This book's setting rolls along on the high seas. Have you noticed each book has a different setting? That's on purpose. WotN was Tripp's practice series before retiring and writing full time. He wanted to try different settings: wooded, riverine and urban, confined prison, and marine. Subterranean is next. 

Tripp spent countless hours as a young man sailing on his boss's 42 foot sloop in Casco Bay, Maine. Against all likelihood, he never ended up in the water, watching the boat sail away.

Tripp owns or has fired black powder weapons, including flintlocks, cannons, and muskets. He doesn't have a mortar, which is what Shent built out of a bell. He should have one, though. 

The boarding ramp Shent and Tisa designed was a real thing, invented by the Romans and called a corvus. The average man thinks about the Roman Empire about once a day. Tripp thinks we're still in the roman period prophesied in Daniel 2. Just look at our governments, capital buildings, and divided cultures. 

Today, the earth is 70% covered in water with continents mostly surrounded by ocean. But pre-flood, no one knows for sure how much ocean existed. Not zero. We know they existed because of the fossils. Tripp guessed at 30%. If so, it seems likely the concept of continents didn't exist until post-flood. Before that, oceans would have been surrounded by connected land, not the other way around. Tripp doesn't really know but likes to think about it. 

The leviathan was a real animal, as described in the bible. Tripp doesn't ascribe to any particular fossil specimen (dinosaur or otherwise) being the actual leviathan. Maybe one could be it. Maybe its fossil hasn't been found. Maybe they all survived the flood only to die out afterwards. He doesn't know. Instead, he used the actual biblical text to describe the creature, which may have been something like a mosasaur. 

The Bilge got bumped by a megalodon. Tripp's glad they're gone. Sharks freak him out.

The Dread Spin and related chapters were included to add adventure, dinosaurs, and pirates to the story. You don't want to read about being on ship for the entire book. But also, the idea of great matts of vegetation floating on the oceans checks with the massive amounts of coal we have today.