A single-leg sling is a fundamental type of lifting or rigging equipment used across industries to lift, secure, or move loads. Consisting of a single length of material with one connection point at the top and bottom, it is designed to seamlessly connect a load to a lifting device like a crane or hoist.
Single-leg slings can be effectively deployed in three main configurations based on load dynamics:
The most straightforward application. The sling connects the crane hook directly to the load in a straight vertical pull. Ideal for perfectly balanced loads with designated lifting eyes.
The sling is routed completely under the load, and both ends are connected to the lifting device at the top. This effectively distributes the weight and increases the overall lifting capacity.
The sling wraps around the load and is threaded back through itself (or its hardware). As tension is applied, it provides a tight, cinched grip, ideal for securing loose materials or loads that may shift.
Two identical single-leg slings may be used in combination to form, in effect, a two-leg sling. Care is necessary to ensure that the main hook of the lifting appliance is not overcrowded. It is highly recommended that the upper ends of the sling legs be connected via a master link or shackle.
Where this is done, the legs must be symmetrically disposed, and the angle of any leg should not exceed 45° to the vertical. For rating purposes, the combined SWL when the legs are between 0° and 45° to the vertical is 1.4x the SWL of the single leg.
We appreciate the following crucial safety guidance contributed by Mr. Knut Buschmann of Unirope Ltd.
A single-leg WIRE ROPE sling shall NEVER be used as a "single" sling alone in a straight vertical lift. Allowing a single wire rope to suspend a free-hanging load will cause the rope to forcefully unwind, destroying the core structure and leading to a catastrophic failure.
While all single-leg slings display a capacity tag, this denotes the hardware capacity, NOT an application suggestion. Single-leg wire rope slings must only be used in pairs (or more) to form a multiple-leg arrangement so they counteract each other and are prevented from rotating.
The Right Tool for the Job: This is precisely why Chain Slings and Flat Web Slings are chosen for single-point vertical lifts—they do not structurally rotate under load. Be aware that roundslings and multi-strand synthetic ropes (e.g., 12-strand) will also lose immense structural strength if allowed to freely spin.
For further technical reading, visit Unirope's Guidelines on Single Leg Slings.
