Coincidentally, I'm also 1/2 way through this book as of today. And I have to say, it's very much worth the read. As Fletcher500 said, Excellent.
He described some of the solid aspects of the book. I would also add it is much more "meaty" in detail, history, and concept than the average tale of this type. She avoids trying to make heroes or tear-jerk personal back stories of the lost mariners, and really focuses on the issues, events, and context.
I am not familiar with her writing, but I am going to pay attention for her name in the future.