I remember awhile ago (tho it may have been a different forum) I mentioned an idea for making static ships have systems that where dependant on each other. That is to say if the reactors down, like Jeremy said, the turrents wouldn't work. The way I'd picture that working (if you don't want fancy codes) would be for each turret to have only a few shots in them, maybe like 3 (if its a slow shooting gun). Now the turret gets constantly resupplied by the main reactor, which is a destroyable object that constantly resupplys certain weapons (the turrets) with ammo. So when the reactors up, the turrets never run out of ammo. Reactor gets destroyed (maybe externally by torpedoes or internally by charges) and the guns run outa juice. Bam.

Futurama: You Can't Prove it Won't Happen