Please print a tensioner where your rope just barely fits in the hole(s), otherwise the pinching from the smaller diameter section will not work as intended
If your intentions are for long term use, set height scale of the tensioner by 130%-150%. An example of long term use is hammock hanging (8h+ under large load). For use cases such as this, please consider ABS or ASA - PLA might be too weak
Please use maximum amount of walls if strength is needed (to achieve a solid part without)
I have provided examples of settings i think would work well, but i do encourage editing the .f3d file to get the strength you desire
How to edit parameters:

The author remixed this model.
remix of my own model - made it fully parametric and cleaned up the f3d file - added variant with smaller diameter in the middle hole