ROPE:

Two broad catagories:

    Natural fiber and Synthetic

Natural fiber;
Made from plants, easily made by hand, but affected by moisure and humidity, 
and rots easily.
	* Manila:
        leave stalks of the abaca. Twisted. Hard on the hands.
	* Hemp:
        stems of hemp plant, not legal in this country. Twisted consruction.
	* Sisal:
        leaves of Mexican Agave, not as strong as hemp. Common binder twine. 
        Twisted. Better hand than manila.
	* Cotton:
        very weak, rots quickly, but very soft and holds a knot well. 
        Braided. Excellent hand.

Synthetics
Have mostly replaced natural fibers, much stronger, doesn't rot from moisture.
	* Nylon:
        first and strongest of common pertoleum plastics used for fiber. 
        Very strong but very stretchy. Deteriorates under UV. 
        Slippery, needs special attention w/ knots. Good hand.
	* Polyesther:
        a.k.a. Dacron. Nearly as strong as nylon, somewhat heavier. 
        Very little stretch, not quite as slippery as nylon and holds knots better. 
        Good hand. Best replacement for manila in most theatre situations.
	* Polypropylene, polyolefin:
        lighter, cheaper, but weaker than nylon or dacron. 
        Tends to be stiffer and slipperier. Not as good a hand. Floats.
	* Polyethylene:
        light, cheap, weaker and stiffer than other synthetics, but fairly 
        immune to UV. Poor hand, floats. Common as hollow braided water skiing 
        rope.
	* Kevlar:
        fairly new, very strong, but stiff and brittle. 
        Expensive and slippery, almost no stretch. Poor knot holding and poor 
        hand. Hardly ever used in theatre.

Construction:
TWISTED most commonly used for traditional natural fibers that take a set.
	* Fibers twisted into YARNS.
	* Yarn twisted into STRANDS.
	* Strands twisted into LAYS.
        Typical pattern: 3-strand lay. Four stand also possible.

Can be hand made, but usually machine made.
BRAIDED, most common for softer fibers that don't take a set well, 
cotton and most synthetics.
   • Multiple strands braided into BRAIDS.
	* Three strand: Produces flat rope, easiest hand braid but otherwise 
        not used.
	* Four strand braid and up (e.g. 8-strand, 12 strand, ect.): 
        Produces round rope, much more typical, almost always machine made.
   Produces a cylindar of rope, a tube of fiber with a hollow core.

Three typical patterns:

Hollow braid:

Hollow core is left unfilled; very flexible rope. 
Very easy to splice or to pass a fid through without damage. 
Ex. water skiing rope.

Ideal for synthetic purchase line on counterweight system. 
Trim ribbon may be inserted without damaging rope.

Kernmantle ropes:

Braided rope around a core material.
•    Kern is Austrian for core.
•    Mantle for sheath.
Together, "a Sheath around a Core".

Two forms of kernmantle:

Single-braid:

Braided mantle around a core of parellel fibers. 
Core may just be filler, but often adds greatly to strength of rope, 
depending on material used.

Most common contruction for synthetics. Subject to some "milking" depending 
on stretch of core vs. mantle.

Most common general-purpose synthetic rope.

Double braid:
Literally, a braided mantle around a braided core, a rope within a rope.
	* Often found in climbing rope.
	* More abraision resistant than other constructions, 
        core is protected by hard-braided mantle.

Often stiffer than single braid, harder hand, great tendancy to "milk".

Most often found as rigging rope, i.e. what "up-riggers" lower to floor as 
workline when installing temporary rigging.
   Designed to go with rock climbing equipment often used as rigging gear.

Material strength:

Based on SWL; ultimate break strength is at least 5x's SWL
Fiber          Rope Diameters
            3/8"  1/2"  3/4"  1"	
Natural
Manila      200   440   1080  1880
Sisal	150   350   865   1440

Synthetics
Nylon       400   780   2000  3600
Dacron      390   745   1870  3220
Polypro     300   600   1600  2800