just for the "f" of it, decided to have an closer look:
- Stern, I don't think it should be flat, it should be rater of two different angle, the lower section is right up and down, while the top section is slightly inward.
https://rogueadventurer.files.wordpress ... eme-73.jpg
- The hull depth: you have drawn the ship with hull depth of approx 4 meters. Formidable class hull depth is 6 meters (39px).
https://en.wikipedia.org/wiki/Formidable-class_frigate
- rest is just small details, like for example how porthole looks like they could perhaps look better with dark grey corners.
Oh the shape of you'r ruder is quit wrong...