The spinefins concept

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Basics

BLIPFINS designs and handcrafts windsurfing racing hydrofoils. To guarantee high performance hydrofoils BLIPFINS are built using the molded fin method. So far BLIPFIN tests on the water have lead to different hydrofoil layer setups for standard molded fins depending on windsurfer type and the conditions. In open water lake conditions top speeds of more than 30 [knts] have been reached with standard molded fin prototypes.

In general, there are two types of fins on the market, milled fins and molded fins. The most important design parameters of a fin are its profile and its stiffness that together lead to a characteristic stiffness distribution. For milled fins the stiffness distribution can practically only be defined by the profile of the fin. Whereas the molded fins method makes it possible to additionally influence the stiffness by arranging fibers in the desired directions and by using different types of fibers. Both production methods lead to the effect that a thicker profile goes along with a higher stiffness. In order to tackle this effect BLIPFINS has design the SPINEFIN concept.

THE SPINEFIN CONCEPT

It is the aim of the BLIPFINS Spinefin concept that the stiffness and the profile can be customized separately. The concept of the Spinefin design is differs from milled fin and mold fin designs.

The blade of the Spinefin is made of at least two components, the spine and the profile. The spine can be made as a molded or milled component. We prefer the molded system, as it creates the highest possible stiffness on very thin profiles and furthermore a better distribution of flexural and torsional stiffness can be obtained. The spine layer is the component mainly responsible for the stiffness of the fin. The outer layer gives the fin the outline and the profile.

 

 

 

Layer one, Layer two, Fin blade complete

 

spine

Using the Spinefin method stiffness, the outline and the profile are designed more independently. The user has the advantage to customize the fin design more precisely for his/her riding style and the riding conditions. Once you found your favourite flex pattern, different profiles can be applied on spines with your favourite spine stiffness.

In a bionic version of the Spinefin concept the outer profile layer can be designed with improved hydrodynamic properties using a soft material beneath the surface. Inspired by the shark skin´s composition a softer layer below the surface can improve the hydrodynamic behavior of the fin by minimizing turbulences that occur on hard surfaces.Therefore less drag, earlier planning and higher top speeds are possible.  A wider, more tolerant range of use should be achieved, as peak pressures will be absorbed. We basically think, that all the copying of rough „sharkskin“ structure is a good way, but only a part of the story, as nature always applies these structured surfaces on semi soft skins that are backed by an elastic layer. To avoid a too soft trailing edge, a harder casting resin is used in the affected area, which is realized by a three component version.

First Spinefins will be tested around may 2014.

 

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