I am glad you got it working 😁
However I am not quite sure I am following... did you set up a custom ship vehicle in [CGMZ] Custom Vehicles? Or were you trying to make a custom vehicle with the id "ship"? Custom vehicles should only be used for custom vehicles, not for the default vehicles, and you should stay away from the ids "boat" "ship" and "airship" for your custom vehicles. Likewise, this plugin should only be used to add interiors to the 3 default vehicles.