Raiders’ Ransom, by Emily Diamond, was published in 2009 by Chicken House/Scholastic.
It’s the 23rd century, and much of England—what once was England—is underwater. Poor Lilly is out fishing with her trusty first mate, Cat, when greedy raiders pillage the town—and kidnap the Prime Minister’s daughter. Her village blamed, Lilly decides to find the girl. Off she sails, in secret. And with a ransom: a mysterious talking jewel. If she saves the Prime Minister’s daughter, she might just stop a war. Little does Lilly know that it will take more than grit to outwit the tricky, treacherous pirate tribes!