Twin Tension System Knot Pass for Raising Operations – The Twin Tension System (TTS) offers a significant advantage in rope rescue operations, particularly when navigating knot passing during raising evolutions. This method uses dual mainlines and staggered knot positions to allow continuous control of the load, enabling one side of the system to manage tension while the other side undergoes adjustment.
By design, the TTS enables fluid transitions, reduces downtime, and maintains critical redundancy throughout the lift. When paired with high-efficiency devices like the CMC Clutch, MPD, or similar mechanical advantage systems, the process becomes both safer and more efficient.
Here’s a fully expanded, step-by-step breakdown of how to conduct a knot pass using the Twin Tension System in a raising scenario:
Step-by-Step Guide: Twin Tension Knot Pass During Raising
Step 1: Position the Knot and Prepare the Prusik Transfer
Begin by raising the load until the Prusik hitch and knot on the primary line sit approximately 1.5 meters below the Clutch. This gives you enough vertical space to work without crowding the device.
Shift your focus to the alternate rope, which will temporarily carry the load. Reset the Prusik hitch on this rope to prepare for the transition. This ensures you can safely offload tension from the primary rope while maintaining continuous system integrity.
Step 2: Build a Temporary Anchor for Load Holding
On the primary rope (the one with the knot), pull slack from the mechanical advantage system and tie a secure figure-eight loop. Clip this loop into a strong, redundant anchor.
This step effectively creates a mid-system directional anchor that allows the system to maintain control of the load independently from the Clutch. It acts as a temporary holding point while you reposition the main rope.
Step 3: Transfer the Load and Re-rig
With the Prusik holding on the alternate rope and your figure-eight loop anchoring the primary, continue hauling on the alternate rope to introduce slack in the line with the knot.
Once the primary line is completely unweighted:
- Remove the rope from the Clutch.
- Reroute it so that the knot now sits above the device.
This rerouting ensures the knot does not interfere with the device or disrupt the raise. It clears the operational path while maintaining dual-rope redundancy.
After rerigging, untie and remove the figure-eight loop to free the rope from its temporary anchor.
Step 4: Reconfigure the System and Resume Raising
Remove the Prusik hitch from the alternate rope—it has served its purpose. Now, build a new 3:1 mechanical advantage system below the Clutch, reattaching the load-lifting mechanism in a clean, properly balanced configuration.
Begin the raise again, with the knot safely positioned above the device and the load evenly distributed across both ropes. Confirm equal tension, monitor pulley alignment, and check friction points before proceeding with full operational load.
Operational Benefits of Twin Tension Knot Pass in Raising Systems
Efficiency
- This method allows the team to pass knots without deconstructing or resetting the entire rigging system.
- Raising operations remain smooth and uninterrupted, ideal for complex rescues requiring time-sensitive performance.
Safety
- The TTS provides full redundancy, reducing single-point failure risk.
- Load is never completely disconnected from control devices, ensuring the system remains safe under high tension.
Versatility
- Compatible with Clutch, MPD, and other MA devices.
- Adaptable to a wide range of terrains, team sizes, and operational setups.
Final Notes
The Twin Tension System knot pass method stands out as a technically advanced yet highly practical solution for field operations. It is especially valuable in missions where the integrity of every transition must be maintained and where missteps could compromise load safety.
For rope rescue technicians operating at the NFPA 1006 level, this technique reinforces mission-critical principles: maintain control, minimize downtime, and manage complexity with clarity.
When properly trained and implemented, the TTS knot pass can become a cornerstone technique in any serious rope rescue team’s toolkit.
Peace on your Days
Lance
