The game does have a lot of text-based files like some of the good flight sims. You can alter the subs' *.upc (upcge for an Axis), eqp & sns files, which 'link' to nodes in other respective files. The *.dat (main 3D artwork & controllers), zon (damage), sim ('drives' the AI), val (wakes & some special FX), cam (the 'camera' file) and dsd (sound FX) are among those, somewhat editable wth
S3ditor, which is beyond my understanding. The bigger dds files are the skins, the smaller ones are for the nav map display (and one for the RecMan for other vessels). You'll find the 'turms' or 'conns' or 'sails' (pick your vernacular) in the Objects folder, and guns & other 'weapons' and radar doo-dads in the Library folder, or one of its sub-folders (pun intended)...
... and "Welcome to SubSim!"
