Yes, there is much confusion here. Kern means core, mantle means jacket (German). This construction was originally designed by Edelweiss in the 60's (I think) to improve the safety of mountaineering ropes from rock abrasion - The jacket is designed to protect the core of load bearing fibres.
12 strand single or hollow braid was used by arborists in the USA originally over 3 ply because it was light, low stretch, didn't twist and would knot easily with a taut - line hitch (dynamic kernmantle is too stretchy but would hold a tautline, low stretch kernmantle wouldn't hold a tautline). 16 strand hollow braid, was designed not to flatten like the 12 strands and have a smoother surface. It therefore has a core to keep a round cross section to aid knotted strength, but the strength is in the sheath. It is sometimes called kernmantle, but it isn't.
Hollow braid is a term generally reserved for the type of loose contruction used in products with easy adjust friction splices like whoopie/loopie slings and cobra type bracing rope. I don't like it for friction hitches as it has no core as back up from melted fibres. In fact, I think it has too many drawbacks that pretty much exclude it from PPE. Other construction types do a better safer job.
Double braids have a load bearing sheath and core. They are heavy, soft, and flatten. The Fly is a true kernmantle with a thicker than normal sheath, and a good round cross section.It runs nicely through 11mm devices and is light weight. A great all rounder for the climbing Arborist. Also makes great split tails for Blake's hitch, and safer, because the load bearing fibres are protected by a thick sheath. The Blaze is a double braid that flattens. I prefer the Fly as it has greater protection from abrasion and UV, and is easier to grip (ergonomics)with a round cross section. Also knots nicely, and has a little bounce - another safety consideration after you realise the forces that can occur in some situations (like that little peg breaking just above the anchor branch you thought you were on!).
Problems arise when deciding upon application and making important decisions during inspection - where are the load bearing fibres? How many could be damaged before relegation or retirement?
Double braids aren't best used for climbing or natural crotch rigging, as the sheath /core slippage can reduce strength as they slip against each other. They can also milk easily with a prusik, which can also loosen a splice if run to one end, which happened to a good mate of mine who fell 35 feet on the second day of useage when the splice pulled through because he rotated ends. I'm not sure how the Blaze differs from other double braids not to worry about this? I think some Arborists obsess a little too much about low stretch and splicability, at cost to other important considerations!
Many manufacturers without a rock climbing pedigree, tend to call any ropes with core and sheath a 'kernmantle' - irrespective of where the strength is, or origins and import of the term.
Enough, time to get some paid work done! /forum/images/graemlins/crazy.gif
Standard setting on nomenclature between rope manufacturers would be nice!
