Mini pulley systems – a rope-rescuer’s multitool?

The Rock Exotica Aztek developed in conjunction with Reed Thorne led the way in the modern era and has rightly become the leading high-strength ‘mini’ pulley system. Much larger and stronger than the CPS, it still manages to remain below 5 lbs/2.2 kg using the shorter rope option and provide 36kn/8000 lb MBS.

There’s nothing new about pulley systems that are small enough to put in a bag and take anywhere. They were being used in rescue in the 80s but they have seen a renaissance in recent years culminating in some of the most technically advanced designs to date. Ade Scott from Technical Rescue magazine explores why all rescue personnel should have one.

Everything in rescue is cyclical. There are seasonal or at least periodic fashion trends, sometimes it’s a trend for an entire discipline and sometimes it’s trends within each discipline. Water rescue remains big but 15 years ago everybody was getting rid of their swiftwater capabilities. Trench rescue was a hot topic for a while in the late 90s and every team with a USAR capability trained exhaustively for it. Then 911 changed the focus to structural collapse and USAR trumped everything including water rescue and rope rescue. Until, several years on, fire departments began to realise that collapses on that scale were few and far between and even when they did occur it was generally dependant on the first-on-scene to save what few lives could be saved. Instead, climate change saw a long-predicted increase in flooding so water rescue teams and re-tasked USAR and Technical Rescue Teams became the norm. Unless your area has a constant identifiable risk like recreational water, annual frozen lakes or climbing cliffs close to urban areas, we tend to be quite reactive in rescue because budget constraints don’t allow for teams to be ‘idle’ for long.

The trick is to purchase equipment that can be used in a range of disciplines so that budgets can be easier to justify – helmets, stretchers, tripods and portable cutting equipment can all be multi-discipline. Recently, we have seen an explosion in lightweight pulley systems sold as a complete kit rather than as components. This again is a cyclical trend since we were using mini pulley systems back in the early 80’s albeit under the name ‘Casualty Pulley System’ because it was used primarily to transfer a casualty’s body weight in a pick-off rescue. But it seems that once one manufacturer introduces an updated version of something, everyone else follows and techniques for using such equipment become diversified and ultimately standard operating procedure. Mini pulley systems are perhaps the single unifying technical product in rope access and rescue – every single rope user, whether they are involved in rope rescue, water rescue, rope access or tree/storm work will benefit from the inclusion of a mini-pulley system in their inventory to provide an immediately deployable hauling capability. We have long-advocated the use of pre-rigged pulley systems over components, whether they be ‘mini’ or full size systems. It used to be the case that rope rescuers built their pulley system on-site and in the case of remote area rescuers needing to travel light this is still the case. But the extra time taken to construct a complex 5:1 or 6:1 system and the scope for getting it wrong under pressure or in poor light and weather conditions mean that being prepared with one you made and checked earlier is a much better idea. You still need to maintain those core skills in building various mechanical advantage systems from scratch but operationally, forget it. Take a pre-rigged system in a bag. The larger systems using 10mm to 13mm (1/2”) ropes that are hundreds of feet or metres long are a team item but as a mini pulley system the smallest can be personal issue.

ISC Haulerbiner used as an adjustable stretcher bridle allowing the stretcher to be oriented from horizontal to vertical to negotiate restricted access points. In this example, only two Haulerbiners have been used but for trickier hot-loading of the casualty it may be better to use four, one on each leg of the bridle.

The term ‘mini’ is a somewhat arbitrary definition since some are perfectly capable as full size systems so in a recent Guide we published in TECHNICAL RESCUE magazine we defined it as a complete system weighing 5lbs/2.2kg or less and therefore capable of being carried on a harness. We featured some 20 models in that Guide but we can narrow down the most iconic recent systems to the Rock Exotica Aztek, Petzl Jag, ISC Haulerbiner and DMM RPM. These four models were purpose designed to be incorporated into a pulley system as distinct from simply combing existing off-the-shelf pulleys to create a system. Our original mini-systems utilised yacht pulleys since these were the smallest available devices at the time capable of handling the loads and abuse likely to be handed out during rescue. There are still a number modern variants that use yacht pulleys because they remain very high strength, capable devices that see as much development for yacht racing as we see in rope rescue, probably a lot more. But there’s something more reassuring about using kit specifically designed for rescue and especially in kits strong enough to be used in place of a full-size pulley system. The term ‘mini’ doesn’t necessarily mean a diminishing of load capability but you’re not really going to use the larger DMM RPM and Rock Exotica AZTEK for snatch pick-off rescues or as a stretcher bridle although they will clearly function well enough for either use but it would be an expensive and bulky option. Equally you won’t be using the Petzl Jag or ISC Haulerbiner to lift a full-grown cow out of mud or stabilise a quarter tonne concrete block.

SAR Products modern version of the original Troll CPS produced in the early 80s still uses stainless yachting pulleys with nylon sheaves and a 6mm cord which is why this is still one of the smallest and lightest systems.

