Welkin Weasels, book 3 : Windjammer Run
Garry Kilworth1999

Sylver and his band of weasels take to the high seas in search of the humans who mysteriously deserted the land of Welkin many years ago. On their tail is the seasick Sheriff Falshed, commanded by the stoat rulers to stop Sylver at any cost. And if that's not bad enough, behind them is a ship crammed to the gunwales with bloodthirsty rats, convinced that Sylver is secretly hunting a pirate's treasure...