Rescue Knots, Hitches, and Bends

Rescue Knots, Hitches, and Bends
Vertical rope work demands a skilled rigger. The rigger ties off the ropes and pads, and weighs the advantages and disadvantages of one tie-off point over others. Securing rope is a critical skill that should be mastered by all vertical cavers, climbers, and rope users.

After the rope has been attached to it's anchor by the rigger, it should be closely examined by each member of the party before use. After all, it is a critical link upon which lives will depend.

A skillful rigger does not need a vast repertoire of knots or ties. In fact, some say that knowing a Bowline and a Figure Eight , and all their variations, can accomplish all the needs in rope work. Knowing a few ties and knowing them well is far better than being familiar with dozens of ties about which one feels only vaguely comfortable.

Ties are essential to a successful rigging. They should be as simple to untie as they are to tie, should not be able to work themselves loose, and should be simple, allowing for easy inspection.

The size of the tie is a factor that sometimes becomes an important criterion in selection. A compact tie may be necessary if it has to travel through a pulley or if it becomes necessary to climb or rappel over it.

A rope's fibers undergo stress whenever they are bent or twisted. As a general rule, a rope oriented in a straight line will maintain the greatest original strength. Therefor, the sharper the angle at which a rope is bent, the weaker it becomes at that point.

Research has shown that ropes really don't break in the tight bends of a tie, rather, ropes and webbing break at a point going into a tie. At this point the tie loops bind down on the incoming rope or webbing and pinch them off to the point of failure. Even a Prusik Hitch under great tension, pinches a rope so tightly that it actually melts the main rope apart.

Tie Efficiency
Tie efficiency or the remaining relative strength of a rope after a tie has been placed is a debated topic and varies with the rope type, diameter, and source of one's data. A tie should be selected because of what it can accomplish. Exam all the options at your command while taking into consideration the approximate strength loss.

Sometimes tie efficiency may be sacrificed for the priority of "compactness." These tie trade-offs are the rigger's responsibility.

Finishing
Finishing a tie involves two activities:

Dressing
Setting

Dressing
Dressing a tie involves the orientation of all the parts so that they are all properly aligned, straightened, or bundled. Take a few minutes and carefully align tie parts. Be sure intended parallel components are parallel as it's the friction between a tie's created turns that gives it holding stability.

Setting
Setting a tie involves tightening all parts of the tie so that all of the rope parts touch, grab, and cause friction upon other parts of the tie so as to render it secure. A loosely secured tie can easily deform under force and change in character. For instance, to set a Bowline effectively, requires tension in three directions at the same time especially with soft rope.

Common Tie Securing Terms

Tie - A generic term encompassing all the general categories of securing cordage, including: hitches, bends, and knots.

Knot - A fixed, non-movable place on a piece of cordage that is achieved through turns, bends, and tie-offs.

Hitch - A group of ties that wrap or attach to other objects or ropes. Almost always, when the object is removed, the tie will fall apart.

Bend - A tie that unites two rope ends.

Bight - A doubled section of rope, usually taken from the center of the rope, that does not cross itself.

loop - A turn of the rope that crosses itself.

Running End The end that is not rigged or the free end

Standing Part of the Rope - All of the rope that is not fastened at the rigging point

The Working End - The end that is used to rig with or tie off to something.
Tie Characteristics
There are at least six critical characteristics that determine a tie's value:

Strength
Ease of Tying
Ease of Inspection
Ease of Untying
Versality
Compactness
Categories of Ties
A majority of rigging/sling tie sources classify ties into four major categories:
- Anchors
- Mid-line riggings
- Bends
- Friction, belay and climbing hitches
  The first two categories are truly knots that, when secured, should not move or slide. These lend themselves to main riggings. The bends (end-to-end tie-offs) have mostly sling applications, while friction, belay ties, and climbing hitches all have interchangeable applications.
  Anchors
  The Bowline is a multi-purpose knot that is as easily untied as tied. Its loop is easily adjusted. It has a high efficiency rating, but has been known to work loose during repeated loadings, especially with softer rope.
  The end of the rope should be oriented on the inside of the major loop, not on the outside. On the outside of the loop, the send is vulnerable to snagging. This is one knot that must be dressed and set. If left loose, it can distort and fall apart.
  
  Figure Eight
  The Figure Eight has many purposes and variations. It is the basic necessary knot that forms the Figure Eight on a Bight, Figure Eight Bend, Double Figure Eight, and the In-line Figure Eight.
  By itself it is often used as a stopper so a rappeller or piece of gear won't slide past the knotted point.
  Figure Eight on a Bight
  By forming a bight near the end of the rope, an easy, reliable non-slipping loop can be formed for hauling, life support or gear lifting. The Figure Eight on a Bight has numerous applications, including carabiner clip-ins, mid-line riggings, and reanchors, just to name a few.
  It is the preferred end-line safety knot because it supplies a loop to stand in at the end of the rope that could assist a climber during an attempt to change-over from rappel to ascend.
  
  Figure Eight Follow Through
  The Figure Eight Follow Through can be used as a primary end-line rigging around an anchor, such as a tree. First, tie a simple Figure Eight, loop the end around the anchor and rethread the end back into the knot, following it backwards. Do not forget to dress and set it when finished.
  The loop formed should be only large enough to contain what is intended to be placed or clipped into it.
  
  In-Line Figure Eight
  The In-Line Figure Eight is a directional knot and when it is running or sliding, trips trough pulleys easier and over tree limbs more easily. If back-up rigging is employed, an In-line Figure Eight makes an easily adjustable first knot.
  
  Butterfly
  The Butterfly is a compact, mid-line knot, useful in many situations. Its important feature is that it provides for multi-directional loading. It's important to dress and set this knot, and seems to work best with softer ropes.
  
  Bends
  Figure Eight Bend
  The Figure Eight bend is a variation of the Figure Eight knot. It is best used when it is necessary to join two ropes together. It is somewhat bulky, but will slide through the larger knot-passing rescue pulleys. It is easy to tie as well as untie. It is visually obvious when tied incorrectly.
  This knot requires dressing and setting. In webbing, it is not so obvious when tied incorrectly. Also in webbing, it is about 50% stronger than a water knot,although it is occasionally discouraged because it is difficult to dress and set.
  
  Water Bend
  This is probably one of the most used bends. It is excellent for fastening webbing together, such as in directional rigging. The drawback is that it can be very difficult to untie in webbing, as well as rope, after heavy loading. Rolling it vigorously between the palms of the hand can help loosen it.
  
  Double Overhand Bend
  TheDouble Overhand bendis a good bend to use to form endless loops of rope. It is compact and is often used when fashioning Prusik slings.
  
  Sheet Bend
  The Sheet bend is for tying two pieces of rope of different diameter together.
  
  Prusik Hitch
  The Prusik hitch is primarily a gripping friction tie and the one most often referred to when speaking of a friction tie. A rope, cord, or sling is wrapped around the main climbing rope in such a way that the Prusik cord grips the main rope and will not slide under tension.
  Prusik cords need to be of semi supple rope. If the rope is too soft or too small in diameter, they tend to dig deep into the mainline, gripping it tightly. When it comes time to slid the knot, it becomes most difficult to break.
  On the other hand, stiff rope makes terrible Prusik cords because it resists bending and knotting.
  When there is no tension on the hitch, it slides freely up or down. The Prusik hitch is mentioned here because it is one of the most critical ties to learn.
  
  Clove Hitch
  A clove hitch can be useful for tying around objects for hoisting, or as anchor.
  
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