A while ago I did a review video on the Apneaman Freediving Buoy (Apneautic).
Below I have embedded the video for you to watch, but there is one subject in particular I still wanted to discuss here, since I did not discuss it in depth in the video: the rope. I will keep it short though, and let the video speak for itself.
There are different opinions on what properties the ideal freediving rope should have. Basically there are a couple of main separating criteria: (1) does it float or not; (2) is it 10mm or 12mm thick; and (3) does it stretch a little or the least amount possible.
(1) Whether the line floats or not mostly influences the handling after the dive. I think it is mainly a personal preference whether you find it more convenient to knot it back up and/or put it back into the buoy when it sinks down or comes to the surface after you have pulled up the bottom weight.
(2) The thickness of the line is also a matter of personal preference. I like the rope a bit thicker. It just feels nicer in the hand when grabbing it. That said: I’m a pretty big fellow.
(3) The elasticity (or possible percentage of elongation) of the rope is especially a factor in deep dives. Simply put: if the line is 100 meters long and has a possible 4% elongation that is a possible 4 meters extra you might unintentionally get. Of course the negative influence of this on your dive is very much dependant on the sort of bottom weight or anchoring you use and whether you have or have not taken this factor in consideration. Ideally, though, you have the least amount of elongation possible.