John Marples

John Marples (born 1944) is a pioneering American multihull sailboat and powerboat designer, mechanical engineer, boatbuilder, and author renowned for his innovative wood-epoxy composite designs that emphasize strength, seaworthiness, and affordability for both recreational and commercial use. Born in Heswall, England, during World War II, Marples immigrated to the U.S. as a child, spending his early years in northern New Jersey before his family relocated to southern California. A graduate of California State Polytechnic University with a degree in mechanical engineering, he has drafted over 40 vessels ranging from 7 to 64 feet, blending practical engineering with hands-on sailing experience that includes five Pacific Ocean crossings, one Atlantic crossing, and over 30,000 bluewater miles of racing, cruising, and deliveries. Operating from a part-time design office in Penobscot, Maine, through Marples Marine (established around 1980), he continues to offer plans, consultations, and U.S. Coast Guard (USCG) certification services for multihulls, having assisted with over 30 passenger-carrying vessels. His work, often in collaboration with multihull legend Jim Brown, has produced thousands of boats worldwide, earning acclaim for democratizing high-performance multihulls via accessible construction methods like constant camber.