The Lifeboat (by Charlotte Rogan)
In fact, it dragged. The days on the lifeboat are described in excruciating detail and no new information really emerges. I didn't need all my questions answered in the end but none of them were, really -- so many loose threads. I feel like I "know" what happened, and will put it in the next paragraph, but... [SPOILERS]
Mrs. Fleming dies early on, and it seems fairly clear that Grace killed her based on her accusations about buying her way onto the lifeboat. So the revelation at the end (that she probably also killed Mary Ann for the same reason) doesn't really pack a punch. I already figured that out. I enjoyed piecing together the rest though -- the box probably containing Grace's jewelry, her fake love for Henry, etc.[/SPOILERS]
It's not bad, I guess, but slow going in the middle and the "reveal" reveals nothing much.