Yo Ho. I love me some pirate stuff, even though I haven't yet actually played Pirate Borg. I'm not going to review this for specific playability within the system because I'm not familiar enough.
I can see how each zone flows naturally into the next. I think you give just enough information about those zones for a GM to be able to set the scene, though I felt it was a little bit light on exposition until I saw the table on the final page for describing the area around the players. Honestly, I think that table is my favorite thing you have here.
I think you absolutely nail the weird fiction vibe with the areas you've included in the doc. I feel like a boat adventure is the perfect opportunity to move from one big set piece into another and so on and so on, so I'm glad that you kept it tightly focused on what's interesting about the places the crew will see as they go on their nightmare adventure.
From a visual perspective, the cover is great. I think the font is just a little bit difficult to read, but not overwhelmingly so. I just think the bold is a little bit heavy and the letters are close together on page 2 and the top half of page 4. Page 3 feels fine to me though.