STRETCHER LOWERING AND RAISING TECHNIQUES

Transcription

1 Chapter 6 STRETCHER LOWERING AND RAISING TECHNIQUES Acknowledgement: In May 2000, the RAF MRS adopted a new system of technical rescue based largely on techniques developed and presented by Rigging for Rescue of British Columbia, Canada. Much of the technical data and a number of illustrations in this chapter have been reproduced with kind permission from Rigging for Rescue and the Technical Rescue Riggers Guide by Rick Lipke. Team Practice Carrying out a casualty evacuation on a steep mountainside or cliff calls for a high degree of teamwork and skill from rescuers if the operation is to be completed safely and efficiently. It is therefore essential that MRTs practice in the skills of steep ground rescue on a regular basis. A convenient road-side crag may be useful for training; however experience should be gained on a variety of terrain and in all conditions, summer and winter. Even for experienced teams, broken faces are more difficult and often more hazardous than the smooth vertical ones which look so impressive. All MRS personnel involved in steep ground rescues should be confident to operate effectively in the environment and, once trained, must be fully competent in stretcher preparation, construction of anchor systems, belaying and abseiling. Knowledge of a number of systems and techniques and how to correctly and rapidly implement them is important, as is the selection of anchors and equipment required. Team members will receive sufficient training in stretcher lowering and raising techniques to enable everyone to take an active part and gain an understanding of the difficulties involved. An Introduction to Systems Analysis and the Rescue Load Put simply, systems analysis is the process by which we decide whether a particular rope rescue system is safe to use. By conducting a few simple calculations and applying a number of what if? questions, we can calculate the strength of the system and its component parts. By this process we can identify the weakest link in the chain and can also determine the system s ability to withstand a dynamic event or shock load, as might be caused by equipment failure or operator error. The SI System of Units Before we can begin to make useful calculations relating to rope rescue systems, it is first necessary to gain an understanding of the terms and units of measurement used in systems analysis. These units are universally known as SI Units, of which the ones most commonly used are: Base Units: Length = metres (m) Time = seconds(s) Mass = kilograms (kg) Derived Units: Velocity [the distance (m) an object moves over a period of time (s)]: = m/s Acceleration [the change in velocity (m/s) of an object over a period of time (s)]: = m/s/s = m/s2 6-1

2 Acceleration due to Gravity (a constant rate of acceleration caused by the Earth s gravitational pull) = 9.81m/s2 (rounded up to 10m/s2 to ease calculations) Force: Force is simply defined as: a push or a pull In other words, it is the influence which when applied to an object causes it to accelerate. For example, gravity places a force on objects, causing them (or giving them the potential) to accelerate at 9.81m/s2. For ease of calculation (i.e. an error of less than 2%) this number is rounded up to 10. The unit of force is the newton (N) or kilonewton (kn or 1000 N). One newton will give a mass of 1 kg an acceleration of 1m/s2. This can most easily be shown as: Force (N) = mass (kg) x acceleration (m/s2) or more simply; F = ma For example, to calculate the force or tension acting upon a rope by a free hanging 100kg mass: F = 100kg x 10m/s2 (due to gravity) = 1000kg m/s2 = 1000 Newtons = 1kN We must now consider the likely loads that we might be required to raise or lower: The Rescue Load Based on UIAA testing parameters where the mass of an average climber is deemed to be 80kg, a standard 2-person (1 guide + 1 casualty) rescue load will consist of 2 x 80kg plus 40kg for stretcher and equipment, totalling a mass of 200kg. For a 3 person (2 guides + 1 casualty) rescue load, this figure is increased to 280kg, as shown in the table below. Note that a free hanging 200kg mass exerts approximately 2kN of tension/force on a rope. Rescue load size Mass in kg Force in N Force in kn 1 person guide 1 cas. + stretcher 2 guides 1 cas. + stretcher = = A rescue load of 200kg mass will create a Peak Force of 10-12kN during a 1m fall factor 0.3 drop on 11mm LSK when belayed with a Tandem Prussic Belay 6-2

3 Systems Analysis STRETCHER LOWERING AND RAISING TECHNIQUES To pass a full systems analysis the system must meet certain minimum criteria; these are as follows: Static System Safety Factor (SSSF): To achieve the desired dynamic safety ratio when building a rescue system, we should ensure that the strength of the system and its component parts is at least 10 times greater than the force applied by the static rescue load. As an example, for a 2 person rescue load (2kN), each component part must have a minimum strength of 10 x 2kN = 20kN, if we are to achieve a 10:1 SSSF. By adopting a Static safety factor of 10:1 we achieve a 1.5-2:1 Dynamic safety factor, ensuring that the materials used in the system are not loaded past their yield point. Whistle or Hold Up Test: To pass this test, the system must include a hands-free means of catching a falling rescue load that is not dependent on the actions of the Main or Safety line operator. Critical Point Examination: The critical point examination involves ensuring that all points are backed up by other system components in such a way that no one point (either equipment or personnel) would cause a serious or fatal accident were it to fail. One exception is the 12mm single maillon which, with a breaking strength of 87.5kN is sufficiently strong to allow it to be discounted as a Critical Point. To allow rapid analysis it is necessary to know the breaking strength of key items of equipment. Most metal items have the breaking strength marked on them. Some items such as maillons are marked with their Safe Working Load (SWL) rather than breaking strength. In this case the breaking strength is 5 times the SWL. Typical breaking strengths of tubular nylon tape and low-stretch ropes of varying diameters is shown under Technical Rescue Ropes. Technical Rescue Ropes It may be possible, of course, to carry a loaded stretcher away from the scene of an accident with no more difficulty than you might expect walking over rough ground, heavily laden. Sometimes, however, the casualty must be recovered from a cliff or steep-sided gorge and it will be necessary to raise or lower the stretcher using ropes. Whereas in climbing we require the rope to stretch to absorb the potential impact force of a falling leader, in rescue work, where loads are much greater but the likelihood of shock loads much less, we require ropes with only limited stretch. Indeed, climbing ropes are, except in cases of genuine emergency, unsuitable for raising or lowering the stretcher, due to their elongation under load. For this reason RAF MRTs use 11mm Low-Stretch Kernmantle (LSK) ropes with an average un-knotted breaking strength of 33.5kN and an elongation of less than 4% (measured with a 150kg load applied) for all stretcher work. Two ropes are used for the majority of the techniques described in this chapter; the Main line is the primary working rope used for both lowers and raises, while the Safety line provides an essential backup, as will be described later. 6-3

4 Because of their lower elongation properties, resulting in shorter stopping distances and increased Peak Force values when compared to ropes designed specifically for climbing, LSK ropes must never be used for that purpose. Of equal importance is the fact that all ropes should be protected from abrasion or cutting when passing over cliff edges or sharp rocks and that any situation where a moving rope might come into contact with a static rope is avoided. LSK ropes should be soaked and slowly dried before first use to shrink the mantle onto the kern and so avoid potential sheath slippage. Typical breaking strengths of LSK ropes of various diameters and of 25mm tubular nylon webbing are shown in the following table: Rope Diameter (mm) Typical Breaking Strength (kn) mm Radium 30+ Release Hitch Spectra 22 Dyneema sewn sling 25mm tubular webbing 18 (open ended) Note that knots in rope or tape can reduce the breaking strength by up to 39%, however, for all practical applications and calculations a loss of 33% or 1/3 may be used. The following table gives the typical loss of breaking strength for some commonly used knots when tied in LSK or tape: Potential loss Knot type in un-knotted breaking strength Fig 8 on a Bight 33% Alpine Butterfly 38% Overhand on a Bight 39% Bowline 37% Double Fisherman s 30% Knots in tape: Tape knot 36% *(based on HSE tests) ** (based on CMC tests) Edge Protection During any operation involving ropes under tension, the contact between the rope and the cliff edge is a critical factor. Care must be taken to use adequate protection where the ropes pass over such edges, or any other sharp rocks, which could cause damage or failure. Nylon edge protectors, as shown in Fig 6.1 have an additional advantage in that by reducing friction, they increase the efficiency of any raise. 6-4

