Rap on Dynamic and Static

[Buckaroo]

Looking at a rap system like Colin suggests. Using a 50M dynamic twin and a 5mm x 50M Maxim Tech Cord for a double rope rap. Was wondering if the stretch of the dynamic rope is going to mean the static tech cord needs to be longer than 50M?

[genepires]

how much would 50m of tech cord cost? isn't it around $1.25/ft? Over $200?

 

I would figure you would need enough extra to cover 3% stretch. so an extra 5 feet sounds good. Maybe the mountain gods will release colin long enough to answer the question personally.

 

 

[crackers]

Yes, it needs to be longer than your rope.

 

Most climbing ropes have much more than 3% stretch too, like my new sterling 9.2 that has a 13% static elongation and a 32%ish dynamic elongation. Figure out how much your rope stretches, and then add that much extra plus three feet for knots onto the length.

 

And yeah, get Maxim tech cord or another KEVLAR product, not a spectra line. The spectra will get damaged if you put it through a belay device.

[Buckaroo]

I'm thinking if you're rapping on both lines the static line is going to hold some of your weight and keep the dynamic line from stretching so much. Think I'm going to test rap off of both and see where they end up and just cut the static there. It comes in a 60M length.

 

Maxim tech cord is not Kevlar, it's called Technora, 50% stronger than spectra.