New Speed Fin Releases

Today I heard about 3 speed fins going into production. This got to be a new achievement, a milestone for speedsurfing. Again prove speedsurfing is alive and back.

The Sonntag Fins GPS_4 is the speedfin with conventional outline, the main thing we tested for was a good performance and safety/grip. The GPS_4 can be tweaked both in rake and lay-up from a flat water water powerhouse up to a chaotic off-/onshore grippy and safe fin. The Sonntag Fins GPS_5 is a new widebase design, made to make windsurfing possible in extreme shallow flat water. The GPS_5 has a wide range of working angle of attack, in other words its not needed to be the best most fit windsurfer in the world to handle this widebase. Read More about Sonntag Fins

Type X
The 3th new speedfin release is a complet new concept. From Black Project Fins. The Type X. Widebase AND asymmetrical, this is new.
But there is more, you don't order a type X in lenght! No you can order for the speed you aim for. A fin for 40kn, 45kn or 50kn. Both for starboard and port tack. Read More about the Black Project Type X

Erik Loots

Erik is windsurfer for 10+ years. In his daily life he is professional in construction dewatering, advisor, troubleshooter. Erik likes adventures, explore and to challenge himself. During his life he is trying to get the best out of it and have respect for the earth, nature and future generations. The modern world is about sharing, in this blog Erik shares his experiences, selfreflection and lessons learned.


  1. What are the differences with the C3 Slingshot? Gtz, Luc

  2. I don't know really the differences between C3 slingshot and Sonntag GPS_5. Only a few logical differences... C3 is made out of G10 and Sonntag out of carbon, however on such thick short and widebased fin material doesn't really influence the fin characteristics.

    Also I guess the profile-thickness should be about the same. But profile, rake and other stuff like lay-up behaviour difference between C3 Slingshot and Sonntag GPS_5 is unknown and ofcourse interesting to test one day.

    The only thing we did is use the good idea of a widebase and start developing a design (GPS_5) that works in a wide range of conditions and still being competitive. Herefor we used some profile-testing (using different profiles), because outline and stiffness are very limited parameters for the widebase design. The winner was a foil-profile that works in a wide range of angle of attack. For me the GPS_5 will be the fin when the wind picks up above 30kn average on open spots or 35-40kn average on inland spots.


  3. How much do the GPS-5 cost?