5 Fig 6.1: Edge protection in use 6-5

6 Types of Lower / Raise A number of techniques are covered in this chapter including Vertical and Horizontal Lowers, Vertical Raise and the Kootenay Highline System, which has replaced the Tension Lower and Gorge Liftout. Two Pick-offs, for situations where a stretcher is not required, are also included. An understanding of these systems should enable team members to extract a casualty from any predicament. However, only the basic methods are covered in detail, and it should be remembered that no two situations are the same. A combination of the various techniques may be required to facilitate an efficient and successful rescue while certain situations will call for a specific rescue technique. For example, where a casualty is located on a cliff with many unstable rocks above and below, the preferred method for extrication would be by Highline or Guiding line whereas if speed of evacuation is vital, the fastest method is often by means of a Vertical lower or Pick-off. A casualty suffering from shock or with spinal injuries should not normally be placed in a vertical position and will therefore require a Horizontal lower or raise to prevent possible further injury or a worsening of their condition. System Components Many of the component parts of different technical rescue systems are shared. These include the use of a Main and a Safety line as mentioned previously and the use of Tandem prussics to catch a falling rescue load (and which allow our systems to pass the Whistle Test). Prussic Minding Pulleys, the Load or Radium Release Hitch (LRH/RRH) and finally the brake rack, used to control lowers, are also included and each is described below. Additional anchor system components such as front and back pretension ties and the use of high-strength tie-offs are described later. Main Line: For many of the techniques a single 11mm LSK rope is used as the primary lowering / raising rope, the exceptions being the 2-guide Horizontal lower and some Highlines/Gorge Lift outs. Safety Line: The Safety line, which is also a single un-tensioned 11mm LSK rope, provides an essential backup should the Main line fail for any reason. It is anchored separately via Tandem prussics and a RRH. Alternatively a 540o Rescue Belay device may be used in lieu of the Tandem prussics and RRH. Tandem Prussics: Tandem prusiks of unequal length are attached to the Safety line and clipped into the same karabiner, generally with a RRH between the prusiks and the anchor. Tied and operated correctly, the Tandem prusiks act as a hands-free autobloc that will catch a falling rescue load should the need arise. When used with 11mm diameter Safety line, 8mm prusiks should be used, made from a 3m length of LSK, cut into 1.65m and 1.35m lengths to give one long and one short prusik loop. A single 8mm LSK 3-wrap prusik is suitable for Main line pulley autoblocs that would not be required to catch a falling rescue load and for connecting a tensioning system to the Main line. LSK cord that is either excessively stiff or soft should be avoided when making prussic loops, as performance may be adversely affected. A simple test is to use the pinch test, shown in Fig 6.2. The ideal gap between the folded cord is approximately4mm, or 1/2 its diameter. Two prusiks are used where shock-loading is a possibility, such as on the Safety line, and are also desirable in high load situations such as on Highlines, as there is essentially twice as much nylon to melt to absorb the energy of such a shock. Although the two prusiks are designed to work simultaneously under a shock load situation, they do not share the work equally and it will often be the case that the shorter prusik effectively catches the load before the longer prussic comes in to play. 6-6

7 Fig 6.2: Prusik cord pinch test Three-wrap classic prusik knots are used and it is important that the knots are tied neatly and correctly. They must be well seated before use (tight enough for the belayer to hear the friction of the rope being pulled through, but not so tight that he cannot slide the rope). The prusiks should be rigged so that, when they are stretched away from the anchor, there is a gap of about 10cm between them (use the width of a hand as a guide), although they are pushed together for ease of use in most operations. When lowering a load, the belayer prevents the prusiks inadvertently locking by minding them and pulls the rope through the prusiks, while keeping them snug enough to react properly to a fall. Should this occur, friction between the suddenly moving ropes and the prusiks causes them to tighten and grab the rope. Tandem prusiks typically settle into the rope within 5cm of their original positions, laying a mild glaze on its sheath from there on if they slip. Fig 6.3 shows the Tandem prusiks set up for a lower. Fig 6.3: Tandem Prusiks - lower (RRH shown loosely tied for clarity) 6-7

8 The following are general rules for belayers when operating Tandem prusiks: Always have an attentive belayer; do not leave the belay system unattended. Ensure that the Tandem prusiks are both correctly tied and set on the parent rope. Do not wrap thumbs around the Safety line when operating a Tandem prusik belay; use a hitch-hikers grip instead, with a twist of the hand, giving no more than approx. 25cm of slack in the Safety line, as shown in Fig 6.4. Always have an extra RRH and a set of Tandem prusiks standing by for knot passing (described later). During a fall or system failure, quickly push the Tandem prusiks in the direction of the force. Aggressive belay operation may be necessary in extremely wet, muddy or icy conditions. Fig 6.4: Tandem Prusiks - Hitch-hiker s grip for lowering Prusik Minding Pulley: The unique shape of the Prusik Minding Pulley (PMP) has been specifically developed to allow the efficient use of both Single and Tandem prusik knots as autoblocs for use during raises. It has a high breaking strength and a large pulley wheel to give maximum efficiency. To prevent the prusik from binding, it is important that a finger-width gap is left between the pulley and the first wrap of the prusik, as shown in Fig 6.5. A PMP also makes it easier to take in the Safety line when a load is being raised. 6-8

9 Fig 6.5: Prusik Minding Pulley with Tandem Prusiks (RRH shown loosely tied for clarity) Load Release Hitch: The Load Release Hitch (LRH) has several applications in rescue work including passing knots, making changeovers from lowers to raises and generally as a means to release the tension in things like locked up belay devices. It is particularly important when using Tandem prusiks as it has the ability to release tension after enduring a rescue-sized shock force, such as when the prusiks have arrested a falling load, (eg during a Main line failure) or an accidental lock-up. The LRH can be extended with control, and in so doing, transferring the load from the prusiks back to the Main line, allowing the lower or raise to continue. (Note that in a raise it is not normally necessary to release the LRH; simply continue the raise until the Safety line becomes slack again). The Radium Release Hitch (RRH) is an improved LRH, developed by Rigging for Rescueâ and adopted by the RAF MRS. It is constructed using 10m of 8mm LSK and 2 HMS / pearshaped screwgate karabiners. It is tied as follows. (See Fig 6.6): 1. Tie a Figure of 8 on a Bight and clip it into the load-side karabiner on its spine side. 2. Clip the standing part of the cord up through the anchor karabiner, back down through the load karabiner; bring it back up to the anchor and tie an Italian Hitch onto that anchor karabiner on its gate side. Ensure that the Italian Hitch is in the release position with the in-feed rope towards the gate side of the karabiner. A reasonable length for the completed hitch is 10 to 15cm. 6-9

10 3. Secure the RRH using a bight to tie a small loop, big loop lock off around the entire stem below the Italian Hitch, and then back it up with a Half Hitch; again around the entire stem. 4. Tie a Figure 8 on a Bight at the other end and clip it to a secure anchor if desired. (diagrams are shown tied loosely for clarity) Fig 6.6: Radium Release Hitch The Brake Rack: The brake rack is used to provide primary control of the stretcher during lowers and is attached to the Main line. It has the advantage over Figure of 8 descenders for lowering rescue loads in that it provides variable friction and does not twist the rope. Lowerers should face the brake rack during operation and should be positioned at the load end of the rack, not at the anchor end. A minimum of 4 bars should be used for rescue loads, with further wraps being taken around the pronged hyperbars and the bars cinched together as shown in Fig 6.7 to give additional friction. Care must be taken to ensure that the rope is correctly routed through the device and a functional test carried out before every use. The rack must be locked off if it is to be left unattended. The brake rack is locked off by taking 2 turns around the hyperbars as shown in Fig 6.8 a-f, followed by a small loop - big loop tied around the frame of the rack to finish. A further Half-Hitch should be added if the rack is to be left unattended for any reason. Where 2 Main lines are used, as with a 2 guide Horizontal lower, they are both controlled by a single brake rack, but are locked off independently, on either side of the device. Have a RRH and prusik handy in case you need to pass a knot in the rope (described later). 6-10

