In the movie, Bernard and Bianca, the two mice from "The Rescuers", travel to Australia to find a young boy named Cody who has been kidnapped. Cody had been lost in the outback after a plane crash, and his pet mouse, Bernard, was separated from him during the crash.
While not the exact scenario you described (Bernard wasn't lost from a shipwrecked boat), it's a very similar situation with a mouse being lost from a crash.