I’ve never used a Hawaiian sling before (a spearfishing tool), and thought I’d make one for the next coast trip. It’s made of PVC piping 15mm and 3/8″ surgical tubing. The shafts are 5mm x 900mm high carbon steel with a notch cut into the back like an arrow.
I used zip ties to hold everything together, we’ll see how long they last in the salt water. Make sure you glue the PVC pipe well together!