(covers information from an alternate timeline)
While on a voyage, his ship was hit by a typhoon in the Pacific, and everyone back in England thought the crew were killed. Eight months later however, Cray sailed into London harbor with what remained of his ship. Not much was left, a few planks and half a sail, but Cray had managed to get his crew home.
In an alternate timeline, Commander Chakotay recalled the above story, when he gave Kathryn Janeway a present for her birthday - a replica of the pocket watch worn by Cray. He thought the relation between that and the events USS Voyager was enduring at the time. (VOY: "Year of Hell")