No abstract

All manufacturers of synthetic mountaineering ropes provide chemically coated ropes in order to reduce their water uptake in a wet environment. As common static test methods for the investigation of the water repellent behavior of ropes do not move or bend the ropes, the measured water uptakes are usually below about 10%. In this study we have investigated the water uptake of coated ropes under conditions that are closer to practice conditions than all other methods. Our results show that commercially coated ropes provide a sufficient water repellent behavior as long as the ropes are not in practical use with, for example, carabiners. As soon as the ropes sustain a practical use, the water is worked through the sheath into the core of the ropes so that the water uptake is comparable to the values of uncoated ropes. As a result, the safety performance is decreased both in terms of the number of drops sustained and the impact load. Furthermore, we have investigated experimental coatings and found one chemical (a wax-based coating) and one physical (plastic tape between the sheath and the core of the rope) coating, which were both able to reduce the water uptake even in dynamic conditions.