Nice choices of art, am I right in thinking you drew the map? Because, that's great too.
I like the idea of how long players take impacting The Captain's condition when they find them, that really raises the stakes if you sell that to them from the beginning. The size references you used were perfect.
I love the tables on page 15, those are useful in and out of this adventure. The areas were well described, I especially liked 9. Feast Room - the anglerfish (Boglin) lurking beneath the surface would be quite ominous for players.
I liked all the Rival Adventurers and Hirelings personalities and a nice addition would be stat blocks for them, to save the GM a few steps.