Usage
The Poldo Tackle is a highly versatile, adjustable tensioning system designed for rapid tightening or loosening. It utilizes two fixed loops, such bowlines (shown here) or figure-eight loops, offering numerous possibilities for any situation necessitating a tensioning apparatus. Suitable applications for this knot include a clothesline or guyline, and it is particularly beneficial in situations that intermittently require releasing or tensioning a loaded line. Its standout feature is its ability for swift adjustments: reducing tension is achieved by drawing the two fixed loops together, while increasing tension necessitates pulling them apart.
Warning
Verify tying technique with a skilled instructor where knot failure could cause property damage, injury, or death.
History
The Poldo Tackle system owes its name to Poldo Izzo, an 18th-century sailing instructor from Caprera, an island in the Maddalena archipelago located off Sardinia's coast in Italy. Its first depiction and description surfaced in the groundbreaking French Encyclopédie in 1751 and was listed under the french name "nœud à crémaillère" (Thanks to the IGKT forum). This encyclopedia stands out in history as the first comprehensive reference work to enlist contributions from numerous acknowledged contributors and was the first general encyclopedia to describe the mechanical arts including knot tying.
Structure
The Poldo Tackle functions in many ways like a rope and pulley system. The fixed loops act as the pulleys. Friction can be reduced by introducing carabiner's at the fixed loops and letting the adjustable part of the rope pass through the carabiners instead.
Strength/Reliability
The Poldo Tackle is best used with static loads as unexpected shifts in dynamic loads could trigger an abrupt, unanticipated release of the system. The Poldo Tackle provides a theoretical mechanical advantage of 2:1. Actual mechanical advantage is less and varies due to friction. Carabiners instead of fixed loops in the rope can reduce the friction in the system and increase the actual mechanical advantage.
