Three stars from me.
I couldn't quite figure out what was wrong with the book even while rating it. I almost liked it. I am sure I liked it. It's nicely written and I loved the universe and the characters, except for Cel. What a bitch, honestly. Throwing her brother to the wolves, convinced in her mind, that these pirates are brutal vicious monsters. Nice move, sis. I suspect she held a grudge against Prince Whatshisname or some such.
But back to my rating. It all became clear when I started tagging the book:
Adventure - almost. There was this one cliff-walk and some (very smooth) sailing.
Cross dressing - almost. There was this one "costume prank" in the beginning and one sex scene in the end.
Enemies to lovers - almost. The Pirate was not as rough and monstrous, The Prince wasn't as unwilling.
Nautical - almost. Yep, they were on a boat and they sailed. But I didn't get to see or experience it enough through any of the characters.
Rainbows and lollipops - even that fell short (thanks to Cel. I really disliked her).
Fantasy - was it? Might as well be an AU or a futuristic setting, definitely a different planet. Sci-fi then?
Pirates - almost. I mean I heard about those things a lot, but once again - did I see them doing their arrrgh-arrrgh? What a disappointment :(
I also considered:
Prisoner/kidnapping/abduction/captive - nope. None of them worked. Even "hostage" didn't really quite fit.
Dark - nope. There was one little paragraph, but it did not spread on the rest of the story.
Dub-con - nope again (see "enemies to lovers").