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Rope binding on Hobbs device

Discussion in 'Commercial Tree Care and Climbing' started by MattBanchero, Aug 11, 2019.

  1. MattBanchero

    MattBanchero ArboristSite Lurker

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    So I pulled a first generation Hobbs out of my shed for a project last week. I picked it up for $500 from a buddy a few years back but I haven’t used it for much. We do lots of big tree removals but I can usually get away with just a portawrap or free felling logs. This job the fir tree is between two houses so I wanted to pretension the line.

    When we took some pretty big tops and the first chunk of wood the rope kept skipping and flipping over itself on the cap stand. The last piece locked itself off and sent me for a pretty good ride when it came to a sudden stop 10’ below me.

    I’m not sure what we’re doing wrong here, but that thing isn’t working right at all. Running 3/4” stable braid. The Hobbs is tight and level on the tree.

    Any advice?

    I’ve seen videos of the H-2 Hobbs and it looks nice. There is a second fairlead on the underside on the cap stand to control the tail. This unit doesn’t have that.
     
  2. Del_

    Del_ Get outside.

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    It might be that slack develops in the system as it goes to a very short term 'no load' situation. Then when the rope pulls tight under load the wrap closest to the Hobbs crosses other wraps. I've had it happen.

    To prevent this the Hobbs operator has to keep a steady pull on the rope and take up this slack. It may mean a foot or two of rapid pulling just as the piece comes off the tree.

    The trick for the Hobbs operator is to take out this slack rapidly and then switching instantly to allowing the rope to run through their hands to lessen the shock load in the rigging system.

    A casual observer may not notice that a skilled operator is doing this on almost every piece lowered.

    If one listens closely though one can hear the ratchet sounding off as the load goes from free fall to being a load on the rigging.

    Hobbs slack.png
     
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  3. MattBanchero

    MattBanchero ArboristSite Lurker

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    Shnaszzy picture. Thanks.

    I gotta hand it to my Groundman. He’s been with me for 10 years, we’ve rigged some huge stuff together generally using a portawrap and I rarely feel anything. Not his fault at all, I wasn’t coaching him to suck in slack. We don’t put much time in with that Hobbs.

    Looking at the modifications done for the H-2 I think I’m going to weld on it a bit too.

    Matt
     
  4. Del_

    Del_ Get outside.

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    Another way the Hobbs can become fouled is when lowering a piece is letting the tail of the rope overlap other wraps. Avoided by holding the rope so it enters the bollard when it belongs.

    I got my first Hobbs in 1989. I saw it at a demo and just had to have it.
     
  5. DSW

    DSW ArboristSite Guru

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    I have no experience with the Hobbs and I've heard nothing but good things.

    That being said, I'd sideline anything that sends me for a ride, I'm not trying to recreate that Six Flags experience up on a tall stem.
     
  6. MattBanchero

    MattBanchero ArboristSite Lurker

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    Del_, we had the tail going over the top of the spool, running off to the right on the device.

    Looks like it should have been running out the bottom off to the left. That’s not what was easy and obvious on that job site but hopefully we figured out how to fix it.
     
  7. Del_

    Del_ Get outside.

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    The line needs to be fed to the bollard exactly so there is no overlapping of wraps. This means standing pretty close to the Hobbs.

    I've had wraps overlap and bring a lowering to an abrupt halt. It sucks getting it unfouled.
     
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  8. tree MDS

    tree MDS Daddy

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    Grcs seems to have the same issues.

    Great posts, Delco!
     
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