40d:Siege engine

Siege engines include the catapult and the ballista. Both are formidable weapons of tremendous range (more than a screen-width) and capable of dealing out horrendous damage. A ballista arrow means immediate death to each and every common creature in its path and will severely injure even a dragon.

Building Siege Engines

In order to build a siege engine, you first need to produce three catapult or ballista parts in the Siege Workshop; you may then build the respective siege engine like any other building. Both tasks require the "Siege Engineering" labor and use the "Engineer" skill. It is not known whether the skill of the dwarf assembling the siege engine has any effect, but the quality of the parts certainly has: siege engines put together from masterpiece parts have a much higher rate of fire and accuracy.

The assembled siege engine is, effectively, a 3x3 building. It cannot be moved about other than by taking it down and re-assembling it at the new site. Siege engines do not impede movement, though, so you don't have to worry about building them in a corridor.

Using Siege Engines (simple)

o will let you change the orientation, whether the siege engine is pointing up / down / left / right. This takes effect immediately, it does not require a dwarf to come and turn the engine.

f toggles the current status between:

• Not In Use: Dwarves with the Siege Operator job will reload unloaded engines and leave them unattended.
• Prepare to Fire: Siege Operators will load the engine and remain stationed for further commands.
• Fire at Will: Siege Operators will fire and load normally.

The dwarves will (re-)load any siege engines that are not currently loaded; there's no way to prevent this short of disabling the labor on all dwarves. Ballistae require ballista arrows (made from wooden logs at the siege workshop, optionally tipped with metal ballista arrow heads made at a forge). Catapults use simple stone as ammunition.

Ammo is destroyed upon being fired, so you can't use catapults for fast stone hauling. They are, however, perfect for clearing away unwanted stone.

Using Siege Engines (advanced)

Safety Warning

Ballistas will kill anything in their path! Ballista arrows appear to hit any units in any square that the head passes through. They are incredibly devastatingly dangerous weapons, and should never be used with friendlies anywhere in their cone of fire, including the space the ballista arrowhead occupies when loaded on the engine. Always designate a restricted traffic cone for a dozen or so tiles along the firing arc and keep dwarves out of the area.

Surprisingly, catapults are relatively safe. Catapult operators will target enemies (and wild animals) if there are any in their field of fire. If not, they will loose the shot in a high arc that misses everything. It is perfectly safe to operate a catapult in the cave: just point it at a nearby wall of solid rock. A nice side effect is that this will in due time clear the whole area of stone.

Using catapults to shoot into the open may provide some meat: as said above, the operators will target animals if there are any. However, elephants don't take nicely if you slay some of them. You also have a slight risk of killing your own dwarves or caravan escorts if they happen to be hunting the selfsame animal (and hence is close to it).

Placement

Siege engines can almost only shoot at targets right in front of them on the same Z-level. The target may deviate only slightly, as the field of fire is about 20-30 degrees wide. Because of the huge blind spots, it is advisable to prepare the position so that the enemy will be channeled through the field of fire.

Siege operators are civilians! They will drop their work and run if the enemy comes too close. You should therefore place the engines behind a moat that will keep the enemy at a safe distance, or shield access to their location in some other fashion.

Siege engines can shoot through fortifications. As fortifications appear provide some protection against incoming bolts and arrows, it's usually a good idea to protect the piece in that way. It only does need a one tile wide fortification to shoot out.

Skill and Quality

The quality of the siege engine parts affects the engine's accuracy and reload time. It is not known whether the siege engine itself also can be of a certain quality. The quality and material of the ammunition (in case of ballista arrows) affects the damage and possibly accuracy as well.

The only way of obtaining high-quality siege engine parts is to have them made by a trained engineer; the only way to train an engineer is to make parts or ammunition. Assembling and disassembling siege engines does not train the engineer skill. Dwarves will occasionally produce masterpieces long before reaching Legendary skill level, but be prepared to waste hundreds of logs until you have three masterpiece parts. Bringing an engineer to Proficient level (the highest you could buy when starting a new fortress) will take about 120 logs. Becoming Legendary requires the wood of 600 trees.

