Rigging Study
- Thread starter treelooker
- Start date
- Replies 29
- Views 6K
M
Mr. Sir
Guest
Is there an abridged version? 
MasterBlaster
Administrator Emeritus
That's a lotta wurdz for "Rope it out!"
W
Wagnaw
Guest
I really appreciate how on the ball the Euros seem to be when it comes to safety, and it was really cool to get to talk to some of them about the study they're doing on tie-in point strength, bending, etc... I remember using a lot of the tools they use, but it all gets way more interesting when it actually pertains to what I'm doing. 
I wish the U.S. would sponsor that much research to keep workers safe. ...granted they may also start trying harder to make people wear chaps if they do.
I wish the U.S. would sponsor that much research to keep workers safe. ...granted they may also start trying harder to make people wear chaps if they do.
W
Wagnaw
Guest
My bad for double posting... but an interesting thing that the Treemagineers guys found with the "Worst Case Senario" rigging study was that putting a half hitch below your running bowline when rigging from above ends up putting way more stress on the tree than just a running bowline. It was all in that the slack in the half hitch added so much rope that the increase in the distance of fall greatly increase the shock load at the rigging point.
PCTREE
Treehouser
the US has no reason to do these studies to keep workers safe. We dont have socialized health care. Plain and simple thats why our safety regs arent as strict, dont wear chaps, cut yourself, then go pay for it.:roll:
PCTREE
Treehouser
You were typing as I was you sneek. Now that is interesting, if I used a half hitch I would have to think about changing......
CurSedVoyce
California Hillbilly
I down loaded it and I am definitely reading it over this winter... Should be some cold snowy days I will have nuttin else better to do. 
Thanks for the post treelooker. Now I need some more toner and a ream of paper to make another book for the library
Thanks for the post treelooker. Now I need some more toner and a ream of paper to make another book for the library 
When helmet and seatbelt laws were implemented here, the reasoning was that when stupid people get hurt, it costs society too much via socialised medicine to heal them again.
Well, it wasn't put quite like that, but the meaning was the same
MasterBlaster
Administrator Emeritus
Old Monkey
Treehouser
- Joined
- Mar 9, 2005
- Messages
- 8,767
When people get hurt without insurance all our medical costs go up.
T
top hopper
Guest
Really depends where the bowline and half hitch are placed doesnt it? If the half hitch adds say an additional foot of rope and fall, couldnt the bowline / half hitch combo simpy be moved up to compensate? Anytime you increase the distance of fall loads will be greater, but to say its because of the half hitch would be false in my opinion. A more accurate statement would be -that adding a half hitch and placing it so the increase in fall is greater would put more stress / greater loads into the tree and / or rigging system. Simple physics really.
T
top hopper
Guest
But arent all of our medical insurance costs going to go down now with our new president? :roll:
rbtree
Climbing Up
- Joined
- Jun 22, 2005
- Messages
- 1,924
Did you read the study? I read that part, briefly. I think your supposition is not what they found. I think the reason the line failed at the half hitch was due to friction from rope stretch and slippage.
Also, as far as butt hitch rigging is concerned, one should always place the lowering block as close to the top as possible. But, if the load is tied down a ways, all that means is more rope is out. The center of mass of the load still falls the same distance, assuming the load is snubbed off.
Main reason i see for a half hitch/marl before the bowline is to spread out the tie point to make it more secure, and lessen the chance of the rope coming off.
N
Nails
Guest
Putting the half hitch on also decreases the preasure on the final bowline knot.
,....but a half hitch is a much weaker connection so that reason becomes somewhat apparently foolish.
MasterBlaster
Administrator Emeritus
HuH? 
Half hitching in addition to choking a piece with a running bowline may serve a function in stabilizing the way a piece will hang but a half hitch is more prone to the liine damaging/cutting itself when shock loaded than is a running Bowline. Thus "taking part of the load off the running bowline" is a stupid reason to go to the trouble of working a wrap with half hitch into the rig. Mear as clud?
MasterBlaster
Administrator Emeritus
But doing that on a heavy load allows easier untieing, eh? It does for me.
MasterBlaster
Administrator Emeritus
Me either! 
Know what I mean?
Know what I mean?
gf beranek
Old Schooler
I've never been a fan of drop loading standing vertical work, because I have seldom work with a ground person that could fully understand the intricacies of letting the work run. Which invariably resulted in me getting a fantastic ride or getting hit by the work when it's caught and spins around.
During the drop load tests we did it was assumed that the failure point in the line would be at the marl/half hitch. And in one drop it was. Other line failures occurred at the capstan and in the line other than a knot. The line used in the test was well used and so any conclusions couldn't really be based on one specific cause of failure.
During the drop load tests we did it was assumed that the failure point in the line would be at the marl/half hitch. And in one drop it was. Other line failures occurred at the capstan and in the line other than a knot. The line used in the test was well used and so any conclusions couldn't really be based on one specific cause of failure.
M
Mr. Sir
Guest
Point taken Butch. However, I'm the weird exception one man show so I wind up untying most of my own knots. I also have a lot of experience working the ground-for my dad and for my own subs. In some lines a bowline can get sucked down to where it is moderately difficult to untie. mostly if the loads are not excessive for the rope the bowline unties readily. Of course you are also aware of my longstanding advocacy of taking smaller pieces compared to many aerial loggers.
Old Monkey
Treehouser
- Joined
- Mar 9, 2005
- Messages
- 8,767
The last climbing class I attended they recommended tying what I think is a marl but I am not certain instead of a half hitch. It looks like the first part of a simple square knot or the first wrap of your shoe laces before you ad the bow. The reasoning the teacher used was to not put a hard bend in the line. I have to say that I haven't really tried it yet and keep tying half hitches above my running bowline.
