sentences:  He was also the author of over forty books and numerous articles on maritime history, many of them produced in collaboration with his second wife, Ann Giffard.His best-known book was his two-volume "The Merchant Schooners" (1951–57).He also published "Westcountrymen In Prince Edward's Isle" (1967), on Devon shipbuilders in Canada, and "Boats And Boatmen Of Pakistan" (1971).