Rope on rope friction

[ClimberInAFlatLand]

Hello Riggers, I've started working for a large leisure company that run tree-top zippline courses.  Their safety procedures are generally pretty good, but one of their rescue systems routinely runs a hauling rope against a stationary line because of the way the ground anchor is set up.  I reckon this could damage the stationary line, which the rescuer is on, by burning it with friction, so the rope could fail and drop the rescuer. I'm struggling to make the people I work with understand it is a problem.

1.  Am I being a wuss about it

2.  Have you got any resources I can point to so I can say 'we need to change this'?

Cheers

Pete

[Steve Bullman]

1. absolutely not.  Rope on rope should be avoided at all costs.  Do you have an photo of the set up?  I'm sure there would be a quick and easy solution that wouldn't cost them much money.

 

What sort of rope are they using, poly or nylon?

 

2. Show them this

 

 

[ClimberInAFlatLand]

Hello Steve,

Not sure about the rope, I think its nylon: pretty standard looking 11.5 LSK

On the photo, the line running diagonally to the bottom right corner (black) is crossing the red line which goes straight down, you can just about see that it is wrapped around it and pulling the red line out of true.

You've hit the nail on the head: it is easily fixable by the belayer just walking around to the belay point in a certain way.

 

[Vespasian]

55 minutes ago, Steve Bullman said:

1. absolutely not.  Rope on rope should be avoided at all costs.  Do you have an photo of the set up?  I'm sure there would be a quick and easy solution that wouldn't cost them much money.

 

What sort of rope are they using, poly or nylon?

 

2. Show them this

 

 

everyone who works with ropes needs to watch that..  terrifying how fast that rope burned through..

[Steve Bullman]

38 minutes ago, ClimberInAFlatLand said:

Hello Steve,

Not sure about the rope, I think its nylon: pretty standard looking 11.5 LSK

On the photo, the line running diagonally to the bottom right corner (black) is crossing the red line which goes straight down, you can just about see that it is wrapped around it and pulling the red line out of true.

You've hit the nail on the head: it is easily fixable by the belayer just walking around to the belay point in a certain way.

 

Nylon has a much lower melting point than poly so should be doubly cautious

[Steve Bullman]

5 minutes ago, Vespasian said:

everyone who works with ropes needs to watch that..  terrifying how fast that rope burned through..

It was, surprised I haven't come across that little gem before

[ClimberInAFlatLand]

Thanks for the help. I brought it up with my supervisor: I had all my ducks in a row so we are changing the training for the rescue system.  He liked that vid and we're putting it into the staff training.  Job jobbed, everyone happy.  Thanks a ton, it makes a difference to have support from the community.  Pete

[Mesterh]

Sounds like that worked out well then.

 

Good on you for not only spotting a danger but for doing something about it.

[Stubby]

Just as an aside . Anyone melted a  prussic ? 

[westphalian]

I have but my fault. I just used some cordage I had not knowing it’s friction qualities . Won’t happen again plus I no longer use prussik /Blake’s for descending