dynamic and static and semi-statich

[Ropey]

This is the old "Kernmantle" debate. The rock climbing fraternity have evolved this term over the years to refer to a braided cover (Mantle) over a bunched parallel core (Kern) like the Donaghys NRG or the NE Fly and most Dynamic climbing ropes.

 

This however is not totally correct. Moby has the correct definition in 'a textile rope consisting of a core enclosed by a sheath' the key here is the core which can be braided, parallel or stranded.

 

So believe it or not the term Kernmantle rope covers all the braids apart from a solid braid.

 

It would loosely cover the likes of the 16 plait constructions as these have a Kern of fibres to keep the braid round but these fibres do not carry the load so you could argue both ways here.

 

The ropes used in the Arb industry are specialist ropes designed for this purpose and are quite different from “work from height” ropes.

 

Arb ropes have elastic Elongation ranging in the range of 2% - 6% approx.

 

You tend to get around 3% just with the braiding of the fibres then the fibre elongation as well but this can be reduced by heat setting the ropes once made.

 

If the rope is too stretchy (Dynamic) then you use to much energy climbing up them, not enough and it makes it hard to position around trees. “This is a personal thing.”

 

I hope this helps or not……….

[xdarkknight]

I think this question has been answered pretty damn sufficiently, but...

I'll toss this in.

You climb up a static rope using ascenders and such and are lowered from the anchor point or using a controlled descent or belay (abseil) device. This method is used in Tree Climbing where isolating a line is difficult to nigh impossible (and in 6.Aid Mountain Climbing/ Mountain or Climbing Rescue).

You never want to take a big fall against a static line. It's like falling against a stair-rail, except the stair rail is your saddle.

Dynamic ropes are almost entirely used in rock climbing. They stretch to take up the energy produced in a long fall. They are also very "slippery", water resistant (ie: "dry rope"), though not as abrasion resistant to constant rubbing (like in a tree crotch).

Semi-static ropes are necessary for tree work. materials used are much more abrasion resistant than rock climbing lines, while maintaining the flexibility and energy dispelling qualities of them. They also maintain the user in place in the tree in the way a static line would.

 

Also, many knots have difficulty staying in a very dynamic line. Many Rock-Climbers (that I've known) use only 2-3 knots in their climbing line. Also, you can't use a climbing hitch (prussic/vt, etc) for very long on a dynamic line as it will glaze the rope.