What type of knot is used for tying together two dry ropes of the same size?

The square knot is specifically designed for joining two ropes of the same size together. It creates a secure, flat knot that lies relatively neatly, making it easy to untie even after bearing weight. The reliability of a square knot comes from the way the two ends of the ropes interweave, allowing them to be pulled together tightly, which is advantageous in various rigging applications.

When using a square knot, it is essential that both ropes are of the same diameter for the knot to hold securely and function as intended. This knot is commonly used in practices where the two lines being tied together are to remain aligned and not slip.

In contrast, the other options serve different purposes or are designed for different scenarios. The figure eight knot is often used as a stopper knot or for securing climbing gear rather than joining two ropes. A half hitch is typically used in conjunction with other knots and does not secure two ropes together by itself. The sheet bend is ideal for joining ropes of different sizes, making it unsuitable for the specific requirement of tying together two ropes of the same size.