Castles & Wall tower emplacements

In RTW, any tower along a castle wall would shoot at your troops at all times until you managed to get a unit up on the wall to capture it. For stone walls, the wall towers would even shoot inside the city. (This effect could devastate the enemy though if you capture a few key towers, which would then shoot at their own troops.)

In MTW2, however, this seems to have changed. I've done several assults where I've only taken out 1-2 towers with catapults, but left at least 2 or more intact and in range of my troops as they rush through the gates, yet I've noticed in many cases, the towers don't shoot at me at all.

My best guess is that in order for a tower to shoot at you, there must be troops on a wall nearby, but I am not at all certain this is accurate. Does anyone know for sure?

Not even on the wall, just nearby. The towers have to be "manned", as the manual puts it. Any troops of the settlement owner nearby cause the towers to function. This is important for several reasons: 1) if you gain control of the central square, YOU are the settlement owner and the towers work for you, 2) if their troops retreat/rout, the towers nearby stop shooting, and 3) all they have to do is run a cavalry unit nearby and the towers open up again.

OK, I didn't see that in the manual, thanks.

So, if the units don't even need to be on the walls, what happens when their units are fighting your own nearby the towers?

For example, if after a heavy barrage of artillery, the enemy retreats, and I run several units up to the enemy walls and through the gates, can the AI just flip on the tower turrets again by moving a single group of town militia to the gates again, even if they get destroyed quickly?

I think I like this system better, it gives less of an incentive to sit there and pound away at the towers with your artillery...

Yes, that's right. Example from last night's play: I was assaulting Palermo, as it was the final refuge of those treacherous Sicilians. Inside the citadel was 2 family members. Outside, adjacent to it were their remaining two family members and a single unit of dismounted Norman knights. I had a full army of 20 units: 8 dismounted latinkon, 3 dismounted byzantine lancers, 1 varangian guard, 3 byzantine guard archers, 1 vardariotai, 3 byzantine cavalry and a general. The place where the reinforcements were going to enter was 90 degrees to my left, in the center of the map. There happened to be a gate there. Knowing that they could, at most, "man" two sections of the wall, I deployed in three areas. Over near the gate the reinforcements were going to be making for, I put all my horse archers, all three archers, one latinkon with ladders, and one byanztine lancer. The rest was deployed across the front, ready to assault two different sections. I was going up wherever the towers weren't manned.

As it turned out, they only manned the front gate, so I went up near the reinforcement gate and the right flank. Near the reinforcement gate, I got up top, captured the gate, and then started running all my archers in. When the archers got inside, two of the three went up onto the walls. One of their generals, racing for the gate through the hail of arrows from 4 units of horse archers, followed my last archer unit in through the gate. The towers opened up on me. I killed his general (byzantine guard archers are tough troops) and that shut the towers down when they routed. Well, what happens, but he runs one of the generals inside the town over there to engage the dismounted lancer who just came in the gate, and the towers opened up again.

OK, interesting. So, if I'm understanding you correctly then you can't even capture an enemy tower anymore, only the gates, right? Does capturing the gates buy you anything, especially if you've already blown it apart with your catapults? Maybe just a morale booster?

I'm definitely thinking I need to re-evaluate my assault strategies... they've been working so far, but a halfway defended Castle is a challenge for a full stack of mine. I need to assault my first fortress in Toulouse tonight which may pose a bigger challenge, and I imagine that a Citadel gets really hard. But definitely, it seems like openning up more holes in the walls and destroying less towers is a good way to go...

Well, destroying towers is still good, because then the towers don't fire on you anymore! Capturing a destroyed gate is pointless, but they still give you the message. You're in for a treat with your first fortress. A fortress is a ring castle, with an inner wall as well as well as the outer. Citadels have 3 rings. The enemy will retreat to the next ring once you've taken the one they're currently defending, and the city square is all the way in the center of the innermost ring. Try to conserve the ammo on your siege engines somewhat, and build lots of ladders/rams/siege towers. If you ever run out of ways to get over/through the walls, the battle will instantly end with a loss for you.