The operator skill may affect accuracy; it certainly affects reload time. It will take a whole month for an unskilled dwarf to load a catapult; a Legendary operator with nearby ammo will get several shots at a running enemy.

Operators are best trained on catapults, as these require nothing but cheap stone for ammo. It is recommended to have a number of dedicated operators that will follow no other line of work, and enough catapults for all of them to play with. As they're often going for a drink or sleep, you may get along with three catapults for four operators, and even two pieces would go a long way. Since the dwarf must hold the heavy stone in his inventory during the entire loading procedure, dwarves that have increased their strength statistic load catapults much more rapidly than others, making them good candidates for operator duty. You should start training early: it can take one year for an operator to become Proficient, and two more years until he finally reaches Legendary level; by then he will have spent 300 rounds.

Loading ballista arrows seems to be much faster than loading catapults, probably due to the much lighter weight of the projectile.

An alternative approach is cross-training any highly-skilled dwarves who aren't doing anything useful at the moment. With a couple levels each in strength and agility, a decent-quality catapult, and an ample supply of ammunition nearby, a dwarf can become a Legendary siege operator within a few seasons at most, giving more flexibility in defense and several more levels for the fortunate dwarf. Rotating Legendary miners out to siege-operation and then to stone-hauling duties sets up an efficient cycle.

In Battle

Ballistas hit any unit that the ballista arrowhead passes through. This makes them an order of magnitude more effective in combat than catapults, which fire in an arc that hits only a few tiles per shot and is nearly useless against anything smaller than a troop of goblins.

A siege engine you want to use for actual defense should be not set to fire at will, as this likely means that it's not loaded and ready at the time you actually need it. You should train your operators on other pieces.

When the time comes, switch off all training engines and set all of the ones you'll be using to prepare to fire so the operators will be on-station; if some of them are currently not loaded, designate them to be disassembled so to prevent your operators from loading the training weapons instead of firing the real ones.

Remember, operators are civilians. They do not care that the fortress is at stake: hunger, thirst and sleep always go first. That's why you trained more operators than you actually need; that's also why you disabled all other work that might distract them. The most effective way to ensure that your operators won't run off is to lock them in with the siege engine when the time comes.

The Hopoate Doctrine

Forums user John Hopoate has written this guide to the effective construction and operation of siege engines:

Please bear in mind that this is VERY long term stuff (10 years). Only by having highly trained siege operators and high quality siege weapons can you shoot accurately.

• Download LabourDF from here:

http://dwarf.lendemaindeveille.com/index.php/Utilities#LabourDF

• Start off with two miners and a woodcutter trained to proficient siege engineer status (the latter costs many starting points so choose your other starting gear and stats wisely)

• After your fortress has about 50 dwarfs, build a siege workshop, place it at the front of your fort near the battlements and designate a custom stockpile within the battlements that can take only ballista arrows. Designate another custom stockpile that can take only regular stone.

• Give your woodcutter dwarfs a custom name (like WOOD) and set their job orders to exclude siege engineering. Change the job orders of your siege engineer dwarf to nothing but siege engineering.

• You'll need wood, lots of wood.

• Get the siege engineer dwarf to build 18 catapult parts, place them inside behind fortifications (which catapults CAN shoot through), designate a custom stockpile of regular stone within the battlements.

• Train six dwarves to legendary status with mining or another fast-training skill, their high attributes are absolutely necessary for siege operating. All operators should have no job orders other than their stat-training and siege operating. When there is no mining to be done, set six catapults to "fire at will"

• After the catapult parts are done, get the siege engineer dwarf to build about 100 wooden ballista arrows, don't bother with metal arrowheads as they'll use 3 pieces of bronze each and that certainly adds up.

• Now that his skill is at a high level, your siege engineer dwarf should be able to build superior quality (*) siege engine parts with about a 75% success rate. Build about 40 catapult parts and 40 ballista parts.

• Build ten catapults and ten ballistas with a MINIMUM of superior quality (*) components in an alternating sequence along your well stocked battlements. Chasm any inferior components.

• By this point your miners/operators should be at a high level of skill, possibly legendary. This gives your superior quality weapons a devastatingly high rate of fire and awesome accuracy.