A littoral ship would be a defensive variant of an existing vessel. It may have an extra slot or slightly improved bonuses, except for one thing -
It can’t jump to adjacent systems, period and they warp faster. They act strictly as system defense.
Let me add, fot clarity’s sake - I am not interested in game balance or “geejm belluns”. I am interested in adding sorely realism, narrative design, immersivity, world building. I am not interested in getting elaborate discussions about “how the goons would immediately abuse this feature and bla bla bla”. I think this concept makes sense, strictly from a world building viewpoint, and that’s sufficient for me.