What is the efficiency rating of a knot that chokes?

The efficiency rating of a knot that chokes is generally recognized to be around 50%. This rating reflects the loss of strength that occurs when a rope forms a knot, particularly a choking knot, which causes the rope to bear a significant amount of friction and bend. When a knot chokes, the load is typically concentrated on a smaller surface area, increasing wear and reducing the overall capacity of the rope to handle weight.

In rigging and other applications, understanding knots' efficiency ratings is crucial as they directly impact the safety and reliability of a lift or secured load. A 50% efficiency means that the knot retains only half of the rope's original tensile strength, which highlights why careful consideration should be given to the type of knots used based on the specific rigging application.

Higher efficiency ratings, such as those mentioned in the other options, do not apply to choking knots, as they typically introduce significant compromise in strength due to the nature of how they grip and bind.