11 Fig 6.7: Brake Rack Operation 6-11

12 Anchor Systems for Rescue Work Fig 6.8: Brake Rack lock-off (single rope) a-f Ropes and anchor systems used for stretcher work may be subjected to much greater forces than thosefound in a normal climbing situation; when there is seldom more than the weight of one person on the rope at any one time. In addition, rope rescue systems may be subjected to even greater loads by the application of tension using pulleys. It is therefore essential when working with rescue loads that good, strong anchor systems are constructed before attempting to lower or raise. All anchor systems should meet the 10:1 Static System Safety Factor requirements; however, this can be difficult to establish when selecting anchors consisting of natural objects such as trees and boulders. Judgement based on knowledge and experience must be applied here. 6-12

13 Although a reliable anchor system is always selected for an exercise, there may not always be one available on a real rescue. Practice should therefore be carried out in the art of lowering smoothly, without shock-loading the system, and of constructing a reliable anchor system from a number of poor anchors linked together. Once the anchors themselves have been identified and selected, then 2 focal points must be constructed, one each for the Main and Safety lines. Wherever possible, and irrespective of the method used, the Main line focal point should be far enough away from the cliff edge to provide a clear working area for the raising / lowering party. Conversely, the focal point for the Safety line should be constructed closer to the edge to minimise potential stretch (and therefore stopping distance) in the event of a Main line failure. Given a choice between Dynamic and LSK ropes, the latter should always be used in anchor system construction. Many crag situations will require members of the lowering / raising party to be given the security of an edge rope during the operation. Where practicable, these ropes should be attached to anchors independent of the Main and Safety line anchor systems. Particular care must be taken to ensure that no moving ropes pass over this edge line and that no unnecessary trip hazards are created. General Rules Various methods can be used to create reliable anchor systems and each situation will lend itself to a particular arrangement. There are however some general rules that will apply to most anchor systems: When constructing the anchor system, create a focal point that is in line with the direction of force. With multiple anchors, favour the strongest so that they take more force than their weaker neighbours. As a rule of thumb, ensure that the angle between ropes or tape connecting the focal point to the anchor is 90¼ or less. Avoid using ANY anchoring system that loads a karabiner in any direction other than directly along its spine - take particular care when using 25mm tape. Ensure that the anchor itself does not have any sharp edges that could damage ropes or tape. Use padding where necessary. When in doubt about a single anchor s strength, use multiple anchors. Use a minimum of 2 points per anchor system. If using rock gear use a minimum of 4 placements per system, allowing 5kN per piece. An example of an anchor system created from 2 separate, but linked, points is shown in Fig 6.9: (Note the even distribution of the load). 6-13

14 Fig 6.9: Twin anchor points with even load distribution In the absence of any other reliable anchor, ground stakes can be used, placed in series as illustrated in Fig The stakes should be placed 1 m apart, at an angle of 15¼ to the vertical. They are strongest when driven in for 2/3rd of their length and then linked by pre-tensioned ties as shown. Spider s Web Anchor System Fig 6.10: Ground Stake Anchor System One anchor system worth particular mention is the Spider s Web. Using this method, a series of less than perfect anchors can be utilised to construct one or more bombproof anchor systems. The Spider s Web may be used with any type of anchor, including ground stakes and natural features, and can be as extensive as the situation and quality of individual anchors dictates. An example of a Spiders Web is shown in Fig

15 Fig 6.11: SpiderÕs Web anchor - note that central Overhand knot may be replaced by a rigging plate, as shown in inset. Note that a rigging plate is a useful means of creating a focal point for a Spider s Web anchor system. In this case the rope is attached to the plate using screwgate karabiners and Clove Hitches, which are adjusted to distribute the load between individual anchors (not forgetting to favour stronger anchors as required). Maximising Anchor Strength When 2 anchors are joined together to form a focal point, or when an anchor rope is passed around a large object to form a loop, an angle is created. As the angle increases, the force on the rope and the anchor points also increases (unless the rope is around a single point only, when only the force on the rope will increase). At angles above 120¼ the force on the anchor points exceeds that of the load itself. As a rule of thumb, keep the internal angle between the legs of any multiple anchor to 90¼ or less. An anchor point may be strong when pulled one way, but may be much weaker if pulled in a different direction. Check that the anchor system is constructed in such a way that it will cope with both the load and the direction in which it will be applied. The diagram at Fig 6.12 shows the relationship between the load, the internal angle and the force applied to the anchor points. Note that the inverse of this relationship applies to the forces caused by change of direction pulleys as shown at Fig

16 Fig 6.12: Angle / Force relationship - (ConstantLoad) - as the inside angle increases, the force on each leg also increases Fig 6.13: Angle / Force Relationships - (Change ofdirection pulley with constant tension) - as the inside angle decreases, the force on the pulley anchor increases 6-16

17 High Strength Tie-Offs During certain operations, such as Highlines, it is wise to minimise the loss in breaking strength of the rope caused by knots or sharp turns in the rope. One method of anchoring a rope where maximum rope strength is required is by use of high strength tie-offs. Two methods are shown in Fig 6.14, one using a tree and the other using a large-wheel pulley such as the Kootenay Carriage. To gain full advantage of the high strength tie-off principle, the anchor object should be at least 10 x the diameter of the rope (ie over 11cm for an 11mm rope). Generally speaking, the number of wraps required is not dependent on the diameter of the anchor object, but rather on the amount of friction provided by its surface. The objective is to reduce the tension at the rope s termination, so that it is no longer the weak point. As a general rule, if using a tree as an anchor, the rope should be wrapped 2 or 3 times around the trunk; if using a smooth object such as a large pulley, increase the number of wraps to 4. Another means of using a high strength tie-off to minimise the loss in breaking strength caused by knots at a rope s terminations is to use a Prusik bypass. In this instance the rope is terminated as normal; say with a Figure of 8 on the Bight knot and attached to the anchor. A single 3-wrap 8mm prusik is then placed on the rope and is also clipped to the anchor. (See Fig 6.15). The prusik is tensioned, leaving a small amount (4-5cm) of slack in the rope or line between the prusik and the anchor. Under normal circumstances the prusik will hold the load, leaving the knotted section of the rope un-tensioned. Fig 6.14: High strength tie-offs 6-17

18 Should the prusik become over-stressed, it will begin to slip (as the tension reaches 6-8kN) and the rope will share the load as the slack is taken up. The gripping ability of the prusik plus the knotted breaking strength of the rope essentially brings the termination strength almost to the full un-knotted strength of the rope. Fig 6.15: Prusik by-pass A further technique used to attach open-ended tape to an anchor is the Wrap 3 pull 2 method. This method avoids placing stress on the knot and therefore gains maximum strength from the tape by minimising the loss of strength at the knot and makes it easier to untie. The open-ended tape is first wrapped 3 times around the anchor object and a Tape knot tied to secure the ends. Ensuring that the Tape knot is placed centrally and facing the direction of load, the other 2 wraps are then pulled tight and the anchor karabiner clipped as shown in Fig Fig 6.16: Wrap 3 pull 2 anchor 6-18

