The Stone knot, also called a Stein knot, is a blocking knot used to isolate two strands of rope so that both may be rappelled on independently. Since a Stone knot requires an object for completion, it is in the class of knots known as hitches.
How to tie
- Take a bight of the two strands of rope looped over an anchor ring
- Make a half-twist in that bight of rope (a loop or half-turn)
- Rotate the half-twisted bight of rope up toward the anchor onto the two strands of rope
- Pull the two strands of rope through the loop formed by the half twist
- Insert a carabiner in front of the loop but behind the two strands of rope
- Clip the carabiner to one of the two strands above the loop and lock the gate
The stone knot isolates both strands making it possible to rig and rappel on either or both strands. This allows one person to rig for rappel on one strand while another person is rappelling on the other strand, and thus eliminates rigging time for everyone but the first and last rappellers which are generally the most competent members of the group.
- Rig a standard double-strand rappel from an anchor ring ensuring the both ends reach the ground
- Add a stone knot below the anchor ring to isolate both rope strands
- Two people begin rigging for rappel using one strand per person and the first person to finish begins rappelling
- When the first rappeller is off rappel, the second person begins rappelling immediately because he has already finished rigging while the first person was rappelling
- A third person begins rigging on the first rope strand as the second person rappels
- Repeat until all but LAPAR have finished rappelling
- LAPAR removes the carabiner used in the stone knot and rappels double-stranded
- Retrieve the rope normally
The most common twist is a half twist of the bight that forms the stone knot, but a full twist can be used to form the figure 8 variation of the Stone knot. The figure 8 variation was the original version of the knot.
After making a twist with the bight of double rope, the twist may be rotated upward toward the anchor or downward toward the bottom of the drop. The upward method is preferable because of its superior release characteristics.
The last step of constructing the Stone knot is to clip the carabiner around one of the two strands of rope above the loop so that the loop cannot be pulled around the carabiner during rigging activities. This cannot happen while the Stone knot is weighted. If neither of the strands is clipped, the hitch formed might be dangerous because movement during rigging may cause the hitch to fall apart entirely. If both strands are clipped, this forms a secured hitch, but it is more difficult to differentiate between that hitch and the unsecured hitch formed when neither strand is clipped. Clipping one strand forms a correct secured Stone knot.
If the last construction step is not completed, it is possible for the twisted loop to work its way around the carabiner when jostled during rigging. If this happens, the hitch will fall apart and both of the strands will become unsecured.
If the Stone knot is not dressed properly by snugging the knot down against the carabiner, the loop may expand over the carabiner causing cross-loading on the gate, which will cause the carabiner to fail at much lower loads than normal.
If the carabiner gate is unlocked and the carabiner is then cross loaded as above, the hitch will release and fall apart entirely.