Which knot passes through a knot pass pulley easier?

The double fisherman's knot, while commonly used to join two lengths of rope like in climbing or fishing contexts, is less suited for passing through a knot pass pulley. This knot creates a very tight and compact structure that, once tied, may have difficulty sliding smoothly through narrow spaces like pulleys or other mechanical devices designed to manage rope.

The bowline knot is specifically advantageous for passing through a pulley because it forms a fixed loop at the end of the rope, ensuring that the knot won't jam but rather maintains its shape as it passes through the pulley. It is designed to provide ease of movement while still securing the load effectively.

In contrast, the figure 8 knot is stable and secure but can also create friction points when navigating through narrow pulleys. Its bulkiness might lead to issues with smooth passage. The square knot is primarily used for securing two ropes together and lacks the structural design that facilitates easy passage through mechanical devices.

Ultimately, the bowline knot stands out for its ability to pass smoothly through a knot pass pulley, making it the best choice for that particular application.