What type of knot is typically used to create a secure loop at the end of a line?

The bowline knot is used to create a secure loop at the end of a line, making it an ideal choice in various rigging scenarios. This knot is particularly valued for its strength and the fact that it can be easily untied after being loaded, which is essential for safety and efficiency in theatre rigging. The bowline forms a fixed loop that does not slip, ensuring that whatever is attached to it, whether it be a rope, a harness, or a retrieval device, remains secure under tension.

While the figure-eight knot is also commonly used in rigging to create a strong loop or as a stopper knot, it is not as effective for forming a secure loop at the end of a line compared to the bowline. The clove hitch is primarily used for securing a rope to a post or another solid object but does not create a fixed loop at the end of a line. The sheet bend is useful for joining two different ropes together, particularly if they are of unequal size, but again, it does not create a loop at the end of a single line. Thus, the bowline knot stands out as the correct answer for forming a secure loop.