PRO Tip: Poacher's Knot Versus Scaffold Knot
The poacher’s and scaffold knots are very similar and commonly mistaken for each other and the names are incorrectly used interchangeably. The poacher’s knot is a loop made by tying half of a double fisherman’s bend (two wraps) and a scaffold knot is loop made by tying half of a triple fisherman’s bend (three wraps). The knots are used when a compact knot is needed that pulls tight and grips an object. Examples of use would be connecting an end of a mechanical advantage system (MA) to the becket on a pulley or an escape line to a carabiner/hook. They are great knots to incorporate when you need an MA to be as compact as possible on a vertical raise with a high anchor point such as an Arizona Vortex or tripod in a confined space rescue. In some cases, a scaffold knot will provide an additional eight or more inches of travel in an MA by eliminating a carabiner and replacing a Figure 8 on a bight.
The strengths of poacher’s and scaffold knots vary depending on rope fibers, construction and diameter. They are generally more efficient on 100% Nylon sheath/core ropes as opposed to 100% Polyester sheath/core ropes. Previous testing as shown up to 78% efficiency on ½” 100% Nylon ropes as compared to 69% efficiency on ½” 100% Polyester ropes. A safe number to use on other rope fiber combinations and diameters would be 50%. All of these figures are for Kernmantle Life Safety Rope.
A question that commonly comes up once the rescuer understands the difference between a scaffold and poacher’s knot is which knot should be used. Again, differences in rope fibers and diameters will give varying results. Another factor to consider is how hard will it be to untie the knot once it has been loaded. This is more subjective to test, but in most cases the scaffold knot is slightly easier to untie. When either knot is tied on a carabiner a significant advantage exists. Once load has been removed and the rope is out of the system, the carabiner will function as a crush carabiner when the loop is slid off the open end of the device after the gate is opened.
The CMC Rescue School prefers the scaffold knot as opposed to the poacher’s knot due to the slight advantages discussed above.