19 Note that great care must always be taken to avoid a dangerous 3 way loading of karabiners when constructing anchors. This is a particular risk if using 25mm tape or sewn slings to connect karabiners. Front and Back Pre-Tension Ties In some situations it may be necessary or wise to supplement one anchor with another behind the first. A useful way to ensure that the strength of both anchors is employed, rather than one purely backing up the other should the first fail, is to use a back pre-tension tie. The principle is to avoid the possibility of a domino-effect failure, which could result if there were any slack in the link between the anchor points. A 10m length of 8mm LSK is normally used to create the tie as shown in Fig 6.17, although any similar length of rope, webbing or cord can also be used. Fig 6.17 Back pre-tension tie (linked to a ÒWrap 3 pull 2Ó anchor) Use 3-4 wraps for spans less than 1.5m and more for longer spans to reduce elongation under load. Note that a front pre-tension tie can also be used to pre-tension a Main line focal point some distance from the anchors, thus preventing the focal point from creeping towards the edge as the load is applied to the anchor system. Fig 6.18 shows an example. A front tie can also be used to pre-tension the Safety line focal point, to minimise potential stretch should the Safety line be called into action. This has the added advantage of holding the Safety line focal point steady as the belayer is taking in or paying out the rope. 6-19

20 Self-Equalising Anchors Fig 6.18: Front pre-tension tie The use of self-equalising anchors was once commonplace. However, they are rarely truly selfequalising and present the potential for dangerous shock loading within the anchor system. If one anchor point fails, slack is created, and any remaining anchors are shock loaded. If a change in the direction of loading on the anchor system is anticipated, then a change of direction pulley should be placed forward of the anchor and close to the edge, in preparation, as the anchor system is being constructed. Snow Anchors It is possible to construct sound anchor systems from snow using a number of methods and snow stakes, Deadmen, snow/ice bollards and ice axes may all be used. It is important, however, to consider the relative weakness of an anchor constructed from the snow itself and in particular when being used to belay a rescue sized load. For that reason, rock or natural anchors should always be the first choice. Never trust a single snow anchor; multiple anchors with the load distributed equally are better. Also, try to keep the overall force applied to the system to a minimum (ie keep your systems light!) and avoid the use of pulley systems or techniques that allow rescuers to pull directly against a snow anchor. Choose instead techniques that help to minimise the force on the anchor system. 6-20

21 Never trust a single snow anchor. Consider the strength of the snow pack itself and choose techniques that minimise the force on the anchor system. Methods of Applying Tension When applying tension to a rope system, the first consideration is manpower. If there is plenty available, then it may be possible to achieve the required tension without recourse to a pulley system, as shown in Fig Pulley Systems Fig 6.19: Applying tension using manpower alone On occasions when there are insufficient personnel available to use manpower alone, as will often be the case, we must consider the use of a pulley system. Combinations of fixed and moving pulleys create systems that multiply the force that rescuers are able to apply, by making use of Mechanical Advantage (MA). Correct use of MA effectively reduces the pulling force required, while increasing the length of time and distance over which that force must be applied. Put another way, MA enables a rescuer to lift a load applying less force than the load itself, but over a longer distance. Pulley systems can be divided into 3 categories: Simple, Compound and Complex. In addition, most pulley systems can be rigged either by using the Main line itself or by using a separate rope, often referred to as acting on the Main line or Piggybacking. A component used with pulley systems is the Prusik Minding Pulley (PMP), introduced earlier in this chapter. Combining a PMP with a prusik to create an autobloc enables the pulley system to be reset by maintaining the tension in the main line while the pulley system itself is slackened and reset. When constructing a pulley system it is wise to construct it in such a way that the MA can be easily and rapidly altered, both up and down. In this way the MA can be adjusted to suit the situation, available manpower or equipment. 6-21

22 Simple Pulley Systems: These are characterised by having one continuous rope flowing back and forth between the pulleys attached to the load and those attached to the anchor. All pulleys attached to the load side (referred to as travelling pulleys) move towards the anchor at the same speed and all pulleys on the anchor side remain stationary. The tension in the rope remains the same throughout the system. Fig 6.20 shows an example of a Simple 3:1 pulley system in use, incorporating a PMP autobloc. Fig 6.20: 3:1 Pulley System with PMP autobloc Summary of Simple Pulley System Principles: The MA of a Simple system is determined by counting the number of ropes under tension at the load side of the system. If the end of the pulley system rope is attached to the anchor, the MA will be an even number (2:1, 4:1, 6:1 etc). If the end of the pulley system rope is attached to the load, the MA will be an odd number (1:1, 3:1, 5:1 etc). If the last pulley in the system (closest to haul team) is at the anchor, it does not add MA, but merely changes the direction of pull. The number of pulleys required for a Simple system (without a change of direction) is always the MA minus

23 In general, to incorporate a PMP autobloc at the anchor, the MA of the Simple pulley system must be an odd number (unless it is a block and tackle type system). Fig 6.21 shows some further examples of Simple pulley systems. Fig 6.21: Simple pulley systems examples 6-23

24 Compound Pulley Systems: These are characterised as one Simple pulley system acting on another Simple system. The travelling pulleys move towards the anchor at different speeds. Compound pulley systems are useful as they can provide greater MA than Simple systems for the same number of pulleys, thus reducing the overall friction loss for the same MA. Some examples of commonly used Compound pulley systems are shown at Fig Fig 6.22: Compound pulley systems examples 6-24

25 Summary of Compound Pulley System Principles: The MA of a Compound pulley system is determined by multiplying the MA of each Simple pulley system together. For example, a Simple 3:1 acting on a Simple 2:1 becomes a Compound 6:1. Equally, a Simple 2:1 acting on a Simple 3:1 also becomes a Compound 6:1. If it is important to raise the load with the least number of resets, and you are using a Compound pulley system comprised of 2 Simple pulley systems with differing MAs, have the higher MA system pull on the lower, (eg have the 3:1 pull on the 2:1 in a Compound 6:1). Remember, however, from Simple Pulley System Principles, that if you require a PMP autobloc, you need an odd-numbered pulley system. In this case you will have to decide which factor is most important, or change your Compound system to another combination that will meet both needs (ie a Compound 9:1, or a Simple 5:1). Longer throw distances for each reset can be achieved by positioning the anchor pulley(s) of the last (ie closest to haul team) Simple pulley system, far enough back to allow each Simple pulley system to collapse at the same time. For example, for both Simple 3:1s in a Compound 9:1 to collapse at the same time, the 2nd 3:1 must have 3 times the reset distance for the 1 st 3:1. This is due to the fact that 3 times more rope will be pulled through the 2nd Simple 3:1 than the 1st. The highest MA with the least number of pulleys is achieved by repeatedly compounding a Simple 2:1 on a Simple 2:1. When constructing a Compound pulley system, always consider the possible combinations that when multiplied together will equal your desired MA; then consider the advantages and disadvantages of each and determine which combination will best meet your needs, given the available equipment and working constraints. Complex Pulley Systems: Complex pulley systems are characterised by being neither Simple nor Compound. They are not commonly used in rescue work. When operating any pulley system, hauling should be carried out as smoothly as possible to avoid giving the casualty an unnecessarily bouncy ride, in addition to imposing repeated shock loads on the anchor system. As a general rule, it is best if the haul team can walk the pulley rope at a steady pace rather than performing a synchronised heaveho action. Care must be exercised when recovering a loaded stretcher to the cliff top during raises to avoid tensioned ropes and pulleys further injuring the casualty during the transitional landing phase. During Highline / Gorge Liftout operations it may be necessary to construct pulley systems for both the Main lines and the Safety / Haul rope. Alternatively, it may be possible (and easier) to construct a single pulley system that can rapidly be transferred from Main lines to Safety / Haul rope, and back again. This is dealt with in more detail later in this chapter. 6-25

