I wanted more from this.
There are excellent ideas here--sirens, 20th-century pirates, ocean travel, and the like--but none of them are fleshed out in a way that's satisfying to me. We start the story thinking it'll be about Nerene and Sande, but then they're separated. Then we think it'll be about Nerene and her bonding with her possible father, Lord Osperacy, but then the Melily subplot is introduced. This subplot becomes the main plot, and then Cressit's subplot is brought in. New reveals then make the story all about Cressit, Melily, and evading their old life, until that's thwarted and Nerene has to move again.
We end up back with Sande and Nerene, without any knowledge about what happened to Sande over the course of their separation, nor do we have any indication of if she'll end up with either Sande or Cressit (not that she has to end up with either). I could have forgiven this if I felt the plot had some focus. But, ultimately, this story's decision to flit between different plotlines without developing the supporting characters or the surrounding world made this whole read feel like a waste of time for me.