Design, computer lofting, and kits for welded aluminum boats. specmar inc (previously specialty marine contractors) is an aluminum boat design, lofting, and kit company.. Boat plans and kits 400 to choose from; bruce roberts; boatplans; boat kits; steel boat plans; aluminum boat plans; fiberglass boat plans; plywood boatbuilding plans. Designs available in aluminum…. aluminum is also a superb material for boatbuilding by the person qualified in aluminum welding. aluminum boats using welded marine.