26 Long Lowers and Raises Rope Joining and Knot Passing STRETCHER LOWERING AND RAISING TECHNIQUES Although RAF MRTs are provided with 100m (330ft) LSK ropes, it is quite possible that a casualty could require rescue from a cliff that exceeds the length of our ropes. The simplest (and generally quickest) answer is, of course, to just join another rope onto the end of the first and continue the lower from the original anchors systems. Note however, that you should NEVER USE AN OVERHAND KNOT TO JOIN ROPES SUBJECTED TO RESCUE LOADS. Instead, use a Double Fisherman s or Double Fisherman s / Reef knot combination as shown in Fig Double fishermans Reef knot with two stopper knots Fig 6.23: Knots for joining ropes subjected to rescue-sized loads Safety Line Considerations for Long Lowers: If more than 60m of Safety line has been paid out, a brake rack should be placed behind the Tandem prusiks (shown later at FIG:6.39) to allow the prusiks to be released if they lock-off for any reason. Release might otherwise prove impossible due to rope stretch, if using a standard RRH. Be aware also that the increasing weight of the Safety line during long lowers can lead to the Tandem prusik operator inadvertently paying out the line too fast, causing a loop of Safety line at the stretcher. This can be avoided by having one of the edge-men apply a slight reverse tension (using a gloved hand and a Hitch-hikers grip ) on the Safety line, thus ensuring that the rope to the stretcher remains snug. Of course, if it has been necessary to join 2 ropes together, it will also be necessary to pass the knots through the brake rack and Tandem prusiks, or even a pulley system. Passing a knot through Tandem prusiks is not a problem as the rope is not normally under tension; however, this may not be the case for the brake rack or pulley system. The sequence for passing a knot through a brake rack is shown at Fig The method of passing a knot through Tandem prusiks is shown at Fig Passing a knot through a pulley system is covered later. 6-26

27 Fig 6.24 Passing a knot - Brake Rack 6-27

28 Fig 6.25 Passing a knot - Tandem Prusiks Passing a Knot through a Pulley System Safety line knot pass for lower (for raise, reverse process) The technique for passing a knot through a pulley system differs slightly to that used for Tandem prusiks and brake racks. It is still a relatively straightforward operation, however, if carried out logically and in the sequence shown in Fig

29 Fig 6.26: Passing a knot - Pulley System Multi-Stage Lowers On occasion it will not be possible or practical to simply add more rope to facilitate a long lower. In such cases we will need to perform a series of shorter lowers, moving from belay station to belay station as required, with the distances between the ledges being dictated by the cliff and the length of rope available. 6-29

30 During such a multi-stage lower, a number of rescuers should descend (either by abseil or being lowered) below the stretcher to identify and prepare the next convenient ledge to receive and despatch the stretcher as soon as possible after its arrival. The advance party will prepare the new anchor systems and assist the guide(s) when the stretcher arrives. This party should also carry first aid equipment to deal with any deterioration in the casualty s condition. Having first ensured that any knots in the rope ends have been removed, the ropes are taken in carefully and laid down in flakes, ready for paying out again. If the stance is small, the stretcher must be anchored while the ropes are arranged. The ends of the rope are far better pulled / lowered down rather than thrown, to avoid the danger of the casualty being hit or stones dislodged, or of the ropes becoming caught up. The casualty should also be protected from falling stones by, wherever possible, a climbing helmet and the stretcher head-guard, which should be raised. This is, of course, much more of a danger during Horizontal lowers than Vertical. Exceptionally, the advance party can throw down loose stones before the stretcher arrives, providing that it is quite certain that there are no other people below. With enough manpower it should be possible to keep the stretcher moving down the crag, with those above abseiling or being lowered past, off the line of the stretcher, to prepare the next belay station. An operation such as this is the ultimate test of teamwork and efficiency. Although in reality it is a situation which is rarely encountered, it is one for which frequent training and practice are required to ensure a safe and efficient lower with a minimum of danger to casualty and rescuers. Lowering on Snow Under snow conditions the stretcher may be lowered from a firm snow anchor system, as described earlier, although consideration must be given to the strength of the anchors and the first choice should always be to use natural or rock anchors. When changing over anchor systems on snow, particular care must be taken to ensure that the stretcher is secure. It may be necessary to construct a separate anchor and to cut a ledge for this purpose. Using closely co-ordinated teamwork, it may not be necessary to stop a stretcher more than momentarily when lowering down a snow slope. Indeed, the stretcher can often be kept running smoothly from station to station, if two Team members go ahead to prepare the next anchor systems. Where the stretcher is of a modular design, such as the Bell Tangent, it is wise to pre-fit the skis to facilitate easy running over snow covered ground. Back-Roping the Stretcher When descending less technical ground, a few sure-footed Team members can often control the stretcher simply by walking down behind it, while holding on to the stretcher ropes. Anchor systems and belays can be provided when and if required. However, it is important that use of this technique is not taken to extremes, and that a timely decision to revert to a staged lower is taken. It is often best for the back-roping party to fan out behind the stretcher to avoid sending stones down onto the stretcher and casualty. This is particularly important when descending steep scree slopes. Conversely, when crossing boulder fields of really large blocks, it may be quicker to pass the stretcher down from hand to hand, while the back-rope party remains stationary on good stances to safeguard the move. Manoeuvring a loaded stretcher through broken ground (Fig 6.27) is particularly demanding and care must be taken when back-roping to ensure that the casualty s injuries are not aggravated by accidental rough handling. 6-30

31 Fig 6.27: Manoeuvring a stretcher through broken ground Rescuers should always be aware of their own safety and welfare, as it is all too easy to injure backs and to trap limbs and hands during stretcher operations. Securing the Casualty Common sense dictates that any casualty, whether during training or operations, must be securely attached to the stretcher before the lower or raise commences. Wherever possible a harness, either ready-made or improvised, should be used and the casualty secured to the Main line or its attachment point, in addition to the stretcher s own casualty securing straps. There are a few general rules that apply to each situation where a casualty is to be transported in a stretcher. These are as follows: 1. The stretcher must be properly belayed and tied-off prior to either the casualty being loaded or the guide(s) tying on. 2. The stretcher must be well prepared and well padded before loading the casualty. A vacuum mattress is ideal for this purpose. 3. The casualty s injuries must be considered - take care when fastening securing straps. 4. Once loaded, the casualty must be adequately protected from the elements (including helicopter down-wash) - consider the use of clear goggles for the eyes. 5. After loading, the casualty s condition and vital signs must be regularly monitored. During a long carry-off remember to consider the casualty s other needs, including reassurance and bodily functions. It is normal practice to fasten the casualty securing straps outside the casualty bag, ensuring that no pressure is exerted on any injuries. During Vertical lowers the casualty s feet may rest on the foot end cross-bar and are further secured by tying the lowest casualty strap in a figure of 8 fashion around the feet, in the form of a stirrup. Should the casualty have lower limb injuries, then a sit-sling arrangement must be employed to avoid aggravating the injuries. 6-31

