Introduction: Kayaking Prosthetics

Hello and welcome to the Cambridge Bio-Augmentation System’s OpenSource kayaking prosthetic. This project was born out of John Willis’ Road to Rio Challenge, where he participated in every Olympic and Paralympic sport in the lead up to the Rio 2016 Olympics/Paralympics. He wanted to show that sport doesn’t have boundaries and no matter the impairment, able bodied and impaired people can inclusively play together. So it is very fitting that the devices that we designed to help John hold sporting equipment, we are now releasing into the public so that true to John’s goals, the boundaries of sport are eliminated.

Step 1: Design Notes

Paddle Shaft

– These devices will fit on the commonly available 32.7mm shaft diameter paddles.

3D Printing

– The minimum printer requirements are:

Print Material (in order of preference): PLA, ABS

Bed Size: 150mm x 150mm x 140mm (height)

Printing Resolution: 0.2mm

Shell: Thick (2mm)

Infill: 30%

– We recommend looking on for printers that can make these parts at a low cost.

Step 2: Selecting Your Devices

This Instructable is made up of two separate devices ('Paddle Ball' and 'Paddle Hoop') that can be mixed and matched depending on your amputation level. Please refer to the table to identify what you will need.

NOTE: If you have a unilateral transhumeral amputation you may find it easier to use a short metal rod in combination with a paddle hoop that you put your remaining arm in.

Step 3: Paddle Hoop

Step 4: Labeled Device: Paddle Hoop

1- 5mm Foam

- Cut to 50mm x 90mm

2- Arm Curve Component (3D Printed Part)

3- Bike Inner Tube (2x)

- Cut to 50mm x 90mm

4- Clamp Component (3D Printed Part)

5- Metal Hoop (Search for “round section circle”)

- 100mm diameter

- 8mm rod diameter

6- Bike Handlebar Tape

7- M5 bolt (4x)

- Fully Threaded

- 50mm

Step 5: Paddle Hoop STL Files

Step 6: Manufacturing Paddle Hoop

- Wrap bike handlebar tape two thirds of the way around the metal hoop.

Step 7: Manufacturing Paddle Hoop

- Glue one of the pre-cut inner tubes to the clamp component.

- When glue has set, cut the inner tube away around the slot section.

- Allow to cure.

Step 8: Manufacturing Paddle Hoop

- Glue the other pre-cut inner tube the the arm curve component.

- Glue the pre-cut foam to the arm curve component.

- Tap the marked holes with an M5 thread.

- Allow to cure

Step 9: Manufacturing Paddle Hoop

- Slide the hoop over the paddle

Step 10: Manufacturing Paddle Hoop

- Put the clamp component on the paddle, ensuring the hoop fits into the slotted section.

Step 11: Manufacturing Paddle Hoop

- Slide the arm curve between the hoop and paddle ensuring that the small cutout in the arm curve component and the slotted section in the clamp component align.

Step 12: Manufacturing Paddle Hoop

- Screw the clamp and arm curve components together using the M5 screws.

Step 13: Paddle Hoop Full Assembly and Use

• To use, slide your residual limb into the space between the hoop an the arm curve.

• If you find the space to fit your arm in too tight/loose then the hoop can be replaced with a wide range of hoop diameters (also available from Alternatively the foam padding size can be increased.

Step 14: Paddle Ball

Step 15: Labeled Device: Paddle Ball

1- Metal Rod

- Dimensioning will be covered in steps 20 to 23

2- Ball Component (3D Printed Part)

3- Housing Component (3D Printed Part)

4- Bike Inner Tube (2x)

- Cut to 50mm x 20mm

5- Clamp Component (3D Printed Part)

6- M5 Bolt (4x)

- 40mm

- Fully Threaded

Step 16: Paddle Ball STL Files

Step 17: Manufacturing Paddle Ball

- Glue the inner tube to the clamp component.

- With an M5 thread, tap the holes marked.

Step 18: Manufacturing Paddle Ball

- Glue the inner tube to the clamp component.

Step 19: Manufacturing Paddle Ball

- Locate the clamp and housing components on either side of the paddle shaft.

- Screw the components together with the M5 bolts.

Step 20: Manufacturing Paddle Ball

- Thread the metal rod so it attaches into your socket (please see your prosthetist for thread dimensions).

Common threads are:

- UK made prosthetics- 3/8 inch Whitworth.

- US made prosthetics- 1/2 inch.

- EU made prosthetics- M12.

Step 21: Manufacturing Paddle Ball

- Fit the paddle ball device to the paddle (and fit the paddle hoop if your amputation requires it).

- Have the paddle held in front, and parallel to your shoulders.

- If you are a unilateral amputee, then this should be held at arms length.

- If you are using a paddle hoop, then this should be at elbows length.

- If you are using a dual paddle ball, then this should be a comfortable distance.

- While in the position measure between the end of your socket and the inside curved surface of the housing (shown in the image).

Step 22: Manufacturing Paddle Ball

- Minus 11mm from the measured number. Mark this new measurement on the rod when measured from the top of the threaded end (shown in diagram)

- Cut the top 18mm on the non threaded end to Ø9.5mm (as shown in the non shaded section of the image).

Step 23: Manufacturing Paddle Ball

- Glue the ball component to the 18mm, Ø9.5mm section created in the last step.

- Allow to cure.

- NOTE: Your rod may not look like the image shown however, if it fits the ball, fits into your socket, and is the right length, everything is correct.

Step 24: Paddle Ball Full Assembly and Use

• To assemble:

– Screw the metal rod into your socket.

• The ball on the metal rod is designed to click in and out of the housing component.

Step 25: Additional Information


– Cambridge Bio-Augmentation Systems does not accept any liability in relation to these devices, or any of their remixed variations. Any breakage, injury or death are solely the risk of the user and by manufacturing you agree to relinquish Cambridge Bio-Augmentation systems of any responsibility.


– When using these devices we recommend that you take appropriate precautions, particularly if you’ve never kayaked before. Make sure you ALWAYS wear a life jacket, and until you feel comfortable make sure you have competent kayakers close by.

The OpenSource license

– These devices are released under the creative commons license: attribute – noncommercial – sharealike.


- Any quires please contact