I say go with normalmap and maybe parallax on the "bumps". Don't know how you would do them from the start thought :P Maybe try sculpting them, don't know..
@gsokol Thanks for the input I'll remodel/sculpt a couple more rocks later today @Matroskin Whoa! Great reference, thanks! For texturing the submarine I'm planning on doing a tileable texture, I tried doing it with just a single large texture and i wasn't having too much luck with it. I think I have a pretty decent…