Looking around for a solution to lift the power cable from the deck of my boat (to avoid rolling away on it), I was not very successful. So I figured out what I needed, what the properties of this double-hook were to be, and here it is. I sits pretty well locked on a 9.5mm cable, clinging to a 5.5mm PVC-clad wire of the sea fence. Thus, the hooks can stay on the cable when you haul it in to sail. Make multiple of these according to your demands.

I did not yet make a scad-version but added the basic dxf file of the thing to facilitate individual variations. Make sure the distance between the two bulges of the lower part is slightly smaller than your cable's outer diameter.

I used Fusion360 to loft the contour to 8mm or so (does not matter, just make it handy) and round the edges.

Printed in PETG. It is very stable also under intense UV light.
0.4mm nozzle, alfawise U 30 printer, Simplify3D, 25% honeycomb filling. 3 perimeters, 5 top and bottom layers. 0.8mm rounding radius. No support. 250°C nozzle, 80°bed