Houseboat plans can give you a start in planning your houseboat building project. check out these free or low cost houseboat plans. Specmar inc (previously specialty marine contractors) is an aluminum boat design, lofting, and kt company. we have a large product line including aluminum drift boats. Clark craft offers hundreds of boat plans, design patterns and complete boat kits, and a full line of boat building supplies and accessories for the amateur boatbuilder..