The Yosemite, or Tucked Bowline. A Tucked, sometimes called, Yosemite bowline, is a loop knot often perceived as having better security than a bowline. It has been pointed out that if the knot is not dressed correctly it can potentially collapse into a noose, however testing reveals this alternative configuration to be strong and safe as a climbing tie-in.
A Yosemite bowline is made from a bowline with the free end wrapped around one leg of the loop and tucked back through the knot, a final round turn and reeve commonly known as a "Yosemite finish." The knot's security is enhanced by preventing the bowline "capsizing" to form a highly dangerous slip-knot. Additional safety is achieved by tying with a tail. When finished, the working end forms a figure eight.
Because of the danger of incorrectly tying the yosemite bowline, it may be safer and less error-prone to use a standard or double bowline with a backup stopper knot added to the tail, such as a double overhand knot tied around the loop.
The Yosemite finish can be applied to other bowline variants, such as the double bowline.
While the knot's versatility suggests it as a convenient tie-in for attaching a climbing rope to a climber's harness, the figure-of-eight follow through is the most common choice because it is more widely known and perhaps more easily checked. The Mountaineering Handbook is one of the few texts that suggest that the Yosemite bowline is better for this purpose. Suggested benefits of the bowline include being easier to untie after loading or when wet and frozen, and being possible to tie-in with only one hand. Testing found it a strong knot for the purpose.
It is recommended that any knot which is used to attach a rope to a safety harness is always finished with a "stopper" knot. A stopper knot, while serving to keep the loose end tidy, will not only help to prevent failure of the primary knot, but also act as a secondary safety knot itself. It is sometimes said that if enough of a tail is left to tie a stopper knot, the stopper becomes unnecessary. The tail should be a minimum of 40 – 60 cm depending on the thickness of the rope.