This is a winch mount we use in our Brover. Its designed to hold a 25mm 9V gear motor. You'd find them in MakeBlock robotic kits. or order them. Use anything you can tie to the shaft for a cable.. We use 50lb fishing line and a gnarly treble hook for the grapple.
Works really, really well.
When/if you print, the more infill you use the stronger your winch is.
Please note.. If you're making one of these and use our specs you can potentially tear apart what ever your "hooked" up to..