strongest dragon (Str 47) would have no hope of success; a monster with Str 70 would succeed only 5% of the time.

(Aside: remember that for a break check, you roll a d20 and add your strength bonus. I've seen some people use the whole strength score, which is not correct, and makes walls and doors far too fragile.)

A Break DC is all or nothing. Either you succeed and break the entire object, or you have no effect at all. You cannot Break-check your way through a stone wall 1' at a time.

2.) The Door problem
The DMG says that a strong wooden door at 2 inches thick has a hardness of 5, 20hit points, and a break DC of 23. [...]doing the math makes these doors have 240 hit points.

240 hp sounds about right. They have about 25% as many hp as an equivalent section of wall, and they're far easier to damage because of their lower hardness.

Again though, you need to increase the Break DC when you increase the thickness. The DC 25 in the book is for a normal-thickness door with a normal-sized bar. A 2'-thick castle gate is a whole other animal, and I'd call it DC 30.

This Break DC is obtainable by your forces. The large elemental has a strength bonus of +7; if the Medium elementals assist, they each grant a +2 bonus from Aid Another. That's a total bonus of +11, which means they could bash through the gate on a roll of 19.

Also, does he get 2 attempts/round or is it a full round action? Striking an object is a standard action, right?

Striking an object-- ie, attacking to do damage-- works like a normal attack. Attempting a Strength check is not explicitly given an action type, but it's clearly not a melee attack, so I allow only one attempt per round.

Anyway, if you have spellcasters on your team, why are you bothering with these crude physical attacks? The easy way into a castle involves Passwall or Disintegrate. Poof, instant breach.

Maybe your sorcerer doesn't have those spells and can't get them on scrolls. In that case, forget the earth elementals, and have your druid summon air elementals instead. Since they can fly, they can carry troops to the top of the walls and make hash of the ballista crews.

 

[Kizarvexius]

Thanks for the help, everyone.

In regards to earth elementals tunneling, I don’t see any reference to this in the MM. I know they used to be able to, but I don’t see it in the rules. I could use them that way, but I’m trying to keep pretty close to the rules to learn 3E. I’m a 1st edition Dinosaur.

In regards to setting wall hit points, your description is exactly how I thought it was done, but under ‘breaking items’ and under ‘Walls,’ on the chart there is an asterisk for hit points. When you check the asterisk, you see “*Per 10-ft.-by-10ft. section.” This is what is confusing me.

The main concern I still have is that the door break DC is much more attainable than breaking it down, and even the very strong portcullis seems to be fairly easy to lift with it’s DC. I still need to know about multiple tries and such also.

I agree. This small keep is built like a old, hardened castle, but it holds a powerful magic item and the ‘evil,’ woods has a very old black dragon deep within it that occasionally likes to knock down human structures. There’s a lot more to the keep.

-Mike

 

[AuraSeer]

The main concern I still have is that the door break DC is much more attainable than breaking it down, and even the very strong portcullis seems to be fairly easy to lift with it’s DC.

This is how it should be, for creatures with very high Strength.

Think about an interior door in your own RL house. They're probably rather thin in comparison to your strength. If you wanted to open one that was locked, you'd kick it once really hard, and it'd probably pop right open. If you instead took an axe to it, you'd have to swing several times (and spend multiple rounds) to make a big enough hole.

However, if you were faced with a BIG door, you might lack the strength to bash it open by pure force. In that case, you'd need to spend the time to reduce its hit points and chop a hole in it.

The difference between "flimsy, kickable door" and "big damn unkickable door" depends on the basher's strength. Strong monsters, like elementals, are just better at breaking objects than humans are.

I still need to know about multiple tries and such also.

For Breaking an Object?
One try per round. You can usually keep trying until you succeed, or until you get bored with rolling. Since this is a combat situation, taking 10 and taking 20 are not allowed.

 

[Kizarvexius]

Thank you, AuraSeer.

I really appreciate it. Duh on my part on the 10’X10’X1’. That makes sense.

Do you arbitrarily assign a greater DC to increasing thickness, or do you use a self-made formula or reference?

Oh, the Earth Elementals are used because of my Campaign world. Instead of gods there are primal manifestations Air/Earth/Fire/Water/War/Magic and Death. The druidess is a druid of earth and gets bonuses to any earth-based spells. There are penalties involved for casting outside your religion for clerics and druids.

She is also not a great tactician. She has limited troops and has about 400 yards of clearing (from the forest to the keep) to advance through. The attack will occur at night. She is attempting to attack with the elementals on the South side to divert attention away from her Troops advance. Trolls will be covered with various spells like invisibility and barkskin as they advance, but trolls are stupid and tend to pop out of invisibility by attacking prematurely. She is also trying to get in close enough to use her spells and magical bow against the people on the battlements. She fears the ballista, though. The sorcerer has many buffing spells but is a wild elf and tends to be a little twitchy, so she uses him to bolster troops and cast ‘behind the lines.’ The human ranger will be attempting to coordinate the 15 wild elves on yet another wall. They will be visible and randomly running to the keeps walls. They are protected with potions. This Ranger will be invisible, and will later attempt to gain entrance by feigning fear and pleading for admittance later. (He will be chased to the doors by a troll.)

The druidess is not stupid, though. She has other tricks for later. She wants to hit and fade the keep, knowing that the elementals can most likely destroy the gates and force the party and men at arms to spend time building it back up. Her animal companions are ravens that she uses as spies at all times. She will harass the party always. At night and during the day, attempting to draw them out into the forest. (Which they wisely refuse to do. The druid in the party says it would be folly. =P)

Again, very basic descriptions of motive and plans. But she is a centaur, also. Not very versed in siege. She asks the Ranger’s opinion, but his back story is not at all rich with keeps and castles. Her motive is to eventually destroy this keep to allow the forest to re-encroach from the clearing that took place a long time ago. And to wrest the magic item from the keep. Whatever it may be.

Thanks again, AuraSeer. I was thinking of only one try/round for break DC also, but I wasn’t sure if this was right.

One more question on an unrelated (and probably beaten to death) topic: Can a druid move through his own entanglement in 3E?

-Mike

 

[IceBear]

Just curious, but is there anything in the "Stronghold Builder's Guide" on this. I have it, but haven't read it yet (I've told you I'm easily parted from my money )

IceBear

 

[Shayuri]

>>In regards to earth elementals tunneling, I don’t see any reference to this in the MM. I know they used to be able to, but I don’t see it in the rules. I could use them that way, but I’m trying to keep pretty close to the rules to learn 3E. I’m a 1st edition Dinosaur.

-- It's still there in 3rd, it's just not listed as a power, per se. Check out the Movement line in the stat block. You'll see "Burrowing" listed there. This means they can move at the listed speed through the earth.

>>One more question on an unrelated (and probably beaten to death) topic: Can a druid move through his own entanglement in 3E?

-- I don't THINK so, no. I don't see anything in the spell description that excludes the caster from its effects, and the Druid power to pass without a trace doesn't apply to magically affected vegetation.

To amplify some of the comments of others though, magic can make a castle largely obsolete. Those trolls could just as easily have Fly as Invisibility, for example. Or both! Elementals of Earth and Air can get in without worrying about the walls at all. In a fantasy setting, a curtain wall is mainly just an inconvenience for a large army. A smaller force with appropriate magic will pierce straight to the keep...and a good castle design will anticipate that.

 

[AuraSeer]

If the attackers have access to potions, Spider Climb would be a great choice. They won't need to open the gates, or even bring scaling ladders.