This was a project I made for a demonstration speech for college. It’s called a Floating Trebuchet (treb-yoo-shet), it is said to be one of the most efficient designs for a trebuchet. Everything is made out of steel except for the arm itself that I used a piece of 3/4" aluminum tubing to reduce weight and increase speed. I was pretty surprised how hard this thing throws when I finished it so it definitely exceeded my expectations and was a lot of fun to build. Used Millermatic 210.