Double CLUTCH | Using the CLUTCH In a Twin Tension Rope System (TTRS)

Written By: Lance Piatt

I always appreciate great video.  Video (to me) is either aesthetic or technical and trying to bridge both is tough. This video from CMC is clearly technical, but I really appreciate the angles of perspective. So often the “clarifying message” of “the how” can get completely lost if the angles are not right. The CMC Clutch by Harken Industrial is a “dream come true”.

Thanks CMC for making this demonstration of  CMC-Harken Clutch very straightforward.

Welcome to the Clutch application video series. For this video we’ll focus on the Clutch being used in a twin tension rope system or TTRS. We will not focus on the technicalities anchoring these systems. Refer to your department policy and anchoring guidelines for your preferred anchor rigging. A twin tension rope system is the current best practice for rigging, raising and lowering operations in rescue scenarios. Rigging TTRS can vary based on location, equipment and human resources available for the operation. This video will review a progression of four TTRS scenarios and the risk or challenges associated with each.

In this first rigging scenario, we have the Clutch rigged to two individual anchors with two operators, each operating the Clutch handle and rope tail. As the load which includes a rescuer and the occupied litter approached the edge, the load that the Clutch seized is relatively light through the absence of gravity at this stage of the lower i.e. the edge transition. As soon as the litter is over the edge, the operators move from one slack and one tension line to a shared tension system where the load is evenly divided between the two devices. Any catastrophic event to one of the lines will shift it slow to the alternate tension line, thereby reducing the shock and extension on the line compared to an unintentioned belay system. The challenge in this scenario comes from coordinating the lower between the two operators. Regardless of proximity of the two individual lines, both operators may find it challenging to balance the load equally depending on training and experience.


In scenario two, if additional rescuers are available, the team can reduce the risk profile by adding an additional tailor to the lowering system. In this case, a single rescuer can manage both tails from each Clutch device and serve as backup to the Clutch handle operator. Tail can be redirected to a center location. If the operator experiences issues with controlling the speed of the lower, the tailor serves as risk mitigator in the operation. The tailor can stop the lower by holding firm on both rope tails.

In this third rigging scenario the number of rescuers is limited. If anchoring is appropriate and gear is available, the Double Clutch TTRS can be used to replace people with gear. Clutch units are rigged so they can be controlled by a single operator. We call this a Double Clutch. A backup device and shock absorber designed for a two person load is connected via carabiner to each clutch bucket and installed on the tension side of the clutch. One operator controls both Clutch handles and both rope tails. The backup device serves as an unattended blade device i.e. A backup tailor. There could be circumstances and less than vertical operations when the operator fails to control the speed of the lower yet the backup devices have not reached trigger velocity.

Scenario four provides a solution for mitigating the risk of an uncontrolled lower by rigging the Double Clutch with a single operator to manage the handles and tails and a second rescuer as backup tailor to monitor the system with both rope tails in hand. Because each person is able to see and feel the ropes in service, this rigging scenario also promotes better shared tension at each clutch. In all cases, a confident and properly trained operator is the best defense against some uncontrolled lower. A twin tension rope system is the current best practice for raising and lowering in a rescue situation. This video demonstrates four rigging scenarios for using the clutch and TTRS depending on location, equipment and human resources. Each scenario comes with different risks and training requirements and selecting the right system depends on your particular rescue or training operation.

Buy Now!

CMC Clutch 
Petzl ASAP Lock
CMC Stainless Steel Rescue Litter
CMC G11 Lifeline
CMC Double Clutch TTRS Kit


For more information on the Clutch, visit for additional video and technical content.

Peace on your Days



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  • Great content! Super high-quality! Keep it up! 🙂

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