Done in UltraFractal 5.04. No imported images. The only manipulation was due to a bug in the program, that refuses to render small elements. So had to render the stern part with the windows and the lanterns bigger, than scaled down in Photoshop. Otherwise UltraFractal seems perfectly suitable to make concrete ships.
Gees, one never learns... Just received an email by the UltraFractal author, the incredible Frederik Slijkerman and he solved my problem. For very small elements one has to change the drawing mode from "Guessing" to some of the other 2. This made my day as new more complex works will come then
So with this in mind the picture could be done entirely as a raw fractal!