Petzl Rad System

The REVERSO is designed for use on single ropes greater than 8.9 mm in diameter, and on half or twin ropes greater than 7.5 mm in diameter.

With the 6 mm RAD LINE cord, the braking capability of the REVERSO is insufficient.

While rappelling, if the user needs to negotiate tricky sections, free a hand and/or untangle the rope, there is a risk of losing control of the rappel.

Even so, there is a way to use the REVERSO with the RAD LINE cord: set up your REVERSO with two braking carabiners.

The advantage of the REVERSO is its simplicity of use, especially for a beginner with poor Munter hitch skills. It also twists the rope less than the Munter hitch.

In any case, using a rappel backup system is recommended.

RAPPEL BRAKING TESTS

Test descents done on a "free hanging" 10 meter rappel.

Rad Line Joining Knots

Tests of joining knots useful for rappelling and glacier travel with RAD LINE cord.

1. Rappelling On RAD LINE: Recommended Knot For Joining Two Strands

The tests show that knots which are carefully tied and tightened before use provide enough strength for normal rappelling forces. The primary question isn't about the strength of the knot, but of its resistance to capsizing. Capsizing "consumes" the tails, so the best precaution - regardless of the knot used - is to leave long enough tails (30 cm minimum).

Notes:

• The knot was not tested when jammed against a rappel ring
• The knot was not tested for joining two ropes of different diameters
• Testing was done only on RAD LINE cord

WARNING: Figure 8 knot behavior can vary significantly depending on whether it is correctly or poorly tied, correctly or poorly tightened. It is also often difficult to untie after use. This is why the flat overhand bend seems more reassuring for this application.

The double fisherman's knot, strong and reliable but also difficult to untie, is known to get stuck easily when retrieving the rope.

2. Roped Progression With RAD LINE: Recommended Knot For Joining Two Strands

The tests show that the force of a fall can be enough to capsize a poorly-tightened figure 8 knot or cause a flat overhand bend to slip. So it is essential to carefully tie and tighten the knot and to leave long enough tails (30 cm minimum).

But in a glacier travel situation, we also know that a bulky knot is an advantage in helping stop a fall (the knot can jam against the crevasse lip).

Tying a stopper knot in the tails thus seems very appropriate:

• The recommended 30 cm minimum tails are long enough to tie a stopper knot
• The knot's bulk is an inherent advantage in a fall

3. Note On Tightening The Knot

In this study, a knot is considered "well tightened" if the 4 strands have been individually tightened. Simply pulling on the two strands together on each side of the knot is insufficient.

4. Test Results

WARNING: The data presented are valid only for RAD LINE. They could be very different with a cord of different diameter or material, especially in the case of a cord with a slippery Dyneema sheath, or any joining of ropes or cords of different diameters.

4.1. PULL TEST, TWO STRANDS OF RAD LINE TIED TOGETHER

	Figure 8 knot correctly tied and tightened: First capsize between 5 and 7 kN. Further capsizing between 5 and 7 kN. Rope released after successive capsizing consumed all of the tails. (Each capsize consumes 2-3 cm of tail.)   Figure 8 correctly tied but poorly tightened: First capsize between 1.2 and 2.6 kN. Further capsizing between 5 and 7 kN. Rope released after successive capsizing consumed all of the tails.
	Flat overhand bend correctly tied and tightened: First capsize between 4 and 5 kN. Further capsizing between 2 and 3 kN. Rope released after successive capsizing consumed all of the tails. (The first capsize consumed 2-3 cm of tail, further capsizing consumed about 1 cm of tail but at lower forces).   Flat overhand bend correctly tied but poorly tightened: First capsize between 3.5 and 5 kN. Further capsizing between 2 and 3 kN. Rope released after successive capsizing consumed all of the tails.
	Double fisherman's knot: Cord breaks at 9 kN. No capsizing before failure.

4.2. FALL ARREST TEST: TWO STRANDS OF RAD LINE JOINED TOGETHER

The pull tests were supplemented by fall arrest tests.

For repeatability, tests were done in a lab: arresting an 80 kg rigid mass falling 35 cm. A real fall into a crevasse would no doubt be longer, but many variables can reduce the impact force: rope friction on the crevasse lip, belayer displacement, harness deformation, knot tightening, energy absorption by the body... In comparison with forces measured in the field, we see that the laboratory impact force values, with a rigid mass, are slightly greater than in reality.

	Figure 8 knot correctly tied and tightened: Force measured at the anchor: greater than 5 kN. Very little rope slippage in the knot.   Figure 8 correctly tied but poorly tightened: First capsize at less than 2 kN, then the knot tightens and stops the fall with a force close to 5 kN: danger if the tails are too short!
	Flat overhand bend correctly tied and tightened: Force measured at the anchor: between 3 and 4 kN. More than 10 cm of tail slippage in the knot: danger if the tails are too short!   Flat overhand bend correctly tied but poorly tightened: Behaviour very similar to a correctly tightened knot: danger if the tails are too short!
	Flat overhand bend with stopper knot: Force measured at the anchor: between 4 and 4.5 kN. Slippage in the first knot is stopped by the second knot, which does not slip at all; this is the most reassuring configuration in our tests.

