how to add new lockers in my campaign ship?

[Blackburn]

or is it impossible

[アンジェル]

Originally posted by Blackburn:

or is it impossible

By normal means there is no way. You can use crates instead.
By editing means

a) Using mods like EK: Utility which allow you to craft shelves

b) Using a save game editor to add stuff via the submarine editor to your submarine
https://ignis05.github.io/baro-save-editor/

The save game editor is so useful...