Jagdgeschwader-51 What I mean is making it possible for the cannons to have armor placed in front of it or have scaffolding to allow bullets and lasers past. This way you could make cannons that can have the same damage and also allows armor in places where it couldn't be placed. I am not saying make the armor go on the cannon, as that would hinder the cannon more then scaffolding mixed with armor.
Example.
You want heavily armored ship.
The cannons you only want to shoot in one direction.
You could then place armor either in front of it or beside it.
All the sides you want the cannons or other weapons to fire would have scaffolding ports.