feeling of a third hand that would accurately let the rope run through a grab with a very light touch. I still think that the feeling is unique.But as it is a "light touch" knot it takes care and attention to make it a safe knot. It has to be tied very cautiously and checked regularly for burns.The minimum diameter of rope shouldn't be less than 8.5mm and the mantel mustn't be burned or damaged at any point. The Machard tresse is made out of a loop. The simple knot tied with a single strand is called a Valdotain tresse. I have not worked with it so I don't have much information about it. But Kay-Olaf Busemann is using this specific knot. The advantage seems to be that the diameter can be close to the diameter of the climbing line and still be efficient.Tests have been done on the Machard tresse, the Blake and the 3-laps Prusik. Frederic Mathias has worked on those tests with "Cousin", a French rope company, with the following results. The climbing line used for the tests was 1/2 inch High Vee Blue from New England ropes. The Blake was made out of the same rope. The 3-laps Prusik was made out of a 10mm diameter dynamic kernmantel rope (mountaineering rope).Two tests were done. A static test was performed by pulling on the friction knot straight down on a single rope. When breakage appeared it was the climbing line that was broken first where it was constricted by the friction knot. The tensile strength with the Blake was 1987 daN at the breaking point, for the Prusik it was 2054 daN. The result with the Machard was particular. This knot started slipping at 600 daN, then catch, then slip again and so on. The double advantage being that it doesn't break the climbing rope and would have the capacity to keep an eventual shock load lower than 600 daN. So in case of a fall, a part of the energy would be absorbed by the knot which would keep the shock load to a safe level for body.The dynamic test reproduced actual working conditions. A 80 kg m...
