Hi Christian, here’s a video showing how I modified my paddle (it sounds like Uncle Fred did something similar): https://www.diypackraft.com/2019/09/19/convert-a-kayak-paddle-to-a-packraft-paddle/
Also, here’s a post about how another person made his own paddle from carbon fiber tubes and sheets, in case you want to try making one from scratch: https://www.diypackraft.com/2017/03/27/diy-5-piece-carbon-paddle/