To facilitate horizontal or diagonal movement across an open space on a rope system, ropes can be tensioned between two sets of anchors. For a horizontal tensioned line, you'd rig the control ropes below the tensioned ropes. For an angled tensioned line, additional working and safety lines will be needed to give you enough control of the load.

An important goal when rigging a tensioned line, is to rig it so that the load is evenly shared between both anchor points and ropes (using only as much tension as is needed for the system to work). Uneven loading will cause unnecessary wear and stress to one element of your equipment. Use your knowledge of angle physics (refer to Annex 4 in SPRAT's Evaluation Guidelines) to protect the longevity of your equipment and to make the system easier and safer to utilize. 

During your SPRAT Evaluation, L3 techs will be asked to demonstrate competence transporting a load along a horizontal or angled tensioned rope system, while maintaining as little tension as is practical.

Over-tensioning a system minimizes the amount of energy absorption in the rope by using up the stretch potential before a load is even applied. While this may reduce the sag in the system, this leads to a higher angle across the span of the line. The higher this angle, the higher the load on the anchor system becomes.  If you can't get high enough without cranking your line up to 150 degrees, we recommend that you consider another method.

On Evaluation Day, your SPRAT Evaluator will specifically be watching to make sure that you...

• Can estimate the forces a horizontal and angled tension line will place on the system, as well as the point where the highest forces are experienced by the anchorage system.  
• Minimize the length of back-up lanyards (the smaller their length, the shorter the fall distance -- minimizing the dynamic impact load that would result from equipment failure).
• Connect the load to the tensioned rope(s) using 2 connection points. 
• Control movement -- specifically if using an angled tensioned line.
• Consider a rescue plan (using releasable rigging at one or both ends of the tensioned lines is one option, which you’ll be encouraged to consider).

There are some angle physics laws you can rely on when calculating where the highest forces will occur in a tensioned line. In a horizontal tensioned rope system, that highest force will occur when the load is halfway between both anchors, where the control ropes are slack. In an angled tensioned rope system, the highest force will occur as the load approaches, but is still above, the lower anchorage system -- this is the point where the tensioned ropes begin supporting a higher percentage of the weight of the load than the upper control ropes. 

You may be asked to demonstrate this requirement on your own or with a team. You might also be able to demonstrate a tensioned rope system as part of the L3 team scenario. Your options here will be largely up to your SPRAT Evaluator's discretion.

Most Common Discrepancies to Avoid: