Why no prusik?

[stephen0351]

Im new to caving. I haven’t been on a vertical trip yet, only to vertical practice. All the videos I’ve seen and the people at practice using racks or Simples nobody uses a backup device like a prusik, why is that? If you lose control of the rope on a descend for whatever reason you are going down fast. Is there something that prevents the use of a backup? Sorry if I should know this, I will now, thanks

[knudeNoggin]

Wow, oct'23 & soooo much silence.

Use of a gripping hitch for arresting out-of-control abseils has been deemed dubiuos/dangerous, given the tendancy to grap the knot, which will see it sliiiiiiddde & melt.
*kN*

[tempest766]

I'm old school so I've messed with everything from heiblers and beener brake bars to 90s tech when vendors such as pretzyl started futzing with lowering manufacturing cost of gear. The knot safety is a less desirable idea for several reasons, but the one the comes to mind to me is that in a decent the rope on rope friction could build up heat and cause wear fairly quickly on the prusik sling component. One place the knot safety shines is on haul sustems that may become shock loaded. since the movement is in small discrete increments there isn't the wear/friction problem. Also rope loading against rope is less damaging than a jumar/gibbs crushing the rope core if shock loaded.