Sonntag-Fins is measuring the bending stiffness and twist at multiple points along the fin length to determine the bending and twist characteristic of a specific fin. Both dimensions are measured for each fin produced on an numerical controlled and automatically actuated test bench. During the test the measurement values are acquired and processed by a computer and stored in a database.

For bending stiffness the words like high, medium, soft are related to a description for the customer making the technical description (listed above) easier understandable. These terms always needs to be related to the fin length and other structural data. A stiff 50cm slalom fin is normally always softer than a soft 25cm slalom fin. This makes it not so easy to understand the real differences. Therefore a physical method delivering real numbers is a better solution – but unfortunately – more difficult for the customer to follow the idea behind.

Of course we also measure the torsional stiffness and the geometric twist angle on our test bench. But these measurements are much more complicated in execution and description and the test setup and process of data acquisition is company confidential.

We hope that this explanation helps to understand the backgrounds behind our measurement and classification scheme.

The pictures are showing an older test bench. The fully automated ,new, numerical controlled test bench is not shown as the concept is company confidential (sorry :o).