Being ordered to disarm a ship is a common scenario in custom campaigns. Sometimes, however, this task turns out to be confusing. Under a FREDding point of view, disarming a ship means destroying all the turrets on a ship. Most of the times, however, it's not clear if the player is supposed to destroy the weapons subsystem or disarm each and all of the turrets. It's not clear from the briefing/mission messages/directives.
On rare occasions, taking down only a given number of turrets is enough to cause a breakdown of all weapons systems. This, of course, can only be represented via a wise use of SEXPs.
This is an easy way to script a strike whose intent is disarming a ship. The is-disarmed-delay SEXP alone is enough to handle this—it will become true if all turrets of the specified ship are destroyed.
Everything has to be clarified during the briefing and/or during the mission. It is very important to tell the player that he has to take down the turrets and not the weapons subsystem. This will prevent the player from depleting his payload to disable that subsystem, only to find out that he had to take down the turrets instead.
Payloads are to be planned according to the situation. The number of turret the target may have is various, so it is suggested to rely on a multitude of small weapons, such as the Stiletto II. The subsystem disruptor weapon must be given as a default loadout, especially when the relevant orders are absent from the briefing. The player has no idea what will happen in the mission, the initial loadout is an important first clue. If it's a bonus objective that remains undeclared, then it's probably better to make Stilettos, Akhetons optional.
Destroying the weapons subsystem
Destroying the weapons subsystem on a ship will reduce the aiming capabilities of that ship's turrets. In theory, taking down that subsystem is not enough to effectively shut down all weapon systems. It's not rare, however, to disarm a ship with this kind of approach.
As always, the player needs to know what he has to do. If the target is the weapons subsystem and not the turrets, the orders must be specific. It is better to use the "destroy weapons subsystem" phrase instead of the "destroy weapons," because the former is unambiguous.
In order to justify this choice, it's possible to make changes to the plot. A ship diverting all powers through a given turret, a damaged ship or a sabotaged one may be vulnerable to the destruction of the weapons subsystem. In order to represent this, the is-subsystem-destroyed-delay SEXP has to be linked with turret-lock-all or turret-lock (depending on the situation). Additionally, the advanced turret-change-weapon SEXP may be used to "downgrade" weapons and represent a consistent cut in energy supplies. If a ship has been totally disarmed and doesn't pose a threat of any kind, it may be the case of changing its IFF.
The loadout can be various. Because there's only one weapons subsystem turret per ship, it's possible to employ tactics based on the deployment of warheads like the Cyclops. This depends on the situation and, of course, on the size of that ship. Cruiser-size vessels and below should be disarmed with weapons designed primarily against subsystems.