His profile continued to rise and, in 1965, he was selected by Cunard as one of the interior designers for their new liner—known initially as Q4, but later to be the "Queen Elizabeth 2"—under construction at the John Brown Shipyard in Glasgow. Bannenberg was allocated to design the Double Room, the Card Room, and some of the First Class suites. His first yacht commission was the sailing yacht "Tiawana", built by the Camper & Nicholsons in Southampton and delivered in 1968. Shortly thereafter, he was commissioned to design a large motor yacht, "Carinthia V", by German retail magnate Helmut Horten. She was shortly followed by the almost identical "Carinthia VI", described as an icon of 20th century yacht design. In a career, which was to extend a further thirty years, Bannenberg designed almost two hundred yacht projects, as well as working on residential projects, aircraft interiors, car interiors, furniture design and hotels.