Sonntag Fins are produced in full Carbon Composite technology in female-moulds only. Unidirectional, bi-diagonal and multiaxial carbon fiber is used in different textures and different carbon filament types.
A closed loop development and design system allows to control and link each step starting with the specification, simulation by CFD and FEM, 2D&3D design of fins and moulds, production of mould, lay-up definition, production and testing on the bench and on water. By that a “special” customer requirement can be easily implemented into the dedicated fin by adapting some of the variable parameter (length, rake, bending&torsion stiffness). Outcome is a real “engineered” fin with a very efficient characteristic.
Sonntag Fins owns all machinery like high speed CNC-mills, computerized and pneumatically actuated test benches, 3D CAD/CAM computer stations, etc. This allows quick design&verification loops and also reduces the costs for new designs. Each new model and lay-up has to proof its mechanical strength by long-time endurance tests. Here the fin is treated by 200% of normal load for more than 50.000 cycles; during test the bending stiffness is real-time monitored to detect weaknesses.
Each fin produced is tested on a test bench on its mechanical characteristics to guarantee that the fin fulfills the general and the specific customer requirements. Data is acquired, computed and stored by computer. The results are documented in a test certificate delivered together with the fin. The key-data are engraved onto the base of each fin by a CNC-machine.