Select a rope rescue system, enter load weight and efficiency — get haul force, rope multiplier, and system notes. Covers Z-Rig, Piggyback Z, C-Rig, Drop C, and custom MA.
| System | TMA | AMA @78% | Haul Force (200 lb) | Best Use |
|---|---|---|---|---|
| Z-Rig | 3:1 | 2.3:1 | ~86 lb | Standard haul, most rescues |
| C-Rig | 4:1 | 3.1:1 | ~65 lb | Heavier loads, confined space |
| Drop C (6:1) | 6:1 | 4.7:1 | ~43 lb | Very heavy loads, limited haulers |
| Piggyback Z (9:1) | 9:1 | 7.0:1 | ~29 lb | Max advantage, complex setup |
| 5:1 Compound | 5:1 | 3.9:1 | ~51 lb | Litter hauls, mid-range advantage |
The Z-Rig is the most common rope rescue mechanical advantage system. Two pulleys and the load anchor create a Z shape. Pull 3 feet of rope to move the load 1 foot. Quick to build, easy to reset, and sufficient for most single-victim rescues with 2–3 haulers on a 200 lb load.
A 3:1 Z-Rig attached to the haul strand of another 3:1 Z-Rig. Theoretical advantage is 3 × 3 = 9:1. Practical advantage is lower due to compounding friction. Used when very heavy loads or very few haulers require maximum mechanical advantage. Setup is complex and rope consumption is high.
A 4:1 compound system using three pulleys. The rope runs from anchor through two traveling pulleys to the haul point. More efficient rope use than a Piggyback Z for a similar result, but slightly more complex to build correctly. Common in confined space and low-angle rescue.
A 6:1 compound system, effectively a 3:1 pulling through a 2:1. Provides high advantage with manageable rope consumption. Useful for heavy patient packaging, litter rescues on steep terrain, or when hauler count is limited.