32 Any ancillary equipment that is required to travel with the casualty must be securely attached to the stretcher. During training exercises, it is accepted practice to leave the casualty s arms outside the securing straps, whereas on an actual rescue the arms would normally be secured next to the sides, unless otherwise indicated by injuries. Note: Methods of loading and packaging an injured casualty are covered in Chapter 17. Control of a Lower or Raise One person must take overall control of the lower or raise. This person, who will usually be the senior Team member present, should not normally play a hands-on role and will delegate other jobs accordingly. Each individual must ensure that he understands and is capable of carrying out his assigned task. A minimum lowering team will consist of the following personnel: 1. Controller (who may double up as the Cliff-top caller). 2. Cliff-top caller. 3. Safety line operator (to mind Tandem prusiks). 4. Main line operator (operates brake rack). 5. Guide. It is also desirable to have personnel available to provide edge lift during the transition phase from horizontal to vertical. If enough personnel are available, assistants can help by ensuring that all ropes run without kinks to the Main / Safety line operators and can, if necessary, lend an extra hand on any lowering ropes. It will of course be necessary to have additional people to act as a haul team during raises. Cliff-top callers and edge lift personnel should always be secured to a separately anchored rope (beware of moving ropes running over static lines). The task of the cliff-top caller is to relay messages from the guide to the Main / Safety line operators. All personnel required to handle moving ropes should wear leather-palmed gloves to prevent rope burns, which could in turn lead to loss of control of the rope. To avoid confusion, the ropes must be identified so that each member of the lowering/raising team is aware of every rope s purpose. For the majority of rigging methods described in this chapter, the use of Main line and Safety line terminology will suffice. In addition, RAF MRTs are equipped with colourcoded ropes containing red or black flecks within the weave, thus making the job of identification easy, providing of course that ropes of different colours are taken to the scene! Main and Safety line operators should be trained to keep their ropes comfortably taut in the absence of other orders. Commands Commands should be given clearly and loudly, ideally so that each member of the lowering / raising team can hear and therefore remain aware of what is required. During the operation itself the commands DOWN, UP, SLOW, FAST and STOP should be used, with each command relating to either MAIN, SAFETY or ALL. Superfluous chatter should be avoided during any stretcher lowering / raising operation. 6-32

33 During long lowers or in windy conditions it will often be necessary for both the guide and the cliff-top caller to use radios to maintain good communications. Sequence of Events Immediately before commencing the lower or raise the controller should hold a short pre-departure brief during which he confirms that everyone is in place and that everything is ready to go. He must also confirm that the team understands the sequence of events to be followed and may conduct a quick walk round check of anchor systems etc. Only when all is ready should the operation begin. A typical sequence of events during a lower might be as follows: 1. Team arrives at cliff top. Senior Team member (Controller) assesses situation and forms a plan of action. 2. Controller assigns roles and tasks. 3. Anchor systems constructed to provide 2 focal points (1 for Main line, 1 for Safety line). 4. Stretcher prepared and tied on using appropriate method. 5. Edge lines prepared as required. 6. Team members take up assigned positions. 7. Guide tied on as appropriate. 8. Controller holds pre-departure brief and conducts walk-round to confirm that all is ready. 9. Operators take in any slack in Main and Safety lines. 10. Guide + stretcher move towards edge. 11. Edge lift and system pretension provided as required. 12. Guide + stretcher complete transition from horizontal to vertical. 13. Lower continues as required. Once over the edge, the guide must direct the lower by calling or by using a radio to pass instructions to the cliff-top caller, who will then relay those instructions to the Main / Safety line operators. The guide must be constantly looking over his shoulder for the best line of descent and must give his instructions in good time. If a prolonged halt is necessary, the Main line should be locked off at the brake rack. 6-33

34 Vectoring Vectoring of the Main line can be a useful tool, used to achieve the following during lowers and Highlines: a. Pre-tensioning of the Main line prior to edge transition, if using a high directional pulley. b. During edge transition itself, to assist the guide and make the move as smooth as possible. c. To ease the landing of a loaded stretcher during Highlines, by reducing the possibility of rope, slings and stretcher snags on the edge. Vectoring must be carried out with care and coordination, however, to avoid injury to those applying the vector and to ensure that the operation is completed smoothly and efficiently. Rigging Techniques and Considerations The method used to extricate a casualty from steep ground will depend on a number of factors including the casualty s injuries and the nature of the terrain. The terrain in particular will often dictate the use of a specific technique. In general the points to consider are as follows: The nature of the casualty s injuries. The nature of the terrain (cliff; scree; boulders; trees etc). The angle of the slope to be negotiated. The hazards associated with the terrain (to casualty, guides and other team members). The urgency of the situation (injuries, weather, daylight). Availability of manpower and equipment. The consequences of a human or system failure. Slope Angle Considerations Given that there are a number of different ways to rig the stretcher for lowering/raising, consideration should be given to the increasing tension that the Main line is subjected to as the slope angle steepens, if we are to maintain a SSSF of 10:1. Among the many variables that can affect the degree of force on the Main line, the slope angle and the load itself are most easily calculated. Whereas the slope angle is generally nonnegotiable, the load can of course be altered by using either a single or a 2-guide technique, or by selecting lighter-weight guides. Alternatively, a 2-Main line technique can be adopted. The following guidelines, which are not specific to any technique, should be used when considering the number of guides to be employed with different slope angles: For slope angles of 50¼ or less - use up to 3 guides with a single Main line. For slope angles of 70¼ or less - use up to 2 guides with a single Main line. 6-34

35 For slope angles above 70¼ - use a single guide with a single Main line or 2 guides with 2 Main lines. Detailed notes and rigging instructions for the rope rescue techniques listed below are included in the following pages: Low angle lower / raise. Vertical lower. Horizontal lower - single guide. Horizontal lower - 2 guide. Vertical raise. Kootenay Highline System. Guiding line. Pick-offs. Note that the tying on methods and illustrations refer specifically to the Bell Tangent stretcher. Where other stretchers are used it may be necessary to adapt the tying on methods accordingly, while still maintaining the safety principles described in this chapter. The construction of anchor systems, placement of edge protection and the operation of brake racks, Tandem prusiks and pulley systems are detailed earlier in this chapter and are therefore not included in the following instructions. Low Angle Lowers and Raises Many rescuers consider low-angle lowers and backroping (see earlier paragraphs) to be the bread and butter of rope rescue and it is true that for UK Mountain Rescue Teams this technique and variations of it are perhaps the most commonly used of all the rope rescue systems. Low angle technique can usually be employed on slopes of up to 50¼, although this angle could be less if the terrain is very loose or slippery. During low-angle rescues the terrain angle is not so steep that the stretcher hangs from the rope. The guides (a maximum of 3 attached to the stretcher for a 50¼ slope and up to 6 for lower angles) take most of the weight, although a rope system and belay are still required for safety, should the guides lose control. This last point differentiates low-angle rescue techniques from back-roping, where, in general, neither a fixed anchor system nor belay is required. Rescuers should be prepared to switch to a high-angle technique if conditions or terrain dictate. Only one rope is used for both lowering and raising, with the Tandem prusiks and brake rack / pulley system being attached to it, as shown in Fig

36 Equipment Required (Minimum): 1 x stretcher. 1 x 11mm LSK rope. STRETCHER LOWERING AND RAISING TECHNIQUES 3 x 60cm slings (2 for attachment to stretcher rings, 1 for attachment of guide to stretcher). 2 x 120cm slings (for attachment of guides). 1 x 12mm delta maillon. 1 x brake rack. 1 x set of Tandem prusiks. 1 x Radium Release Hitch (RRH). Karabiners as required. Anchor system components as required. Edge protection as required. 1 x Prusik Minding Pulley (PMP) (if Raising). Pulleys as required (if Raising). Method: (See Fig 6.28) a. Attach 2 x short slings (either 2 x single 30cm or 2 x doubled 60cm or 120cm with Overhand on a Bight at mid-point) with screwgate karabiners to the head-end stretcher rings and secure to delta maillon. b. Place Tandem prusiks (attached to anchor system via RRH) on the lowering / raising line. c. For Lowering: Place a brake rack (attached to the same anchor system no RRH required) on the lowering line behind the Tandem prusiks. d. For Raising: Place the PMP on raising line behind Tandem prusiks (shared anchor) and construct a pulley system as required, using the Tandem prusiks as an autobloc. e. Attach the lowering / raising line to the delta maillon using an Alpine Butterfly. Leaving a small amount of slack, the line is then attached to one of the head-end stretcher rings by a further Alpine Butterfly and screwgate karabiner as shown. The line is then extended to the foot-end guide. f. The remaining guides can secure themselves to the stretcher using 120cm slings as required. 6-36

