The "TackleClamp" gripping hitch.
There are two ways we can enhance the effectiveness of a multi-wrap friction hitch, tied around a spar/pole, and used to withstand a lengthwise pull
1. Increase the number of wraps.
2. Increase the force with which those wraps nip the spar/pole.
Now, there are two ways we can achieve the 2.
A. Wrap the "under" wraps with other, "over" wraps - i.e. wraps that lie on an outer shell, on a second layer around the central core of the spar/pole.
B1. Increase the tensile force with which the ends of the wraps are being pulled , and,
B2. keep them under constant tension, so they nip the spare/pole at their core more forcefully.
B1. To pull the two ends of a rope segment more forcefully/effectively, we may use the "mechanical advantage" offered by a block-and-tackle rope mechanism. In fact, we do not even need the blocks/pulleys, because we can use bights formed on the ends of this segment (i.e, a bight-and-tackle rope mechanism).
B2. To secure the two ends of a rope segment that we want to keep under constant tension, we may drive them in between two interlinked opposed bights that are also kept under constant tension. The friction forces generated in the area in between the two tips of those bights from where ends pass through, are sufficient to not let them slip through.
The "TackleClamp hitch" is a multi-wrap friction hitch that incorporates both mechanisms, B1 and B2, in order to increase the force with which the wraps nip the spar/pole they are tied around. Thus, the total friction forces induced by this hitch on the spar/pole are greater than by the other known friction hitches.
It should be stressed that, in order a segment of rope can accumulate tensile forces and not run the danger to release them with a small displacement of its ends towards each other,
1. The rope segment should be sufficiently long. Most of the times, with commonly used spars/poles and ropes, this requirement means that we should use as many wraps as we can, within the limits imposed by practical considerations. Certainly, one wrap would not probably be enough, most of the times.
2. The material of the rope should be able to be elongated under tension as much as possible. Nylon is a material that can be elongated a lot, yet retain its tensile characteristics, and, moreover, not suffer from creep or fatigue.
A slight modification that might be helpfull in some applications, is to let the "lower" end to pass through the "upper" bight once more, or vice versa. This is easily done, because those bights remain sufficiently wide open - as they already turn around one rope diameter, and their two legs remain parallel. By doing this, we have both standing ends pass through the same bight as they exit the knot s nub. I do not know which of the two alternatives ( i.e., to have them pass through the "higher" or the "lower" bight, at their last passage through them) will pull the hitch LESS effectively along the spar/pole.
( I have listened the song of the seductresses Sirens, and dared to place a name, as a label, for this hitch. ( Actually, this name was proposed by a friend of mine, who have tied the hitch...). I would be glad if there are any other proposals, which might be able to name this hitch even more descriptively.)
( I post here only the already published pictures. I plan to take new, better pictures with some new material that I will put my hands on in the near future. Here I had tried to repeat, in other words, what was the "ratio" that drove me to this knot, so it does not look something "random", that had suddently fell from the sky...Knots are just rope mechanisms, there is nothing magical in the conception of their structure.)
P.S. I have just remembered a well known tool that is used on tubes and pipes, and which works in a very similar way the TackleClamp gripping hitch works : Not by increasing the contact area between the rope and the spar/pole ( as it is often done, by increasing the number of the wraps ), but by increasing the tension of the wraped rope segment. It is called "strap wrench", and one can see many variations of it with the help of Google Images. The same tool is used to replace spin-on oil filters in cars, and it is called "oil filter wrench" (strap type). The TackleClamp hitch is nothing but a rope-made, multi-strap "strap wrench" - where the mechanism to pre-tension the straps is not a lever mechanism, but a bight-and-tackle rope mechanism.