One of the challenges rescuers may face when performing high-angle rescues involves controlling the position of the victim in more directions than simply up and down.
Any environment that presents a cliff or wall face with obstacles or outcroppings will require multidimensional control. This leaves rescuers with three basic choices: tending, tensioning tag lines or tensioning track lines. Be sure to watch the demonstration video at the end of this article.
Tending is when a rescuer progresses up or down with the victim and physically controls their position. This is the simplest rigging solution and usually requires only Level I skills.
There are many different ways to rig for this; the most common involves attaching a pick-off strap or small system such as a CMC Aztec between the master attachment point and the rescuer.
Belay attachments have many different configurations as well, but usually involve a midline knot attached to the master attachment point and the tail of the belay attached to the victim in the stokes basket or packaging device. Rescuers extend or collapse their system or pick-off strap to position themselves on the basket so that they can maintain foot contact on the wall or cliff face and use good body mechanics to pull out on the victim and work around obstacles.
Tensioning tag lines
Tensioning tag lines involves attaching rope(s) to the master attachment point or to the ends of the packaging device and pulling tension or giving slack to pull the victim away from the wall or allow them to get closer to the wall.
These ropes can be managed manually without a progress-capture or safety device in place, but the risk increases dramatically. If these ropes are not run through a safety device or paired prussiks to capture progress, the victim could careen dangerously into the wall or cliff face.
This is an additional challenge because a device needs to be selected that seamlessly transitions between hauling and lowering applications to manage the victim position. Traditional rigging such as an RPH would not be practical because of the time delays in transferring the load between operational modes.
The greatest danger with tensioning tag lines is the potential to overload the entire system. Tensioning tag lines result in oppositional forces to the top-side hauling system and multiplication forces during lowering operations. The lower/haul operation and the tensioning tag line operation have to be very closely coordinated to avoid system overloading.
Tensioning track lines
Tensioning track lines involves building a standard lower haul system and then building track line(s) with variable tension control. We then attach a pulley to the master attachment point, which is placed on the track line(s).
When track lines are used in this application, they are commonly referred to as guiding lines. Without delving into all of the advanced physics, there are some basic approaches that will keep you safe.
Use twin track lines. This is not always a necessity depending on load and angle or amount of tension applied to the track lines. However, a single track line does not afford any redundancy and can be easily overloaded when approaching critical angles.
In this application, alter the tension on the track lines as needed. This means the track lines will tension and slack as needed to pull the load away from the wall or cliff face but maintain as little tension as possible throughout the operation.
This approach greatly reduces much of the overload factor of track lines at critical angles, but using twins will always keep you safer.
High-strength tie offs
Apply high-strength tie offs or tensionless wraps to one end of the track lines and a 2-to-1 system in a series on the other end with a versatile progress-capture device such as a CMC MPD. Which end of the track lines serves what purpose is highly dependent on the environment and the choice of high directional at the top side.
There are other mechanical-advantage systems that can be used, but attaching two 2-to-1 systems that are in a series to each of the track lines will give the haul team adequate mechanical advantage to tension the track lines when needed but avoid having excessive mechanical advantage at their disposal, which could possibly overload the track lines.
I advocate the MPD because of its versatility for transitioning between tension and slack operations as well as the smooth cam, which provides good capture without the sheath penetration of a toothed-cam device.
Other devices can be used in this application provided they have appropriate design load and operational transitions that are seamless and simple. Attaching the 2-to-1 in a series system to the track lines is another option.
I encourage rescuers to apply 9-mm prussiks to their ½-inch rope to increase the strength and slip factor of the prussiks. The track lines cannot be anchored effectively because the track lines are moving constantly in this application so the increased safety of upgrading prussik diameter may pay dividends.
Tension when necessary
If an out cropping is present towards the top side, a margin of tension on the track lines may be required throughout the lift to avoid friction contact between the lower haul lines and the outcropping.
The other option is to place positional edge protection at the outcropping and then only apply tension when the load or victim package needs to clear the obstacle.
Both are viable options, but keep the load and ropes as close to the wall or cliff face as possible. This provides two margins of increased safety.
If the track lines were to fail, the impact of the load against the cliff face or wall will be greatly reduced by minimizing the distance of the pendulum arc. The second safety benefit is the reduction of force on the track lines. Keeping the tension at a minimum will help ensure safe forces on the track lines and eliminate overloading or critical angles.
To bring it all together, a good rescue team will have all of these approaches in their arsenal. Knowing the pros and cons of each application will help you make the right decision.
Remember to let the victim drive the rescue as well as the safety of your team. Train hard and continue to hone your knowledge, skills and abilities.
