The inner space frame is made of titanium. For modular design, the vehicle is separated into six sections, including payload. To minimize flow resistance while cruising, the vehicle has a hydrodynamic efficient streamlined form. Every section consists of a box and a front and rear bolted flange. The boxes are made of two millimeter thick titanium sheets bend to its specific form. To reduce the construction weight lightening holes are placed into the frame sheets, with marginal sacrifice of stiffness. For an easy handling and flexibility of the vehicle configuration, all space frame joints are screwed. Neutral buoyancy is achieved by a 6 000 m depth rated syntactic foam which is placed between the space frame and the outer streamline shell. To form a light, robust and hydrodynamically efficient vehicle hull several thermoplastic polymer shells are mounted onto the titanium frame.
Because of the pressure tolerant design there are no centered gas filled pressure hulls to support any additional lift on certain locations in water. Due to this fact a careful location of all possible weights and displacements of all internal devices is required for an accurate buoyancy trim. For the development of DNS Pegel a CAD program was used to define the weights and displacements of all internal devices.
The vehicle center comprises a cylindrical flooded payload section variable in length. Currently the payload is 0.6 m in length and contains either a profiler winch system for long term tests or an ORE acoustic transponder with Ultra – Short Baseline (USBL) function for tracking purposes during dive tests. For further wet payload items like CTD sensors or side scan sonars additional space is available within this section. Because of the overall pressure tolerant design the payload can be changed without any respect of pressure hulls which makes the vehicle highly flexible in use.