fion9x3owns The ships's folder is located at users\username\Documents\My Games\Cosmoteer\Saved Ships
the subfolder names can be anything you want just avoid too exotic characters.
The ships can only be loaded in creative mod, MP, or bought in Bounty Hunter game but won't spawn as enemies.
You look for them like how you normally open and look for your ships. If they are in a subfolder then click on the small arrows and or hamburger button to open up more choices or to navigate the folders.
Ship save files must be in the format: name.ship.png
The name can be anything even having it's own format like [Lafiel] test.ship.png