Half Hitch

[TheTreeSpyder]

Half Hitch Force Reduction to Knot

I've heard it said that the Bowline is the 'King of All Knots', the Clove, the mother(?); i think the half hitch then the GrandMother.

But any way, if you have a bowline and precede it with a half hitch, how much force does the half hitch dissipate/ not pass to the bowline? i think this is a strong strategy, as it gives 2 chokes on load, and takes the main shock off the joint/knot. If a killick pulls straighter on ground than related timber hitch; i theorize some kind of straighter pull through half hitch than any eye.

For years i have been using 1 or 2 half hitches preceding a bowline with a karab in it. i have never had a problem with this. MM came out strong when i started edging this way before, when talking about side loading karabs, and i let his words ring out about safety (with no preceding half hitches we were taalking at the time, just 'running karab' loop). But, now that placed, still wonder about how much weaker the pull is on karab in such a position, how buffered it is from the shock/ pressure of loading with a leading half hitch wrapped around moderate spar. Or, how much force a preceding half hitch takes off any latter hitch, whether it be a clove, bowline etc.

i go for low shock methods, and scrupiosly tighten from 'running karab' and all half hitches, by placing them too far to the side slightly, and using the pull line to tighten/ pull hitch into proper place. Having the line bent back sharply to itself when doing that, can give up to 2x your pull, the less tight 'V' you pull at the lower the mechanical advantage/leverage. Impacting into that 2/1 with body drop or rocking back and forth is about as much as i can feed into that 2/1 i figure. Then we tighten the rest of the rig after that. i think any slip in the lacing to the load, gives impact/ increase of force on hitches as they have play in them. i think you can think in foot pounds of increased force, kilonewtons; but also 'PSI' (no not the psi factor), per square inch, not let an inch of play in anywhere you can help.

When calculating where the hitch is in ratio to the C.o.B. we look at the first hitch that grabs spar, and beleive the C.o.B. should be outside all hitches, to effect pulling them all positively closed in the same direction.

An ol'mentor of mine has said for years, that the tightened line between the half hitch and running bowline adds something, a bracing/ stabilizing something, do to this tight line pressed to it, as the line traces from the half hitch to the bowline. He has had me believing him too. But to place the lead hitch near the C.o.B., and have the running bowline on the same side of C.o.B. as half hitch i use a shorter run of line between the 2 chokes on the spar. But i think he has something there, he leaves that leg long, and it seems that the length gives him control.

 

[Tom Dunlap]

Without access to a rope breaking dyno it is too hard to know about strength or effeciency issues. Adding a half hitch does keep the rope fair to the input angle of the running bowline. This can add a level of security. This practice also will tend to keep the choked position and not allow the bight to open up. Think of the disaster from having the bight open up in mid air. Bombs away!

Tom

 

[John Paul Sanborn]

Some say a half-hitch is as good as a marl in this application. I don't agree though.

Anyone have a reason for prefering the HH?

 

[Tim Gardner]

By marl do you mean the one that holds the rope in place while you tie the running bowline on the spar when roping wood down?

 

[Tom Dunlap]

Go back into the deep, dark, ancient archives of the ISA site in 1999 to see what I figured out:

http://www.isa-arbor.com/archives/isa/treeclimbers/1998/2458.html

Tom

 

[TheTreeSpyder]

Wow, Thanks Tom!

i use to prefer what i thought was half hitches more definitive choke, easier adjustment and release, will have to play with this angle.......

Sounds like on pieces that were wider than long, where it is hard to get C.o.B. outside both leading hitch and bowline, that the marl would REALLY shine.

And what of being 'lazy' and finishing with 'running'/reusable karab rather than running bowline, after initial hitch(es) take most of the shock? i have the same karabs for years, only remeber 3 or so getting 'sprung'/ bent open; all in utility positions of dragging with truck and getting hung up etc. Been pretty lucky to ben buying steel 5k screwlocks 10/$50 for years (maybe not anymore !), so replaced older karabs every once in a while. Been using half hitch running karab for years in all but largest rigs, is that pushing 'it'?

 

[Tim Gardner]

That is the one I was talking about Tom, thanks.

 

[FBerkel]

Spider,

I guess it comes down to not knowing when that karab will fail; maybe the extra 5 seconds to tie the RB is worth it for the peace of mind, not to mention what damage might occur when it does fail. But you're right about the hh or marl, either one, greatly reducing the load on the running bowline or karab.

