Which knot is known for its ability to hold well under load but untie easily after use?

The Bowline knot is recognized for its unique combination of being secure under load while also being easy to untie after being loaded. This feature makes it exceptionally useful in various rescue and climbing scenarios where a reliable attachment point is necessary but may need to be released quickly after use.

The construction of the Bowline creates a fixed loop at the end of the rope, which maintains its integrity under tension without jamming, allowing for easy untying even after being subjected to heavy load. This contrasts with knots like the Prusik knot, which is designed to grip the rope when weight is applied and can be difficult to untie afterward. Similarly, the Figure 8 knot is generally secure but can become tighter under stress, making it more challenging to untie. Lastly, the Double Fisherman's knot is primarily intended for joining two pieces of rope, and while it holds well, it can be tough to untie after being pulled taut.

Thus, the Bowline is the knot of choice when the need for both security and ease of untie is paramount, making it a favored option in many rescue and climbing applications.