Bowline

The bowline is a simple, ancient knot that creates a fixed loop at a rope's end. It is valued for being easy to tie and untie, especially after it has been under a heavy load. Often called the "king of the knots" due to its importance, it is considered one of the most essential knots, alongside the sheet bend and the clove hitch. The common bowline shares structural similarities with the sheet bend; nearly every bend used to join two rope ends has a corresponding loop knot.

While generally reliable, the bowline has drawbacks: it can loosen when not under load or under repeated loading, slip when pulled sideways, and its bight can capsize in certain situations. To fix these issues, more secure variations have been created for safety-critical uses, or the knot can be backed up with an overhand knot.

**History**

The name "bowline" dates back to the Age of Sail. On a square-rigged ship, a bowline (sometimes written as "bow line") is a rope that holds a square sail's edge toward the bow and into the wind, preventing it from being taken aback. A ship is said to be on a "taut bowline" when these lines are pulled as tight as possible to sail close-hauled. The knot is thought to have been first mentioned in John Smith's 1627 work *A Sea Grammar* as the "Boling knot." Smith considered it strong and secure, noting that the rope or sail would break before the knot slipped. Another possible finding was discovered on the rigging of the Ancient Egyptian Pharaoh Khufu's solar ship (26th century B.C.) during a 1954 excavation.

**Usage**

The bowline makes a loop at one end of a line, tied with the rope's working end (the "tail" or "end"). The loop can pass around or through an object while tying, and the knot tightens when the standing part of the line is pulled. It is commonly used in sailing small craft—for example, to fasten a halyard to a sail's head or tie a jib sheet to a jib's clew. The bowline is also well known as a rescue knot for pulling people from holes or off cliff ledges, as it can be tied with one hand. A person needing rescue can hold the rope with one hand and tie the knot around their waist with the other. The Federal Aviation Administration recommends the bowline for tying down light aircraft. A rope with a bowline retains about two-thirds of its strength, though the exact amount varies depending on the rope's nature and other factors. In the United Kingdom, the knot is part of the training objectives for the Qualified Firefighter Assessment.

**Security**

Several more secure variants address the bowline's shortcomings:

- **Round turn bowline:** Adds an extra turn in the "rabbit hole" before the working end is threaded through. - **Water bowline:** Forms a clove hitch before the working end is threaded through. It is stronger and more resistant to jamming, especially when wet. - **Yosemite bowline:** The working end goes around the loop in the direction of the original round turn, then threads back up through that turn before tightening. It is often used in climbing.

**Other variants**

The cowboy bowline (also called Dutch bowline), French bowline, and Portuguese bowline each make one loop. A running bowline creates a noose that tightens under tension on the standing part. The Birmingham bowline has two loops, with the working part passing twice around the standing part. Other two-loop bowlines include the Spanish bowline and the bowline on the bight, which can be tied in the middle of a rope. A triple bowline makes three loops. An Eskimo bowline or Cossack knot has the running end go around the loop-start rather than the main part, forming a more symmetric triangular shape. A slipped version of the Cossack knot is called the Kalmyk loop.