37 Fig 6.28: Low Angle Lower 6-37

38 Vertical Lower STRETCHER LOWERING AND RAISING TECHNIQUES The Vertical lower is quick to set up and requires a minimum of equipment and personnel. Its advantages are that it entails minimum exposure to rock fall for both casualty and guide and once the rigging is complete the lower can be carried out smoothly and rapidly. The Vertical lower is best suited to long lowers over very steep or vertical terrain. It is not well suited to broken or easy angled terrain, or for casualties suffering from serious injuries or blood loss. A single guide is used for Vertical lowers. Assistance may be required with loading a casualty in a mid-crag situation. Tying on the stretcher for a Vertical lower is a relatively simple affair, requiring only a small amount of equipment, as follows: Equipment required: 1 x stretcher. 2 x 11mm LSK ropes (Main & Safety). 3 x 60cm slings (2 for attachment to stretcher rings, 1 for attachment of guide to stretcher). 1 x 12mm delta maillon. 1 x brake rack. 1 x set of Tandem prusiks. 1 x Radium Release Hitch (RRH). Karabiners as required. Anchor system components as required. Edge protection as required. Method: (See Fig 6.29) a. Attach 2 x short slings (2 x single 30cm or 2 x doubled 60cm or 1 x 120cm with an Overhand on a Bight at the mid-point) with screwgate karabiners to the head-end stretcher rings and secure to the maillon. b. Attach a brake rack (preferably on an independent anchor system) to the Main line (no RRH required). c. Place Tandem prusiks (attached to anchor system via RRH) on the Safety line. d. Attach the Main and Safety lines to the maillon by independent Alpine Butterfly s. Leaving a small amount of slack, each line is then attached to the stretcher rings by a further Alpine Butterfly and screwgate karabiner as shown. The Main line is then extended to the casualty and the Safety line extended to the guide. 6-38

39 e. The guide is further attached to the stretcher footbar by a short sling and to the Safety line by a prusik attached to his harness strong point. Any excess slack in the Safety line is taken in using the prusik. Note: On very sharp or overhanging edges consider having the guide climb down or lowered into position (on a top rope) after edge transition has been completed. 6-39

40 Fig 6.29: Vertical Lower 6-40

41 Horizontal Lower (Single Guide) STRETCHER LOWERING AND RAISING TECHNIQUES Horizontal lowers can be carried out using either one or two guides. The single guide lower is most suited to very steep (80¼+) terrain. It is not suited to broken ground or terrain where much manhandling of the loaded stretcher is required, in which case a two guide lower would be the preferred technique. It does however keep the load to a minimum, thus making it easier to maintain a 10:1 SSSF and would be the tying on method of choice should it ever be necessary to carry out a horizontal raise or Guiding line. Using 8mm LSK to Create a Stretcher Bridle Both Horizontal lowers and Highlines employ a 4-leg stretcher bridle to attach either or both the Main and Safety lines to the stretcher via a 12mm maillon. Although 4 x 120cm slings can be used for this purpose, an improved method is to use a 10m length of 8mm LSK cord as illustrated in Fig The completed bridle has a breaking strength in excess of 40kN and is tied as follows: a. Tie 2 small Figure of 8 on a Bight knots at the cord ends. Using screwgate karabiners, attach the ends to the foot-end stretcher rings. b. Moving to the head end, clip a bight of cord to a screwgate karabiner attached to each stretcher ring, with the bight passing inside the vertical head-guard support and outside of the angled support. c. Taking the mid-point of the 8mm cord, draw all 6 strands up to a point vertically above the centre of the head end back pad (Bell Tangent stretcher), and tie an equalised Overhand on a Bight or Figure of 8 on a Bight knot, to create a single point, to which the maillon is attached. Note: It is possible to position the attachment point along the long axis of the stretcher as required, to ensure that the stretcher remains level once loaded with casualties of differing size (eg children). This can also be achieved when using 4 x 120cm slings, but tends to be more complicated and less exact. 6-41

42 Equipment required: 1 x stretcher. STRETCHER LOWERING AND RAISING TECHNIQUES 2 x 11mm LSK ropes (Main & Safety). 10m x 8mm LSK cord or 4 x 120cm slings. 1 x 120cm sling (for secondary guide attachment). 1 x short sling (for optional guide attachment). 1 x 12mm delta maillon. 1 x brake rack. 1 x set Tandem prusiks. 1 x Radium Release Hitch (RRH). Karabiners as required. Anchor system components as required. Edge protection as required. Method: (See Fig 6.31) a. Create a stretcher bridle from a 10m length of 8mm LSK as described above (alternatively use 4 x 120cm slings), attached to stretcher rings and joined at maillon. b. Attach a brake rack (on an independent anchor system) to the Main line (no RRH equired). c. Place Tandem prusiks (attached to anchor system via RRH) on the Safety line. d. Attach the Main and Safety lines to the maillon using non-interlocking Alpine Butterfly s. The Main line is then extended to the casualty and the Safety line extended to the guide. e. The guide is also attached to the maillon by a sling and to the Safety line by a prusik, both of which are attached to the harness strong point. Any excess slack in the Safety line is taken up using the prusik. The guide may also find it useful to connect himself to the stretcher using a short sling to aid positioning and to assist in pulling the stretcher away from the crag. 6-42

43 Guide further secured by sling to maillon plus additional (optional) short sling to stretcher frame. Prusik on Safety line is used for position adjustment and to take up any slack. Fig 6.31: Tying on for a Single Guide Horizontal Lower 6-43

44 Horizontal Lower (Two Guides) An additional rope and a different method of tying on are required when using two guides for a Horizontal lower. Note also that it may not be possible to maintain a Safety line SSSF of 10:1 when using 2 guides. (A rescue load of 2.8kN acting on a rope with a knotted breaking strength of 22kN (after 33% loss due to knots) gives a SSSF of just under 8:1). For that reason, it is best to avoid using heavy (80kg+) guides for this method. It is most suited to steep (60¼ - 80¼), but not vertical (80¼+) terrain, or where considerable man-handling of the stretcher may be necessary. Equipment required: 1 x stretcher. 3 x 11mm LSK ropes (Main 1& 2 + Safety). 10m x 8mm LSK cord or 4 x 120cm slings (for Safety line attachment). 6 x 120cm slings (2 for Main line attachment, 4 for guides). 2 x short slings / prusiks (for guide positioning attachments). 1 x 12mm delta maillon. 1 x brake rack. 1 x set of Tandem prusiks. 1 x Radium Release Hitch (RRH). Karabiners as required. Anchor system components as required. Edge protection as required. Method: (See Fig 6.32) a. Create a Safety line stretcher bridle from a 10m length of 8mm LSK as described above (alternatively use 4 x 120cm slings), attached to stretcher rings and joined at maillon. b. Attach a brake rack (preferably on an independent anchor system) to both Main lines (no RRH required). c. Place Tandem prusiks (attached to anchor system via RRH) on the Safety line. d. Attach the Main lines to the 2 x 120cm slings (with Overhand on a Bight knot at mid-point), attached to head and foot end stretcher rings using screwgate karabiners. The Main lines are then extended to the guides. 6-44

45 e. The guides are also attached to the Safety line maillon by a 120cm sling and to the Main line by a prusik, both of which are attached to the harness strong point. Any excess slack n the Main line is taken up using the prusik. The guide may also find it useful to connect himself to the crag-side of the stretcher using a short sling, to assist in pulling the stretcher away from the crag. f. The Safety line is attached to the maillon by an Alpine Butterfly and extended to casualty. Notes: 1. 1 or more of the Safety line bridle legs may be temporarily removed to assist casualty loading. 2. Care is required to avoid tensioned Main lines from running over the Safety line at the top of crag. 6-45

