The 20–80 Rule in Action: Building the Minimal Mechanical Advantage Kit

In rope rescue, complexity can be your enemy. Too many devices, too much gear, and too many choices under stress can slow a team down and increase risk. That’s where the 20–80 Rule comes in: with about 20% of the gear, you can accomplish 80% of the work. Applied to mechanical advantage (MA) systems, this means a compact, versatile kit that covers nearly every hauling task you’re likely to face.

This article takes the 20–80 principle from concept to practice. We’ll identify the actual pieces of equipment you need, show you how to assemble four proven MA systems from this minimal kit, and explain when and why each system is used.

Why the 20–80 Rule Matters

Rescue environments demand speed, efficiency, and clarity. Every additional device or knot introduces more opportunities for mis-rigging or time lost. By narrowing your kit to a core set of components, you:

• Simplify decisions in high-stress environments.

• Accelerate rigging time without sacrificing safety.

• Reduce training overhead, since fewer systems need to be mastered.

• Increase adaptability, because the same gear can be reconfigured into multiple solutions.

The Minimal Kit: 20% Gear, 80% Capability

Here’s the short list that provides maximum versatility in mechanical advantage systems:

Pulleys

• 1 × high-efficiency double pulley (ball-bearing, PMP style).

• 1 × high-efficiency single pulley (to complement the double).

Progress Capture Devices (PCDs)

• Prusiks (6–8 mm cord, 2–3 loops) — simple, lightweight, reliable.

• Mechanical option (e.g., Petzl Rescucender, Maestro, Clutch) for faster resets and higher efficiency.

Pre-Rigged Kits

• AZTEK system — versatile 4:1/5:1, doubles as a personal edge kit.

• Petzl JAG system — compact, efficient 4:1 for tensioning, pickoffs, and short-haul needs.

Cordage & Webbing

• 2 × 5 m prusik loops (anchor slings or backups).

• 1 × 10 m webbing/sling for redirects or anchor extensions.

This kit fits in a small bag and weighs little, yet builds the backbone of your rescue hauling systems.

Four Core Systems from the Minimal Kit

1. The 3:1 Z-Rig

The Z-rig is often the very first MA system rescuers learn — and for good reason. It’s quick to build, easy to understand, and requires only the simplest gear. The name comes from the “Z” shape the rope makes when the system is tensioned.

In practice, a rescuer attaches a pulley to the load, routes the rope back through a progress capture at the anchor, and then hauls from the free end. This arrangement triples the input force, giving a single rescuer or a small team enough leverage to move moderate loads.

Key Points:

• Gear needed: Single pulley, prusik or mechanical progress capture.

• Strengths: Fast, intuitive, excellent for edge transitions or short lifts.

• Limitations: Limited stroke length; resets can slow progress.

• Efficiency: Around 2.5:1 actual MA depending on pulley efficiency.

2. The 4:1 Block-and-Tackle

When the load is heavier or the raise is longer, rescuers turn to the block-and-tackle. Using a double pulley at the load and a single pulley at the anchor, the rope weaves back and forth to create four supporting strands. This spreads the weight efficiently and reduces haul effort significantly.

The block-and-tackle shines in vertical raises, confined spaces, and situations where a compact, powerful system is needed. While it requires one more pulley than the Z-rig, it provides greater force multiplication and smoother hauling.

Key Points:

• Gear needed: Double pulley, single pulley, progress capture.

• Strengths: Compact, more power than a 3:1, ideal for small haul teams.

• Limitations: Slightly slower to rig; more rope needed per unit of lift.

• Efficiency: Roughly 3.2:1 actual MA.

3. Piggyback Haul (3:1 on Mainline)

Not every challenge in rescue requires a full re-rig of the main system. Sometimes, a rescuer just needs a quick boost — and that’s where piggyback hauls come in. By clipping a pre-rigged kit like the AZTEK or JAG directly onto the main rope, teams can add a temporary 3:1 or 4:1 to lift, tension, or adjust without disrupting the primary setup.

Piggyback systems are problem-solvers. They’re especially useful for passing knots, adjusting edge transitions, or tensioning a system under load. Because they’re compact and pre-assembled, they can be deployed in seconds.

Key Points:

• Gear needed: AZTEK or JAG kit.

• Strengths: Rapid deployment, high control, solves problems without full re-rig.

• Limitations: Short hauling range; best for adjustments rather than long raises.

• Efficiency: High, especially with sealed bearing pulleys in modern kits.

[Insert diagram of piggyback on mainline]

4. Twin-Tension Assist (TTRS with JAG/AZTEK)

As rope rescue evolves, twin-tension rope systems (TTRS) are becoming the standard for mainline operations. In these setups, two ropes share the load, providing redundancy and balanced control. But friction from devices like the Maestro, Clutch, or MPD can make hauling less efficient.

That’s where compact 4:1 kits like the JAG or AZTEK come into play. By integrating them into each tensioned rope, teams can add mechanical advantage to overcome device friction, fine-tune balance between ropes, and ensure smooth, controlled raises and lowers.

Key Points:

• Gear needed: 2 × compact 4:1 kits (e.g., JAG, AZTEK).

• Strengths: Enhances efficiency in twin-tension operations, balances rope friction.

• Limitations: More gear-intensive; requires training for balanced hauling.

• Efficiency: Provides precise control when paired with friction-managing devices.

Why This Kit Works

The minimal kit doesn’t just reduce clutter — it works because each piece plays multiple roles:

• Double + single pulley: Build a 3:1, 4:1, or compound haul.

• AZTEK/JAG kits: Serve as pre-rigged hauls, progress captures, or tensioning devices.

• Prusiks: Function as anchors, backups, and PCDs.

• Webbing: Redirects, anchors, or extensions.

Together, they form a toolkit that covers 80% of operational hauling needs in rescue, training, and industrial access.

Visual Reinforcement

To bring the concept home, your team should:

• Practice each of the four systems until you can build them in under two minutes.

• Compare the force-to-distance tradeoff between them (e.g., 3:1 vs. 4:1 stroke lengths).

• Use load cells, if available, to see actual vs theoretical MA in action.

A comparison table like the one below makes an excellent training reference:

Conclusion

The 20–80 Rule is more than a concept — it’s a practical framework for building a rescue kit that is lean, versatile, and effective. By mastering a handful of pulleys, progress captures, and compact pre-rigged kits, your team can handle the vast majority of hauling situations without dragging extra equipment into the field.

The next step is practice: take this minimal kit, rig each system, test it under load, and watch how quickly your confidence grows. With repetition, you’ll prove the 20–80 Rule in your own operations — fewer tools, faster setups, safer rescues.

Peace on your Days

Lance