A related topic: how to rig a very short piece without either losing the marl off the end (with the knotch being wide, because you don't want the piece to jump, it ends up taking alot of the available rigging length away from the underside of the piece), or tying too close to the center of balance to where you risk having the piece flip over.

Two years ago I had to remove a tree with a leader that ran very close over the eaves of a house. The stem was a little too big to toss pieces, unless they were pizza slices, and too many of these to consider doing it that way; no other leaders anywhere near enough to rig off. So I wanted to butt hitch 2 foot long chunks (2 and a 1/2 foot diameter). I cut wide knotches, and put in a 1/2" j-lag right above them, threaded the line through the j, so the marl couldn't possible slide off the bottom of the pieces. (pretensioned with a GRCS). It worked like a charm, though tt was a lot of extra effort to hang out under the leader and drill.

Any other solutions to this problem?

 

[Stumper]

Other possibilities would include cutting a small notch or double wide saw kerf for the rope to wrap in......or.... Screw in tree steps don't require a seperate drilling operation.

 

[Tim Gardner]

Stumper, I remember being a groundie watching climbers using a knotch cut into the spar to rope blocks of wood from. I think Oxman posted some pictures of himself using this method here on AS.

 

[TheTreeSpyder]

i cut a dbl. wide kerf down like ears into piece to be lowered just over slant of face cut if there are no imperfections to naturally dawg the rope into for a positive lock, then pro-ceed to next choking hitch/marl / RunningBowline, dogging each ring into natural ledges, crotches. You can cut a conventional knotch on blocking out on same spar(rigging under), that would invert to humboldt type and hold agianst upward pull from line.

i was kinda thinkin' Stumper meant the same thing. That rope rubbing on itself i think is unnecesary, seen guys around do it, though not test the theory like OxMan!

i think anytime that the choking rings are not pulled positively closed by the C.o.B. (like when C.o.B. is between the choking rings), you will have a problem brewwing. i'm hoping that Tom's Marl solution will help on that.

i keep a double bowline with tie off and screw lock karab in that temporary eye all day. i hang it on my belt with karab, use steel karab as throw weight, rig most things to eye with sling, slings come back up; that karaab is always free to hang on my belt. For bigger stuff, i lace half hitch(es) down to RunningKarab setup. So it is multi functional for me. When the loads get heavier, i do recede to the safety of the RunningBowline.

 

[Stumper]

Tim, Yeah, I remember Oxman's post-but I was talking about what Spydy was thinking. A notch in the piece being roped with the rope choked into it isn't likely to let the rope slip out/off. I can't say that I 've never RUN a rope in a notch in lieu of a natural crotch but I haven't done it much and not at all for ages-It is too easy to sling a block or a figure eight.
Actually, in lowering heavy, short chunks I've done a lot of stuff that wasn't hyper-critical by tying a clove with the legs spread, choked tight and backed up with 2 half hitches.

 

[John Paul Sanborn]

How about this Fred.

Bo'lin on the front of the wood
stilson an eye sling on the back end
connect eye to rigging line with butterfly if there would be too much slack to let it run

I've twice done this setting the slings out like eyes on a fishing rod.

moving down the branch, I'll make a cut behind the last sling, put a pully right behind that and do a snap cut as the groundies take up tension.

 

[Tim Gardner]

I misunderstood Stumper’s post. Thanks for the heads up Ken and Stumper.

Ken, about the rope rubbing, how would wrapping the rope around a spar and crossing through a notch cause more rope rubbing than if you took a wrap around a crotch in the top? If you rig the line properly, the standing end lies on top of the working end. This is so it does not lock off while under load. The wrap takes most of the load so the standing part applies little pressure on the working end. I can see this rope on rope friction if a line was run through a loop as a crotch. My father’s company was started over 34 years ago so I was able to witness a lot of “old school” techniques over the summers and then full time after finishing high school. We used this notch method to lower blocks on many occasions and I can not remember damaging a rope to the point of retirement as a result. I am not implying that this method is acceptable practice anymore but not as bad on ropes as one might think. A pulley and sling is much friendlier to a line. Maybe not as fast as the notch method but easier on the line. I would be willing to bet there is more rope on rope friction with a climbing hitch or a munter hitch.

 

[John Paul Sanborn]

The double wrap is now call a "High Strength Tie-off"

lowering off a halfhitch in a false crotch notch (what i first learned of as a FC way before I's heard anything about 2 rings in a sling) is probably no worse then a munter or figure 8 as a lowering device as to rope wear. Just not as easyily controled.

