The Retraction Spring Design

The larger and heavier the paddle head size, the greater the effort is required to rotate the paddles out of the water at the end of each stroke. Hence, a retraction spring was added to the mechanism for this design. 

I used a paddle board paddle head on this model. I used an extension spring but it needs to be a torsion spring.

If the retraction spring is used, friction is created between the track and the slide box so the paddle slide box must have wheels or another design for the mechanism to operate smoothly. I tried stainless steel wheels on the paddle slide box but they should be rubber or other compound because these corroded quickly.

This is the first generation Supski made out of PVC and HDPE plastic sheets and I am demonstrating the extension spring. I do not recall if the extension spring got overstretched or not. I used a 45 degree angle on this design but eventually adopted the ninety degree.

This is the second generation Supski and I am demonstrating how the spring works.

The components that make up the Supski and how it operates. 

This is a design for the torsion spring which will replace the extension spring.

Another manufacturer came up with this shape which might work better than wheels. This could attach to existing boards.

Maybe some shape like this could be embedded into a hard board.

Alternatives for making parts with molds.