For a prototype this is a very complete version, and also a very beautiful one! The view of the brown tumblehome is fantastic! I'd suggest though that you increased the tumblehome at the bow Whilst I think the height is OK, as galleons could have a very high forecastle,
yours seems a bit bulky and squarish, as the the last few bricks are basically vertical.
I specially like your unique stern. We usually get to see heavy sterns with lots of gold and yellow details and yours is simple and elegant. Good job on that! The lines seen from the back seem almost perfect, where the almost is those 1x2 inverted brown slopes you have used to build the stern upwards from the prefab hull. The angle should be a little more complicated than uniformly 45º, as you can easily check in Nuestra Senora:
So if you are considering rebuilding the stern these are good ideas to keep in mind