Our aluminum rigid-hull inflatable boats (ribs) are exceptionally stable with a smooth ride and good handling. they have self-baling decks and are of rugged construction.. Design, computer lofting, and kits for welded aluminum boats. specmar inc (previously specialty marine contractors) is an aluminum boat design, lofting, and kit company.. Click pictures below to view large sized picture. super stable in open water. dockitjet inflatable sponsons adds a safety sponson bumper around the edge of the pwc in.