A large number of aluminum single hull (monohull) boat designs (plans) that serve a variety of purposes. these include orcas, outbacks, sitkas, sportsters, sport fishers, crew boats, crab boats, dive boats, and patrol boats.. Why alumi-span® for aluminum docks? since 1956 alumi-span has been a name that people trust. whether it’s a complete boat dock system or the individual components, we manufacture our products using quality methods and materials.. Exceptional custom fixed and floating aluminum boat docks from flotation systems. beautiful, durable, engineered and built to perfection..