Origin: The name Whoopie Sling was apparently first recorded in Tree Care Industry, Volume 11 (2000). The description makes it clear that the Sling was developed by and for Arborists and it also describes the use of a pulley block on the Sling. The Whoopie Sling is still widely used by Arborists.

Other uses: Today the Whoppie Sling is used in camping to tension a hammock. The sling is usually tied in material with minimal elasticity. Once tightened, the hammock is more likely to sag due to stretch in the hammock itself or a bend in a supporting tree. These slings are also used in Marine Yards where the adjustable length facilitates balancing a load.

Name: There appears to be no authoritative source for the “Whoopie” name despite its creation within fairly recent memory. Please write to me if you think you know the source.

Material: Whoopie Slings are typically made in 12-strand braided rope. Ropes differ in the tightness of their braid and, therefore, in the ease with which an end can be threaded along inside. A wire pusher is often useful.

Preliminary Measurements: These measurements are approximations for high modulus fibers such as Dyneema^®, Tenex^®, Vectran^®, Technora^® or Kevlar^® based on: Atlantic Braids. In summary, where “D” = the rope diameter, make six Marks:

• Mark Start of Taper at about 10xD from the end.
• Mark 1 – Entry Mark for Total Length of Bury – about 40xD from the end.
• Mark 2 – Add Length for Loop and make Exit Mark (2) Opposite Mark 1.
• Mark 3 – New Entry Mark about 75xD from the Mark 2.
• Mark 4 at about 10xD from the other end.
• Mark 5 at about 15xD from the other end.

Other Fibers: For less slippery fibers such as polyester, nylon, or polyolefins, Mark 1 can be at 25xD, and Mark 3 can be at 50xD from Mark 2.

Technique: For photography this Whoopie Sling is very short, the length of each bury is very short, and the Initial end was not tapered.

• Align Marks 1 and 2 and make the Brummel Eye Splice.
• Thread the short end through, taper it and smooth it back inside.
• Thread the Long end from Mark 3 to 2. (in the animation it exits well short of Mark 2.)
• Thread the Long end from Mark 4 to 5 and pull tight.
• Leave the Long end untrimmed and smooth it back inside to make the Handle.

Details: The Initial Short end is tapered to minimize stress on the fibers of the Brummel Eye Splice. For the Long end there is no benefit in a taper. In fact the absence of a taper makes the end a better stopper and reduces the chance that it might get pulled into the adjustable section. The size of the eye splice can be varied and the size of the adjustable loop will depend on how much rope is used.