Jörg Kock has developed a system with which the position of powerbox fins can be varied - this could mean a noticeable improvement in driving performance, especially with seaweed fins.
Jörg, a long time ago there was a power trim system that allowed the fin position to be changed in a rail. It didn't catch on. What motivated you to develop a power box system that allows the fin to be moved?
I'm a mechanical engineer in the automotive industry and started my own business five years ago, partly to have more time to surf. I used the long coronavirus period to push ahead with some ideas that have been on my mind for a long time. One of them was to improve the Powerbox system.
What were the problems?
I have noticed with my own boards that the fin position does not always fit perfectly, depending on the area of use. This mainly affects boards with a power box, where the fin position is naturally fixed. As a hobby surfer, you unfortunately don't have the ideal board for every wind range and have to use your boards in different conditions. For example, I use my Fanatic FreeWave or my Lorch Freemoveboard in light winds in flat water, but also in strong winds in small waves. It would be ideal if you could push the fin back in less wind and with larger sails to achieve more directional stability. For manoeuvres and wave riding, it would be ideal to move the fin forward to improve the turning characteristics. This led to the idea of developing a system for power boxes that would allow the fin to be moved.
"Moving the fin significantly extends the range of use of many all-round boards."Jörg Kock
How does your system actually work?
The system is inspired by the Power Trim system of recent years. A new fin system is of course not feasible on the market until all the major suppliers join in. That's why I started adapting the head of the fin step by step so that the fin can be moved in the power box. I milled the head of the fin smaller and inserted two more threads. You now have the option of installing the Powerbox fin in the normal position and offset by 1.5 centimetres forwards or backwards. As the fin head is naturally smaller than the box after machining, you need suitable adapters to fill the gaps.
Could your system also be a sensible solution for seagrass fins?
Yes, absolutely. With seagrass fins, you generally have the problem that the pressure point of the fin moves very far back due to the inclination - which impairs glide performance, turning characteristics and, above all, upwind performance. With my system, you can mount the seagrass fin in the box either 1.5 or three centimetres further forward, which reduces the negative effect.
Machining the fin head is apparently not that easy. How should the conversion be done?
There are two possibilities: As part of a co-operation with Maui Ultra Fins, these fins can be purchased from me with an already modified head and matching adapter. It is also possible to modify an existing "favourite fin". If you want, you can send me your seagrass or standard fin, which will be re-milled accordingly, fitted with additional threaded inserts and sent back with a suitable adapter. The fins should be available from summer 2021.
Contact us: joerg-windsurfing@online.de
Thank you Jörg for the interview!
