Purrfect Voyage — Ruth J. Hartman

Kitty Carter is used to getting into strange situations when she chases her cat, Arthur. But this latest escapade is just too much! When Arthur chases a mouse at the marina while she's doing research for her book, she follows him down the dock and onto a yacht. Not entirely her plan, since she falls down some stairs and hits her head, and wakes to find herself out to sea. And she and Arthur aren't the only ones on board!