46 Fig 6.32: Tying on for Two Guide Horizontal Lower Stretcher Raises and Highlines There may be occasions when the most appropriate method of evacuating a casualty is by means of a raise or a tensioned Highline. Possible situations include sea cliffs, where access to the base is difficult or impossible, or where it is desirable (ie safer) to draw the casualty and guide away from the cliff, due to danger of loose rock or scree. In the first instance, a relatively straightforward Vertical raise may well be the simplest and quickest option, while for the second situation a more complicated Highline rescue is dictated. Highlines, which are fully described later, may also be used to good effect to extract a casualty from a gorge or other inaccessible location, or to facilitate a river crossing with a loaded stretcher. For any technique involving tension and / or raising, it makes great sense to ensure that the load is kept to a minimum. This will reduce the strain placed on the anchor system and will allow a lower mechanical advantage pulley system to be used, thus speeding up the whole operation. For these reasons, it may be preferable to raise the stretcher without a guide. However, it must be remembered that it can be all too easy for the stretcher to become snagged on projecting rocks during a raise, which could lead to difficulties, or to the system becoming overtensioned. There is therefore no strict rule regarding the use of guides and a decision must be made on the day, once every aspect of the operation has been considered. Vertical Raise The method used when tying on for a Vertical raise is similar to that used for a Vertical lower with the addition of two 240cm slings, attached to the vertical struts below the stretcher mid-point to create an extended stretcher bridle. This extended bridle may be required to facilitate the stretcher s transition from vertical to horizontal. Also required will be a pulley system with a Prusik Minding Pulley (PMP) autobloc to act on the Main line (as described earlier in this chapter), a PMP on the Safety line Tandem prusiks and an (optional) independent 5:1 Jigger pulley. With the stretcher initially tied on as for a Vertical lower, it will be necessary to pre-place or add additional components as shown in Fig 6.33a & b to perform the raise. Note: If it is clear from the outset that the operation will involve a lower followed by a raise, it is best to pre-attach the 240cm slings using a Larksfoot knot to the vertical struts below the mid-point of the Bell stretcher. The slings are then passed underneath the stretcher bed and joined with a screwgate karabiner, which should be secured to an easily accessible place such as the head-guard, ready for use. Ensure that no loose loops of sling are left hanging below the stretcher, as these will all too easily catch on any projection. Equipment required: (Assuming that the operation involves a lower followed by a raise and that a guide is to be used) 1 x stretcher. 2 x 11mm LSK ropes (Main & Safety). 3 x 30cm slings (2 for attachment to stretcher rings, 1 for attachment of guide to stretcher). 1 x 12mm delta maillon. 6-46

47 1 x brake rack. 1 x set of Tandem prusiks. 1 x Radium Release Hitch (RRH). Karabiners as required. Anchor system components as required. Edge protection as required. Additional Equipment for Raise: Method: 2 x 240cm slings with screwgate karabiner. 2 x PMP (1 for Safety, 1 for Main). 1 x 8mm prusik (to create PMP autobloc on Main). Single pulleys and additional prusiks as required (for Main line pulley system). Also, if a separate 5:1 Jigger pulley is to be used: 2 x double pulleys. 10m x 8mm LSK (for Jigger pulley). Additional anchor for Jigger pulley. Stage One: a. Tie on as for a Vertical lower, but with PMP pre-placed on Safety line and with 2 x 240cm slings attached to vertical struts and stowed as described above. b. Prepare PMP for pulley system autobloc and single 8mm prusiks as required, ready for use. c. Continue with lower until ready to convert to raise. d. Place single 8mm prusik on Main line below brake rack and clip in to belay (on separate karabiner). e. Push prusik forward and transfer load from brake rack to prusik. f. Remove brake rack and replace with PMP and autobloc. g. Place additional prusiks and pulleys to construct a 5:1 pulley system on the Main line. (See Note 2 and Fig 6.33a). h. Raise load until stretcher is just below the edge and within reach of the cliff top caller 6-47

48 or edge men. Stage Two: (See Fig 6.33b) Notes: STRETCHER LOWERING AND RAISING TECHNIQUES i. If the edge is overhung or right-angled, it will be necessary to use the extended bridle to ensure a smooth transition from vertical to horizontal as the stretcher is landed. This is most easily and efficiently achieved by dead-ending the 5:1 Main line pulley system by tying a Figure 8 on a Bight behind the PMP autobloc and clipping this to the anchor, creating a 4:1 pulley system. The pulley system is then transferred from the Main line to the 2 x 240cm slings that form the extended bridle. Alternatively, an independent 5:1 Jigger pulley may be used for this purpose. j. Before commencing the final raise, ensure that the 240cm slings pass under the stretcher and primary attachment slings, and that they are not caught up in the stretcher locking mechanism. k. Using the transferred 4:1 or an independent 5:1 Jigger pulley, haul the stretcher over the edge to complete the raise. 1. Where the edge is low angled or rounded, it may not be necessary to employ the extended stretcher bridle and associated pulley system, in which case the raise will continue as described in sub-paras a tog. 2. A 5:1 pulley system is a wise choice as it can rapidly and easily be converted to either a Simple 3:1 or a Compound 9:1, simply by moving or removing one pulley. 3. The pulley system in use should be fully reset ias the stretcher nears the edge, so that the vertical to horizontal transition can be completed in one move. 4. Without its own PMP autobloc to allow a reset, the Jigger pulley provides a once-only opportunity to land the stretcher effectively. 5. During operation of the Stage Two pulley the Main line should not be tensioned. 6. Care must be taken to avoid the casualty becoming trapped or injured by tensioned ropes during the transition phase as the stretcher moves from the vertical to the horizontal. 7. The method described assumes that the tail of the Main line is used to construct the Main line pulley system. It is also possible, and perfectly acceptable, for an independent LSK rope to be used for this purpose. 6-48

49 Fig 33a: Vertical Raise - Stage One 6-49

50 Fig 33b: Vertical Raise - Stage Two Rigging for a Tension Lower or Gorge Liftout - The Kootenay Highline System The RAF MRS has adopted the Canadian Kootenay Highline System (KHS) as its primary method for transporting a load over a span, using tensioned ropes. As such the KHS has replaced the Tension lower and Gorge liftout techniques used previously. The following notes are based on those provided by Rigging for Rescue, and apply primarily to the KHS. Highlines can be much more practical for rescue work than is commonly assumed and with practice can be rapidly set up and completed. It is important, however, that we appreciate the high levels of force that can easily be placed on the Main line(s), if some key principles are not taken into account. By observing these principles, we can construct effective, efficient and safe Highlines that can frequently be more practical than other techniques available. There is no one correct way way to rig a Highline and many factors must be taken into consideration. The key variables that determine how a KHS should be set up are: the span, the angle between end stations, length of ropes, available equipment, access limitations to either side, the terrain, number of 6-50

51 people, the size and location of the load and communication considerations. Team members should practice various ways of setting up Highlines, so as not to resort to just one known method. Each method can and should be adapted to the specific situation at hand. Key Principles The key principles to be observed when constructing a KHS are: Minimise the loss of breaking strength in the Highline s Main line by having no knots or sharp bends in it. Also, anchor the fixed end of the Main line with a high strength tie-off, as described earlier in this chapter. Attach the tensioning pulley system to the Main line with Tandem 8mm prusiks; they act as a gently acting slipping clutch to prevent overtensioning (See Fig 6.34). Fig 6.34: Tensioning system for a Single Main Line Attach the load by hanging it from a device capable of sustaining multi-directional forces such as a Kootenay Carriage or a rigging plate. There are many ways to accomplish this. Consideration must also be given as to whether the load will be suspended from one or two attachment points and if the Safety line will be one continuous rope or whether two separate ropes will be used. Some examples of various combinations are shown in Fig Fig 6.35: Examples of Highline load attatchment to Kootenay Carriage(s) 6-51