What is the best knot to use for joining two ropes of equal diameter?

The square knot is specifically designed for joining two ropes of equal diameter. It provides a secure and flat tie, which ensures that the two ends of the ropes are held firmly together without slipping. The structure of the square knot consists of two identical half knots that are tied in opposite directions, making it easy to untie after use, which is especially beneficial in situations where you may need to release the ropes quickly.

In contrast, while other options may have their own applications, they are not as effective for joining two equal-diameter ropes. The sheet bend is best suited for joining ropes of unequal diameters, as it offers a secure hold when the ropes are of different thicknesses. The bowline creates a fixed loop at the end of a rope but does not actually join two ropes together. Lastly, the double clove hitch is typically used for tying a rope around an object rather than for securely tying two ropes together. Thus, the square knot stands out as the most practical and effective choice for this specific scenario.