Bowline on a bight

In an ordinary bowline the end passes through a small loop, around the standing part and back again – the small loop holds the end like a clamp. In the bowline on a bight the same thing happens with doubled rope. The difference lies in the last step: instead of taking the end around the standing part, you open out the bight and slip it over the two large loops. Afterwards it lies around the back of the standing parts and closes the knot.

Under load the small loop presses the bight against the standing parts. The load is shared between two loops, each carrying only part of it. Because none of the turns is bent very tightly, the knot is usually easy to open again after loading – an advantage it shares with the ordinary bowline.

A neatly tied bowline on a bight looks tidy and symmetrical. The two strands run side by side throughout without crossing each other inside the knot – this is called “dressing” the knot. The bight lies completely behind the knot around both standing parts, not halfway over one of the loops. From the front you can see the typical bowline shape: a small loop with two strands running through it.

To “set” the knot, pull alternately on both loops and on the standing parts until everything sits firm and compact. A loose knot can change shape before it is even loaded. Then check: can the loops be shifted against each other? With this knot that is possible and normal if you deliberately pull on one loop – which is why you should load both loops as evenly as possible. There is no loose tail in the usual sense here; instead the bight must lie fully around.

The most common mistake is slipping the bight only partly over the loops. It then sits in the wrong place, and when you set it the knot slides apart or deforms into something undefined. A second classic mistake: the small loop is formed the wrong way round. The knot looks almost right at first but falls apart when you pull it tight.

Even a correctly tied bowline on a bight has limits. If the two loops are pulled apart against each other, rather than downwards together, rope can creep from one loop into the other. And as with the ordinary bowline, a knot that is unloaded and moved about a lot can work loose. So check it before you load it again.

In camp the knot is handy when a load should hang from two points, for example a bag on two hooks, or when you need a fixed loop in the middle of a line without reaching an end. The two loops together also give a wide bearing surface that cuts in less than a single thin loop.

It is less suitable when you only need a simple loop in the middle of the rope – an alpine butterfly or figure-eight loop is easier to remember and mistakes are easier to see. It uses a lot of rope and is hard for beginners to remember. This page is expressly not about lifting or securing people with it.

The emergency-seat story is the reason this knot is sometimes overrated. Life-safety use only after proper training with certified equipment – that is also where people learn how to check knots under real load and which equipment is approved for it. In everyday use: do not hang anything with this knot over people, and do not lift anything with it that could injure someone if it fails.

For practice, a soft, medium-thick rope in which you can see the strands clearly works well. First learn the ordinary bowline properly, then the bowline on a bight. Tie it several times in a row, set it, open it again and compare the shape every time. When you can tie it with your eyes closed and still spot every mistake when you look, you really know it.