TIP load

Tom,

I'm glad you mentioned this, "....how can we tell what sort of [theoretical] safety factor we have at the TIP? "

I have wondered about that almost everytime I start to climb. My problem is I don't know what safety factor is considered acceptable for the TIP????

I hear about the 10:1 margin for rope, gear, etc. but I don't believe I've ever heard what margin to expect/test for on a TIP????
 
When I bounce test I'm generally trying to be sure my rope is where I think it is and there are no little twigs holding it off the crotch. After breaking one (during a bounce test) I'm pretty paranoid so I only go for fatty crotches from the ground and move onto the finer stuff once I'm up where I can have a look at'em. If that means going lower than I want, so be it... I like climbing on the tree anyway.
 
Having only been climbing for almost two years, I have come to except that any branch can give out for any reason that I may not be able to see from the groiund. I bounce test, but just last week I set up a single line in a big white pine while my boss was working in the bucket truck. I tested the line and it seemed safe to climb. I was about four feet off the ground when my boss stopped me. While my rope looked like it was over a 6 inch branch it really was over a 1 inch branch that held a bounce test. Since it was a white pine I reset my line. Sometime what you see is not really what you have set up. Thats tree work. Thats way what we do is dangerous.
 
Blinky, That is how I use the test too.
Tclimberr, Its good you have someone else to pay attention like that.
 
[ QUOTE ]
Tom,

I'm glad you mentioned this, "....how can we tell what sort of [theoretical] safety factor we have at the TIP? "

I have wondered about that almost everytime I start to climb. My problem is I don't know what safety factor is considered acceptable for the TIP????

I hear about the 10:1 margin for rope, gear, etc. but I don't believe I've ever heard what margin to expect/test for on a TIP????

[/ QUOTE ]

This is why knowledge of tree bio-mechanics and species characteristics are essential to safely climbing and working amongst them. Read claus Matthecks work to understand tree safety factors and the axiom of uniform stress.

On another note regarding bounce testing - this is essential in my book. I use two bug guys, with a foot in a handled ascender loop. This way they can stand and if something gives they land on their feet.

Second, always have the line rigged over several smaller limbs or one 'bomber' limb.

The danger comes from the first three meters - if the twig you didn't see snaps, there could be sufficient slack before catching the branch to land you on the deck on your butt (very bad). More slack than this and you'd certainly have noticed it visually via line angles (ie line over twig above branch) - I carry a small cheap pair of binos to check after the high viz access line is up. Proof loading with twice body weight and bounce will give the all clear for the initial two meter runway. After this a safely set up system will have sufficient energy absorption and ground clearance not to worry about it.

There are other options to reduce the risks of ground strike in the first couple of meters. Use your groundie to 'spot' you, breaking your backwards fall more upright. and you can even use a bouldering matt. Oh yeah, and i see guys using a chainsaw to weight the line - maybe not such a good idea in light of the above.

The hazards are the same with footlocking, only the risk of injury greater and controls limited.
 
"...While my rope looked like it was over a 6 inch branch it really was over a 1 inch branch that held a bounce test. Since it was a white pine I reset my line. Sometime what you see is not really what you have set up."

A similar thing happened to me in a pine. I had the limb I wanted and even looked at it through binos and everything looked great. When I got up there, the limb was much smaller than I thought it was. It wasn't too small, but it was eye-openning that I had misjudged it's size. I think part of that was because the limb I picked looked big compared to limbs around it.

Laz
I've been using 2x my weight to test limbs, except I don't have a second person, so I have to rig a simple 2:1 on the climbing line to multiply my weight. Is 2x enough or maybe a light bounce in addition?????
 
LOL! I hear ya on the buddy thing! Unfortunately tree climber buddies around here are as hard to find as hen's teeth.

Thanks for the advice, I will start doing a 2:1 with a light to moderate bounce.
 
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