Hey Tom, wonderful entry there :) This is definitely one of the smallest yet coolest-looking ships I've seen recently, great job!
I love the no-nonsense, no-cannons approach, that's a hardcore trader right there

The captain's cabin also looks very cozy - extra points there for adding playability by making the top come off so easily. My only gripe with the ship's design is the fact that there's a bit too much hull space at the bow that cannot be used due to the way you've placed the brown tiles to cover up the front mast... Freeing some of that space up would probably make the whole ship look even better! I'm also not sure about the height at which the sail is positioned at - perhaps you could have added another one just below the sail on top to make it look more realistic? Or another front sail? The way the single sail is positioned now, I'd guess it just makes use of 40% of the mast's actual height...
As to the rocks, I like how small they are - it makes the whole MOC look as if the ship's captain was navigating through some treacherous straits... Sea rocks don't usually have to be huge to be dangerous ;) Perhaps you could still try and position one of
those diagonally - I think that would add to the feeling of movement here. If you choose to go for the ship docking scene suggested by Tereglith though, I think you should try an off-loading scene, with crates being hauled off her under the captain's supervision (and yes, a monkey wouldn't go amiss in such a scene ;) ).
Regardless of whether or how you modify this MOC though, I still think it's one of the top contenders in the medium category. Lovely entry Tom :) Best of luck in the competition!