Sea Dogs (and a Cat) — Susan Lyons

Solo and Spike live on farms near the sea. One night, they answer the call coming from Spyglass Cove and join up with Captain Rollo's motley crew of sea dogs. They sail off on a mission to rescue Princess Esme from pirates, not realizing that Mittens, a pesky cat from Solo's farm, has stowed away. Once she's discovered, Mittens finds herself and Solo right in the midst of the rescue plans. Spike has his part to play as well, and the trio must prove themselves worthy sea dogs (and a cat) if they want to get home again.