What is the Rad System Used For?

Kit with thin hyperstatic cord for rappelling, crevasse rescue and roped glacier travel.

The RAD SYSTEM can be carried when the anticipated situation does not require the use of a dynamic rope.

Its light weight and small size allow this minimal kit to be carried on trips of low technical difficulty, offering a means of protection in escape situations, or when negotiating obstacles on the descent.

---

---

Other Progression Situations That Are Incompatible with the Rad line Hyperstatic Cord

Any progression situation that uses anchors with the RAD LINE presents a danger to the user in case of a fall.

Short Roping The goal of this technique is not to arrest a fall, but to minimize the chance of a fall through the constant vigilance of the leader. There is thus no limitation with the RAD LINE cord, provided that the belay method doesn't change along the way, for example by using anchor points to cross a steep section. Note: Most of the tests done with this technique demonstrated a high probability of a group fall regardless of the rope used. This technique is reserved for use by experienced and knowledgeable leaders.

Who Carries The Rope in a Group of Skiers?

When traveling unroped, the rope must be ready to be effectively deployed in case of an accident. Without going to the point of pre-installing a haul system in a pack, and without overloading the skiers with excessive equipment, it is necessary to anticipate the risks that will be encountered on the planned route, in order to distribute the equipment in a logical manner.

Attention: We are talking only about collective or rescue equipment; each user must choose his/her personal equipment according to the situation.

1. Skiing On A Glacier With A Clear Leader

The leader goes in front to find the route, and so is the one most likely to fall into a crevasse, and therefore must not be the only one carrying a rope.

On a snow-covered glacier, all group members are susceptible to being surprised by a hidden hazard. So you must maximise the chances of rescue by having at least two ropes in the group, carried by teammates sufficiently separated from one another.

Note: The decision whether to ski roped or unroped on a glacier cannot be taken except on-site, depending on the conditions and assessed risks. This is not the subject of this advice, which only addresses the case where the choice is made to ski unroped.

2. Couloir Or Descent Which Is Certain To Not Have A Steep Section Over 15m In Height

Except for specific cases (route finding, uncertain conditions), the most skilled skier goes second and carries the rope. He/she can help the first skier from above in case of a problem.

Otherwise, if the first skier takes the rope down a steep section which the second skier cannot negotiate, the first skier cannot help the second.

3. Couloir Or Descent With A Planned Rappel Of More Than 15m Or With Uncertainty About The Possible Obstacles.

To share the weight and bulk, each teammate carries a RAD SYSTEM. The equipment in the kit allows a rappel to be improvised in many situations. Depending on the case, it may be complemented with rope slings or pitons to create improvised anchors.

Helping a Partner During a Ski Descent

The second skier carries rope and equipment to create an anchor and belay, to be able to help the first skier in case of difficulty.

Belaying Off a Snow Anchor

If no natural anchor is available (rock horn, tree...), create a deadman with your ice axe. After tethering yourself, you can throw the rope with an attached carabiner so that the first skier can easily attach him/herself.

Do not belay directly off an anchor of questionable strength.

The belayer is tethered to the anchor, keeping the tether taut to reduce the chance of shock loading (consider the CONNECT ADJUST for this usage). The belayer takes a braced stance, possibly on a platform dug in the snow, and belays off the harness. Belaying is done with a Munter hitch as it offers adequate friction in any position. Warning: do not belay off the harness using a REVERSO, without a redirect: the rope and hand positions do not allow for adequate braking.

Belaying Off a Natural Anchor

If a solid natural anchor is available, the operation may go faster. The anchor can be used to redirect the rope, making for a more comfortable belay position and enabling use of the REVERSO.

Movement of the Second

On a fixed natural anchor, the second can set up a rappel to descend the difficult section. Otherwise, s/he should downclimb.

What Should I Do If My Rad Line Cord Has Sheath Slippage?

Your RAD LINE cord has sheath slippage and you still want to use it... Follow the steps below to extend the life of your RAD LINE.

Start by doing a full inspection of your RAD LINE with the help of our PPE inspection form.

If your RAD LINE inspection results are satisfactory and the damage is limited to a small area near the end(s) (fuzzy or soft spots, swelling, cuts, sheath slippage...), you can extend your RAD LINE's life by cutting off the ends.

You will need adhesive tape (strapping tape or duct tape) a SPATHA and a lighter.

1. Cut the cord in the damaged area to free the sheath from the core.

2. Pull on the sheath.

3. Locate the area where the core is present.

4. Use tape to mark the place to be cut, at least 5 cm from the damaged area.

5. Wrap a piece of tape tightly around your RAD LINE, cut and singe the new end of the RAD LINE to prevent fraying.

Attention: If you do this operation multiple times or if you cut off a long piece, your RAD LINE will be shorter than its initial length and the middle mark will no longer be accurate.

Check the accuracy of the middle mark by following the procedure below.

Case 1 - The difference in length between the strands is less than 60 cm: your rope still meets the UIAA standard requirement for a middle mark.

Case 2 - The difference in length between the strands is more than 60 cm: trim the longer side of your RAD LINE before marking the new RAD LINE length on one end.