A Whoopie sling is a type of adjustable rope or cord loop, commonly employed in rigging, arboriculture, and outdoor recreation. It is characterized by its simple, lightweight, and highly adjustable design, constructed from a single piece of high-strength, low-stretch rope, typically a hollow-braid synthetic fiber, which forms a continuously adjustable loop.
Construction and Mechanism The Whoopie sling is fabricated using a specialized splicing technique, often referred to as a "bury" or "Chinese finger trap" splice. This method involves threading one section of the rope back into its hollow core, creating a splice that tightens and locks under tension. Typically, one end of the sling forms a fixed eye (loop), while the other end is threaded through an extended section of the hollow-braid rope, which acts as the adjustable leg. By sliding this threaded section, the effective length of the adjustable loop can be precisely controlled. The friction and compression of the rope buried within itself create a secure hold that prevents slippage when under load, yet allows for easy manual adjustment when not under full tension. Materials like Ultra-high-molecular-weight polyethylene (UHMwPE, e.g., Dyneema, Spectra, Amsteel) are frequently used due to their exceptional strength-to-weight ratio and low stretch characteristics.
Applications Whoopie slings are favored for applications requiring lightweight, strong, and easily adjustable connections. Common uses include:
- Arboriculture: Utilized for connecting rigging blocks, redirecting ropes through false crotches, or providing support for tree limbs in tree climbing and removal operations.
- Hammock Suspension: A highly popular choice for suspending camping hammocks due to their minimal weight, ease of adjustment, and often gentler impact on tree bark compared to narrower ropes or straps without protection.
- Camping and Backpacking: Employed for guylines, clotheslines, bear bag hanging systems, or general utility tie-downs where quick and secure adjustment is beneficial.
- Marine and Industrial Rigging: Used in lighter-duty applications as an adjustable soft shackle or versatile rigging sling where a strong, non-metallic, and adaptable connection is desired.
Advantages The primary advantages of a Whoopie sling include:
- High Adjustability: Offers a wide and precise range of length adjustments with minimal effort.
- Exceptional Strength-to-Weight Ratio: When made from UHMwPE fibers, they provide remarkable strength while remaining extremely light.
- Simplicity and Reliability: Lacks mechanical parts or complex knots, reducing potential points of failure and simplifying operation.
- Non-Damaging: The relatively broad surface area, especially when used with tree-friendly straps or directly around robust anchors, can be less damaging than thin ropes or wires.
- Compact Storage: Can be easily coiled and stored, taking up minimal space.