Many folks think a rope is such a simple thing. It is deceptively, seductively so. Actually, ropework is an incredibly deep art form and can be a way of life.
Rope manufacturers are very concious of arborist rope slippage. They recognize how bombproof a rope must be to put up with our brutal treatment.
Because of the radius difference and the braids reversing themselves back & forth in the weave, the sheath stretches more then the relatively parallel core. The rope manufacturing process puts incredible tension on the strands to minimize this stretch during construction. When I had a Blue Streak eye spliced in Seattle, I was told that the rope design had been modified to unify the core & sheath, and lessen this tendency. It used to be very milky rope early on in it's design life. I wish I could get more info on the process of design evolution.
Todays climbing lines are an incredible advancement in technology that make our lives a lot easier. The gift of the miracle materials we have been handed make the natural fiber lines of yore seem like inquisition torture devices. The number of stories of catastrophic line failure instances is much rarer, now. My own score is: Falls from treacherous manila-2; Falls from synthetic-0. Yet, the development cycle has only been possible by a responsive cordage industry. Thanks, guys. It's a good thing climbers are patient and hard-headed.
The use of different color lines is a good illustration of the fact that we live in the 21st century. A climber involved in complex rigging situations can become oriented at a glance, due to the color coding of the different lines. Communication with ground support is greatly simplified. Merely by indicating the color of the line, treeworkers can be trained in the function & usage of a particular rope. Multiple climbers are safe in the knowledge that their particular line is sacrosanct by this distinct visual identification.
Different lines have different handling characteristics, which can be a burden to sort out. Being professional, we're expected to be familiar with all of the qualities of the tools we elect to use. This isn't Kansas, anymore, Toto! Know the diameter, loadhandling capacity and tackiness for running thru different friction devices & knots. For example, some mountaineering devices have low tolerance for excessive diameter line.
Above all, know the lengths of the several lines you will be using. Don't get so lost in the intricacies that you forget how short a line is, and run off the end of it!
Get to know your lines intimately, for they are your friends. Force yourself to go thru the formality of an introduction. Establish a relationship by reading the product information that comes with a new line, for you are becoming aquainted with a new partner. Don't ever step on a climbing line. Would you step on your friend? Take care of your tools and they will keep giving back to you.
Just make sure to carefully break in the rope when new. Mount the spool on a spindle, such as a rake handle, and roll it off the spool to prevent twisting. If a rope is coiled, make sure it is put up and flaked out from the proper end. Did you know that the two ends are not identical, they are mirror images of each other? Only the sheath is symmetrical. The core has a twist in one direction only. This is the personality, part of the hand (feel) of the line.
Melt one end, if it is not eye-spliced, and use that end only for a few trees. Run the climbing hitch all the way out to the end, and off of the line. Don't melt the end until some of the glaze has worn away. Beware of the changing properties a rope will metamorphize thru while the slickness wears away! Another practice to avoid during break-in is rapelling down from both ends in a double tie-in situation, which will bunch up line in the center.
Bag your climbing lines, for coiling them can introduce kinks. Coiled ropes seem to get laid on the ground, which introduces dirt in between the fibers, and cuts them. This is what causes a rope to become limp with age. A bag also protects it from harmful sunlight, and keeps gasoline & oil drops, etc. away, which breaks down the ropes strength.
Don't wear gloves when bagging lines. Train yourself to go thru a ritual of removing your gloves before you put the line away. Feel the line as it slides through your fingers, for this is the best time to inspect it (a daily ANSI requirement).
Check for swelling or skinny spots, picked strands, long black melt marks, etc. Correlate these bits of damage to the activity that created them while the memory of what occurred is fresh in your mind. Then, you can modify your practices (which is called training) to prevent abuse in the future.
Here's a couple places to start when looking at product info.
samson
New England Ropes
Try it and see.
