Grappling Hook - Steel Core

This is the more complicated version of my grappling hook that I actually printed before I designed the simpler one here.

I had intended to use M4 threaded machine screw for the core, but none is available near me, so I used a threaded steel rod I found in the basement, which is likely a 10 Ga rod. I threaded the rod through the holes, thus setting a thread, then gently threaded the whole ensemble on. A nut is on either end of the threaded rod.

I printed with 1.2mm thk top & bottom, and 2mm thk walls. 5% infill. ~15hr print. It pulled up my auntie's kayak just fine. It does bounce a bit though.