Carburetorless
ArboristSite Guru
Carby,
I think you are way too concerned about rope strength.
Yeah, I'm a strong believer in extra safety.
While the human body can, if properly supported, survive a 40G impact, a climber won't come close to surviving more than 4 or 5 G's under the best of conditions, if the rope is what catches you. The problem is the way the rope is attached to your body. The focus point of load is basicly in front of your belt buckle, and will tend to fold your body backwards during the shockload. If you have both hands up on the rope to keep your upper body from flopping back, you might be able to hang on at 4 G's and prevent a broken back. Probably not at 5 G's. If you don't have any hold on the rope, you could get a broken back pretty easy at 2 G's. A 200 lb climber at 2G's is only applying a 400 lb load to the rope. When wearing a typical climbing saddle, your body is the real weak link in the event of a fall, not the rope.
A buddy of mine dropped about 4 feet when his friction hitch slipped then reset, he ended up with a herniated disc that eventually had to be removed. He was only about 8 feet off the ground when it happened.
Move the anchor point up high on your back, and things change greatly in the body's favor. That is why FALL ARREST harnesses anchor there, or high on/over the front of the shoulders.
Yep. My harness has rings on the shoulders that are for confined space access, there's a special lifting bar that attaches to them, but I don't know if it would work well in a tree, unless I had a groundie belaying me.
I also have fall arrest on the chest and back, but I don't plan on leaving any slack in my line.
A rope with a little more stretch would help if the hitch slipped, or even a self tending rope grab, the gri gri seems to work a bit like that, but I've never tested it out.
Even a parachute that was anchored near your belt buckle would probably break your back when it opened.
A reserve sort of does that, but if it's a combat jump you don't have the time or the altitude to worry about it.
I also use and like the PI from Sherrill Tree. I use an ICE eye2eye with a Distel hitch and a micro pulley.
Long decents on figure 8, and throw a quick wrap around my leg if dropping on the hitch for more than a few feet. It keeps the knot cooler.
Rick
Does that 8 twist your rope up?