Aside from the obvious pulleys and rope/cord, the key component in a ‘system’ is a progress capture device, in other words, some means of holding the load you’ve just hauled when you let go or reset. This might be a hard cam, effectively an ascender where the cam clamps the rope against the cam enclosure/body or it might be a ‘soft’ option, usually a prusik cord as you can see in the RPM and Aztek systems. A progress capture cam has been built into some devices like the ISC HaulerBiner or it may simply have a ‘V’ shaped wedge in which to jam the cord as we used to have on our old Casualty Pulley Systems.

You may need to hold the load repeatedly during resets if you are piggybacking your pulley system to a longer hauling rope in which case you will have another camming device or prusik hitch attached to that rope from a separate anchor. Depending on strength and the rope diameter, your mini-pulley system can be used for:

The latest variant and perhaps the most versatile system is the DMM RPM which is super-strong at 50kn and features pulley blocks that can be changed from single to double sheave and even con-joined to create a double swivel block for highlines.

Hauling live loads

Including a rescuer and/or casualty (ALWAYS with a belay) and animal rescue

Hauling/stabilising heavy weights

Especially in USAR situations requiring displacement of large blocks – this will usually be from a high directional anchor on a tripod or A-frame. In storm work to counter the lean of a tree or heavy branch for stabilisation or removal

Casualty pick off
Stretcher orientation
Tensioning highlines/tramways
Tensioning or ‘guying’ masts
Self rescue
Temporary load holding

During replacement or swapping of anchors in rope rescue

Vehicle rescue

Stabilising and hauling vehicles trapped in mud or on a slope – this would normally use a full-size pulley system but any system using 8mm rope or larger will cope. Remember that you would not normally use the same pulley system for live loads as you do for very high load USAR or vehicle recovery work.

Our original use for mini-pulley systems was for casualty pick-offs and stretcher orientation so the Petzl Jag and ISC Haulerbiner with their mesh cover over the moving rope strands are the modern incarnations of this. Haulerbiner in particular has gone to the trouble of incorporating integral plastic rollers into the carabiner frame to provide a 6:1 or 7:1 mechanical advantage using only 6mm cord so it’s very light at around half a kg or 1.25 lbs. Both the Jag and Haulerbiner have limited travel distance and are perfect for casualty pick off rescues where the casualty is hanging on a rope or lanyard and you only need to lift them a short distance to unclip them and attach to your own system. They are also small and light enough to be used on your stretcher bridle giving complete control over orientation. The casualty’s body-mass distribution often alters the orientation of your pre-rigged system so that when loaded the stretcher may become ‘head-up’ when you wanted slightly ‘head-down’ (for trauma victims) or angled away from you when you wanted to angle towards you for easier monitoring. Generally of course, you’ll simply want it level so the ability to easily adjust each leg makes this simple. Some of you will rightly point out that you already use prusiks on your stretcher rig to provide adjustability but mini-pulley systems will release far easier and far smoother under load than a prusik. Nevertheless, if cost is a barrier, prusik adjustment works admirably. Where the limited travel systems like Jag and Haulerbiner and the original Troll/SAR Products CPS come up short of the larger systems exemplified by the Aztek and RPM systems is in strength, rope/cord diameter (in terms of ease of grasping and hauling) and the throw length. These two models use high strength alloy sheaves and cheeks with sealed bearings that handle 8-10mm rope as standard but can accept even larger diameters up to 13mm/half inch. Both the Aztek and RPM use swivel eyes and this is fundamental in avoiding one of the nightmares of hauling – a twist. When the strands rub against each other you can increase the work you have to do exponentially. It will also put everything under increased strain and can lead to catastrophic failure of your weakest component. Don’t forget that the pulley units may be rated to 36-50kN/8-11,000 lbs but it’s a safe bet that your rope or anchor or even carabiners won’t be.

It is possibly unfair to lump in the true mini-pulley systems that use small diameter rope/cord to give relatively short travel for a single body-weight load with the heavy-duty systems like RPM and AZTEK that could just as easily be loaded up with 200m/600ft of rope and used to shift a battleship. These things generally come down to money. In an ideal world, your team kit would include an RPM or Aztek strength system costing somewhere between $300 and $800 and your personal issue would include one of the smallest systems costing between $130 and $270. If you have to choose just one it will probably be based on cost but any of the quality Mini-Pulley systems from recognised rope-rescue manufacturers will serve you well in a variety of uses. They’re like the Swiss Army Knives of the rope rescue world. A worthwhile renaissance.

Piggybacking a haul rope

A Rescuescender used as the haul- cam in a DMM RPM haul system. You must ensure that any hardware you use like ascenders and descenders that are intended to ‘grab’ or ‘squeeze’ rope actually do operate as intended on your specific rope. You may hear some folk say that you shouldn’t use a particular device because it severs or damages rope. They all will at some point either due to high load or high impact load but some are more aggressive than others and we never use toothed cams for anything more than single body weight. Always test hardware on the specific rope that you use to ensure they work OK together. When you have a mechanical advantage system it’s much easier to overload the system at the haul cam, especially if the haul rope experiences increased friction or the load becomes snagged. ALWAYS use a second belay/safety rope with a haul system.