Done just in photshop with some help from my colleagues.
While the technical execution of the art is nearly flawless (use more orange for the sunset light), the ships are still full of constructional errors.
I am in maritime archaeology and specialize in ship reconstructions of ancient Roman and medieval Byzantine ships. In your case, I suspect that you used some Imai model kits of ancient Roman ships as source. But those model kits are full of errors because they never had any person with deeper knowledge as part of their staff, they always just copied what they saw somewhere without being able to know if a source was correct or wrong. I think, that is the reason why all movies and PC games are using inaccurate or strange ships, instead of the correct authentic ones. And trust me, the authentic ships are even more impressive.
I love the attention given to the smallest of details. the shadows and lights are amazing. Yeah this is truly a masterpiece.