Which of the following knots has an efficiency rating of 60%?

The square knot is known for its specific efficiency rating of approximately 60%. This rating reflects the knot's ability to hold and secure two ends of rope together. While the square knot is commonly used for binding or joining two lines of similar diameter, its efficiency can be affected by the type of material and the load being applied. When the knot is under tension, it can become unstable and may slip, which is a significant reason for its lower efficiency rating compared to other knots that are designed for greater load-bearing capacity.

In contrast, both the back splice and the eye splice are designed for terminating the ends of rope and have higher efficiency ratings. The short splice is another method for joining ropes, typically used in situations where a more secure and efficient connection is needed, surpassing the square knot's performance. This contextual understanding helps clarify why the square knot, while useful, has a lower efficiency rating, making it less suitable for high-stress applications compared to other knot types.