You should look for reference pictures on the type of old-school ship you're making.
The wall underneath the 'windows'/portholes is too heavily shaded.
You should take into account the source of lighting (the Moon)- its direction and intensity- to have the piece be more atmospheric.
For example, the chimneys are not taking that into account
The clouds also look as if not belonging in the scene; they look as if part of a collage. You should also shade them in acknowledgement of the Moon's lightning (clouds closer to the Moon should be clearer, and those farther away would be darker)