To the OP:
That was an excellent summary of a siege, one well worth reading by Toady. Some of the game/interface problems I see it pointing out are:
- Extremely awkward interface for switching sparring and battle weapons.
- Non-existent dwarf "keep out of danger during a seige" AI.
- Lopsided relation of the path distances within a fort to the distance your dwarves can spot invaders from.
- Unreliability of military dwarves, with even the few methods the game provides to keep dwarves on station (backpacks and flasks) being cumbersome and sometimes buggy.
Also, are you using squads? If you are, then don't. The entire squad becomes useless if the captain wants to guzzle.
General concept of defence
A fortress should have three military regions:
1) a "secure zone", with everything needed for survival, where no invader will walk into except over the dead bodies of your military,
2) a "battle zone", where you engage enemies, and
3) a "zone of approach", where you whittle down enemies (by fire, with traps, etc.) or simply make them march a long enough distance to buy your dwarves enough time to muster fully-equipped.
Keeping civilians out of mischief
Half-measures don't cut it. Don't even bother with the "civilians stay inside" order.
- Lockable doors should define the borders of the "secure zone". All civilians who might potentially wander outside that zone should be conscripted, marched inside that zone, and locked in there for the duration of the siege. Either keep them drafted or make certain that the zone is properly shut down. Watch for strays throughout the battle!
- Train all civilians up to at least a Novice military skill (wrestling is ideal), so that they don't get unhappy when you do conscript them. Wrestling skill will also keep them alive longer if they get ambushed.
The gatehouse
The most useful defensive construction I've ever discovered is the fortified gatehouse. It is a large marksdwarf firing position, placed so as to give those inside a clear field of fire at least 20 grids long at anything approaching the entrance. It has a lockable door and an ammo depot. Marksdwarves enter, I lock the door, and they stay for the entire fight - no wandering off to eat or drink!
Here is my first attempt at a gatehouse. Although it lacks certain features later found useful, a awful lot of goblins and trolls died in its kill zone.
Protecting your dwarves (inc. Wrestling versus Crossbow training)
Train up wrestling and shield use as priorities, with occasional rounds of training on crossbows as a side-item. Crossbows are so effective that even (normal) skill marksdwarves are deadly; the problem is keeping them alive in the return fire. Wrestling, shield use, and fortifications are how you do this.
Armor is a nice-to-have for marksdwarves (for melee dwarves it's vital of course). You needn't wait for your Armorsmith to skill up; put someone on bone-carving and another on leatherworking as both of these materials can be used for light and serviceable temporary protection that's a lot better than nothing.
Training versus battle weapons
I use separate, enclosed stockpiles. One stockpile holds battle weapons, the other holds training weapons. Material and quality are carefully controlled in both; anything not suitable for either stockpile gets stashed someplace else.
When I need to re-equip the troops quickly, I put them on duty, set them to wrestling (so that they drop their current weapon for the haulers to clean up), and station them inside the appropriate weapons stockpile. Those who make it there get re-equipped and sent off to the battle muster point.
Melt returns
I wrote part of the wiki page. It is correct to the best of my knowledge and recent testing.
You do NOT get back a straight 1/3rd of the metal - that's merely a (very rough) average. It all depends on item size. Leggings and shields have an unusually large size for armor items that require only one bar to make, and therefore melt for a larger fraction of the metal used. Boots are not quite as effective.
[ May 28, 2008: Message edited by: Fedor ]