The Zeppelin NT is a "semi-rigid" airship. It is unlike both the original Zeppelins that had a rigid skeleton and non-rigid blimps. It has an internal triangular truss made of graphite-reinforced plastic and three longitudinal girders made of welded aluminium which connect the triangular elements along the length of the frame. Additionally, the structure is tightened with aramid cords to provide for extra rigidity. All major components, such as the engines, control cabin and the steering fins, are mounted upon the structure; this allows maneuverability to be maintained even in the event of envelope pressure being lost. The whole structure weighs only about .