Abrasion is throwbag ropes` biggest enemy. No floating rope construction have good resistance against friction.
Polypropilene has a low, 160 Celsius melting point. If a rope is tensioned, energy transforms into heat. A bit of friction on a rock and your rope snaps. Bumm...
Sharp rock effects expensive ropes the same way. Spectra and Syntec ropes are getting damaged as well due to the cover having the same material.
See some videos of our basic Abrasion test:
How many seconds do you guess it takes to break a throwbag rope?
See chart of tested ropes:
(how many seconds the rope last if we apply friction by an other rope)
Type cover Core diameter broken in
Coreless PP coreless 8mm 3 sec
Flat kernmantel PP PP 8mm 5 sec
Doublebraided PP PP 8mm 10 sec
Syntec/Spectra PP PP+Dyneema 8mm 10 sec
Kernmantel PP PP 10mm 11 sec
Floating Rescue PP Nylon 8mm 60+ sec (not broken)
WWTC PP PP+Polyester 8mm 60+ sec (not broken)
WWTC PP PP+Polyester 10mm 60+ sec (not broken)
Conclusion (for whitewater rescue):
- The cover gets damaged anyways by abrasion (breaks in 3 sec)
You can not avoid using Polypropilene as you need the rope to float
- to use Nylon/Poliester in the core makes you better resistance against abrasion though the cover gets damaged anyways.
The difference is that you can finish the rescue and your rope does not break, after abrasion damage your rope is garbage either ways. So try to avoid rocks...
Also it is sensitive on floating balance if you add Polyester/Nylon, it might be compromizing on the weight of your rope but needs to be still floating well.
- Never buy coreless ropes!
- Buying an expensive rope containing Dyneema (Syntec, Spectra) expands the tensile strengh but not the abrasion resistance.