 

[TheTreeSpyder]

TimG. At the low end of weight i guess there is enough forgiveness, but as weight/force increases beyond friction on branch (impact, instead of hinging) i have seen guys bite the control line leg/standing end into the load line leg / working end while lowering, stopping from swinging while lowering. So i guess i associated both practices, and shoulda known better! And i have seen it where the control leg is under the load leg, loaded where it doesn't pinch itself off, just grinds as it moves! i guess most of what i have seen of it, was the least polished by the most questionable.

i beleive in slow, overhead friction, pretightened, then self tightened before hinge seperates; look at line as a wearbale resource, with a downgrade path. So am no friction purist, but beleive rigging under something is one of the more severe impacting force situations, perhaps could be given the pretightening, less friction, availaable to control run that a pulley offers at un moderate levels.

Hard to argue with continous success though!


don't like muenter except for adjustable light utility tie off, it and fig. 8 too much spiraling, especially on long or stiff lines. Don't like the grinding of muenter even with fly-body-weight on it.

JP; i guess i like the way ya think, even for a big guy (generally figure the air up thar must be pretty thin or something); i have done and admire working down the limb reusing ling connects, thinking ahead several moves; like a chess game, seeking multiuse strategies, and powerfull transitions. Especially if ya can shift from bulking out to manicuring to the beat of the ground crew clearing the bulk cuts smoothly....... But, don't think i'm going soft on ya!


:alien:

 

[Tim Gardner]

I guess if you do not know what you are doing you would screw up something as simple as taking a wrap up top. I guess you should have known better before ascending. The only time a wrap should be taken up top is when there is a chance a rope will jump out of the crotch. If using a notch and crotches for lowering gets a job done faster than fooling with slings and pulleys then I will not ask for one to be sent up.

Ropes are a lot cheaper than payroll. If you have a crew standing around waiting for a climber to install a pulley when a notch or crotch would do then you are using very expensive ropes. If someone can't afford to be rough on a lowering line then success has not been achieved.

 

[Kneejerk Bombas]

Tim, I respectfully disagree with your last post.
The time difference to hang a pulley is a matter of seconds, and possibly faster. Also consider the possibility the limb being lowered hangs up, without a pulley raising it is sometimes impossible, now who's wasting time? What if some pretentioning is required?
Once you abuse a rope, even once, how can you trust it? Are you suggesting a new rope for each limb, or tree, or job, or what?
If you are working on a saw and you need a certain wrench, do you just use the hammer because it's handy and you can't justify the time it takes to walk over to the toolbox and get the correct tool? Heck, you can get that part off the saw with the hammer, if you can't afford to just replace the part, you must be a lousy mechanic.

 

[Tim Gardner]

Dang Mike. Your post is way too funny. How often do you hang limbs up? I know you are just kidding around and you are not stupid enough to think someone would use a different rope for every limb or use a hammer in place of a wrench. And how weak are your arms if you can not pull a 1/2 line over a tree crotch or lift while a groundie pulls?

Just because a rope gets dirty looking and a little fuzzy Mike you should not throw it away. If a rope gets nicked, cut, overloaded, etc I will use it for non rigging applications. I have a hard time believing you think a rope is so fragile. It was not uncommon for us to use a lowering line for a year running it through natural crotches without them failing. But we were not so lazy that we had to dump a whole top or large leads on the groundies to deal with. I never said I used the notch method of roping wood blocks down. I witnessed this being done.

Time to throw that wal-mart rope away Mike and get some real lines that stand up to a little more punishment.

 

[Kneejerk Bombas]

Having done it both ways, first without blocks for years, then with them for years, I can tell you that that almost without exception I hang a block or set up a retrievable false crotch. My groundmen appreciate the few seconds it takes to hang, and I appreciate the few seconds it takes for them to tug the line once it's disconected, to get it back to me. The other advantages are to numerous to list, but if i were to list them, keeping ropes safe and in like new condition would be near the top. If you give pulley rigging a shot, I think you might find it has enough benifits for you to start do it that way all the time. You will also find the time it takes to set up is only seconds.
When I decide how big a piece to dump on my ground crew, I use other criteria than how bad I'll burn my rope, or tear the cambium should the TIP be in a preserved tree.
Having a rescue block, carabiner, and speedline strap, on my belt for this porpose is virtually unnoticable to me, so I carry one set, and two often two for removals.
If old school works for you, then great. Tom Dunlop has made the point before quite well that knowing old school is important, although I think that companies that have and use modern rigging techniques, including proper sized blocks, ropes, and friction devices like the GRCS, are the ones who have achieved success.