Twin Tension Knot Pass Using a Figure 8 Loop – In lowering systems configured as twin tension rope systems, passing a knot becomes more manageable—particularly when the knot locations are intentionally staggered between the two lines. This strategy allows for momentary load transfer to one side, effectively transforming the system into a main and belay configuration. This method enhances operational control and is particularly useful with descent devices designed for high-efficiency, bi-directional load management.
Devices like the CMC Clutch and Petzl MPD are ideal for this application, although the technique can be applied with other twin tension-compatible descent control devices as well. Here’s how to execute a smooth, safe knot pass in such a system.
Step-by-Step: Twin Tension Knot Pass with a Figure 8 Loop
Step 1: Pause the Lowering Process
Stop lowering operations when the knot approaches within approximately 0.5 meters above the descent device (e.g., Clutch or MPD). This distance ensures enough space to maneuver the knot without interference from the device’s internal cam or sheave.
Step 2: Tie and Anchor a Figure 8 Loop
About 1 meter above the knot, tie a secure figure 8 loop. Clip this loop to a temporary anchor point, which will now carry the load on this rope while the knot is adjusted.
Step 3: Transfer the Load to the Opposite Rope
Resume lowering until the entire load is transferred to the opposite rope system. At this stage, one side is bearing the full weight, and the line with the knot is unweighted.
Now, remove the rope from the descent device and re-thread it so that the knot is now positioned below the device, allowing for an uninterrupted path for continued descent.
Step 4: Disconnect and Resume Lowering
Once the line is re-rigged, detach the figure 8 loop from the temporary anchor and untie it. Begin lowering again, gradually allowing both ropes to re-equalize tension and return to full twin-tensioned function.
Why This Method Works
This technique allows the rescue team to manage knots with minimal interruption to operations. It leverages the flexibility of twin tension systems while maintaining continuous load control. By using a figure 8 loop and controlled re-rigging, knot passage becomes a simple, repeatable process without requiring additional hardware or complex changeovers.
It’s an essential skill for advanced rope rescue personnel operating under NFPA 1006 Technician-Level standards, especially in real-world applications where terrain, rope length, or damage demands mid-system transitions.
Mastering this knot pass approach reinforces system flexibility, safety under tension, and efficiency when managing multiple lines during technical lowering operations.
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