The Black Diamond Atc Guide is a widely recognized and frequently used piece of climbing equipment, particularly favored in multi-pitch rock climbing scenarios. Its guide mode functionality allows climbers to belay a second climber directly from the anchor, enhancing both safety and comfort. A key benefit of guide mode is its auto-locking feature, designed to automatically arrest a fall by cinching the climbing ropes against the belay ropes when loaded. However, recent experiences suggest a potential failure in this auto-locking mechanism when using thinner ropes.
The Incident: Slippage with Thin Ropes in Guide Mode
During a recent multi-pitch climb, I utilized a Black Diamond ATC Guide in guide mode to belay my partner from above. We were using two 7.8 mm half ropes. Unexpectedly, when my partner experienced a fall, the auto-locking mechanism failed to engage as intended. Instead of the climbing ropes clamping down on top of the belay ropes, they slipped next to them within the ATC’s cage. This resulted in a slow, uncontrolled slippage of the ropes, gradually lowering my partner.
Attempting to manually brake the device proved challenging due to the inverted brake direction in guide mode, which would require pulling towards the rock face. Fortunately, the slippage was minimal, and by applying significant force to the brake strand, combined with rope-on-rope friction, I managed to halt the descent. Despite the positive outcome, the experience was unsettling, raising concerns about the reliability of the auto-locking feature under these conditions.
Technical Specifications and Real-World Performance
It’s important to note that 7.8 mm ropes are indeed thin, but they fall within the manufacturer’s specified minimum rope diameter of 7.7 mm for the Black Diamond ATC Guide. This incident, therefore, occurred during what should be considered proper use of the equipment, highlighting a potential safety issue that warrants attention.
One possible explanation is wear and tear on my specific ATC Guide. After several years of use, it’s conceivable that the device’s tolerances have changed, potentially increasing the minimum rope diameter required for reliable auto-locking in guide mode. However, my ATC Guide is only a few years old and exhibits a typical amount of wear for its age.
Recommendations for Enhanced Safety with ATC Guide and Thin Ropes
Based on this experience, it is prudent to exercise caution when using the Black Diamond ATC Guide in guide mode with thin ropes. While further testing is needed to definitively establish a safe minimum rope diameter, it is advisable to consider using ropes of 8.0 mm diameter or greater for belaying in guide mode. This recommendation, although not based on rigorous testing, is a precautionary measure derived from a real-world incident.
It is also crucial to investigate whether similar issues exist with other “guiding” belay devices, such as the Petzl Reverso, to determine if this potential auto-locking failure is specific to the ATC Guide or a more general concern with guide mode devices and thin ropes.
For climbers who frequently use thin ropes, exploring alternative belay techniques or devices that offer enhanced security with thinner diameters may be beneficial. Further research and user feedback are essential to develop best practices for safe climbing with thin ropes and guide mode belay devices. If you have any insights or suggestions on improving safety when using thin ropes in such scenarios, your comments and experiences would be highly valuable to the climbing community.
