The aim in the development of the Sevan technology was to provide a unit that would provide ample cargo storage in tanks within the hull, be able to carry a significant topside load and at the same time give favorable motions and accelerations when exposed to harsh environments such as the North Sea wave climate. The cylindrical Sevan unit with its characteristic bilge box offers these capabilities.
The development of the hull and tank configuration is a joined effort requiring competencies on hydrodynamics and stability as well as on structural design. The design is made with focus on safety and robustness, operability and efficiency in construction.
Advanced tools such as the CATIA and the DNV SESAM pack-age including GeniE, WADAM, SESTRA, PULS and XRACT are applied in an iterative process to end up with a design that puts the steel “in the right place”. In addition to the yield and buckling check used as the basis for determining the main scantlings such as plate thickness and stiffener cross section, extensive fatigue analyses are also included in the design process to explicitly control the fatigue life of critical details such as mooring equipment foundations and side structure subject to dynamic sea pressures.