just orderd the powder coated large porta wrap

Maui Palm & Tree Care

Maui Palm & Tree Care

Location
Pukalani, Hawaii
man am i ever excited! i just got a large portawrap along with 150 of 3/4 double easterlin. i used this porty on a job helping my friend this week lowering some moderate sized branches(4-5 feet x 10-16 inches diameter). it was smoother then the original chrome steel porty's i have used. whats your impressions on it?
 
Mine is the anodized unit, and it's fine.....

But I hope you're planning on using that 3/4 line on some heavier applications. 1/2 inch line or 9/16th at most, is plenty for loads that size you mentioned.
 
tons of shock loading. negative rigging is what you do when your blocking down a spar or leader trunk. rope goes from a porta wrap attached to the base of the tree where it then goes up through a block cow hitched to the tree. the rope then comes out of the block where it is half hitched to the piece and then the rope runs around the piece again then finally tied off with a running bowline or clove hitch. climber cuts the piece then pushes it down where the block catches the load and groundie lets out rope to lower the object. preferably letting out rope as the piece is falling so there is no sudden stop of the falling piece to minimize shock loading the ropes and slings. that to my knowledge negative rigging.
 
Even with blocking aka “negative rigging”, with the size pieces that you mentioned a 9/16” double braid should be fine.

As an example, let’s say that you have a 4’ piece of Red oak that is 12” in dia. This piece will weigh approx. 196 lbs. If you tie it off at its COG, that is roughly 2’ up from where you tie off your block and make your cut.

Using the following “shock load” formula: shock load = (weight of section x drop in feet)+weight of section. If you were to snub off the piece, you would be looking at roughly 980 lbs of force. This is not taking into account the friction at the block or the elongation in the rigging line, so obviously the force could be greater.

With the WLL on a 9/16” double braid being approx. 1,330 lbs. I would have no problem using it for rigging as you have described. In fact we use a 9/16” line for most of the rigging work that we do.
 
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...This is not taking into account the friction at the block or the elongation in the rigging line, so obviously the force could be greater...

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Elongation, friction, tree deflection, etc all decrease peak loading, fwiw.
 
Joshua,

You might try to estimate the weight, then measure the weight of your pieces. Are they dropping from directly overhead, so dropping roughly 180 degrees. What type of tree? What does the green log weight chart for that species tell you to expect? Using the formula for the volume of a cylinder, with an averaged diameter and specified length will tell you the weight per cubic foot. You can weigh some sample pieces at the job, then extrapolate to the larger pieces (if you don't have a green log chart for said species). This will help to put your concerns in the proper perspective.

Pretensioning the rope through the POW will allow you to gain control sooner, via the rope. (Sweating-in/ Sweating the rope, or MA, or just pull hard and advance slack through POW)

Leather gloves on the groundie and expressed instructions on what it should look like/ feel like will help. I had a rookie catch his first top the other day. Years of life experience, and expressing to him that he will have to be more concerned about locking up the rope, possibly snapping the rope,than dropping the piece made it smooth. Make sure that they let it run beyond your feet so that you don't get crushed. If they are directly under the tree, they will be more scared. If they are away from the rope, with the rope stacked well at their feet (bag or not), with all the rope in front of them and nothing behind, no wrapping around hands/ arms/ body!!!!, with a good angle of view to see the piece running, then they should be pretty well set.

If you are negative blocking from very low on the trunk, where you have very little rope in the system, you can redirect through a block at the base of the tree, to a POW at another remote tree, running the rope horizontally-ish, to add rope to the system for greater elongation. You will just have to be a bit more careful to stop it in time over your obstacles, but it should be no big deal.

Sounds like you are fine with the rope and weights you are handling, though, so even if they accidentally get snubbed, unless you have some wood that sinks in water over there.



You might benefit a bunch by Jerry Berenek's Working Climber DVD series, or you can rent Arbormaster DVD's through Bailey's (I think Bailey's).
 
Yeah, I know. I didn't want to list every variable, just wanted to point out that you can do a rough estimate while in the tree.

Being able to estimate pieces and build your rigging system based on that and other conditions, will help riggers decide which gear to purchase and when to use it.
 
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man am i ever excited! i just got a large portawrap along with 150 of 3/4 double easterlin. i used this porty on a job helping my friend this week lowering some moderate sized branches(4-5 feet x 10-16 inches diameter). it was smoother then the original chrome steel porty's i have used. whats your impressions on it?

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Congrats on your new investments.

The 'powder coated' porty is the way to fly. The nickel versions are too abrasive, IMO.
I have 2 porty 2's in nickel and only use them to "hold" the rigging, as I have experienced abrasion on my lowerng lines when using them to lower. If I have to lower, the powder coated porty 3's come to play.

Be careful in the size logs, or the weight of the pieces your riggin. You're doin just fine in using a 3/4" DB for what you're doin. It's much better to be 'safe', than be 'sorry'. A complete understanding of the dynamic forces involved with 'negative' rigging is essential. "Read to succeed".

What type of pulley or block are you usin (please be specific; i.e., CMI arborist block), with what type of connection (spliced eye sling or ??). Pics would be best.
 
i have 2 blocks right now. i have a newer ISC spring block blue and an older CMI block with a zinc coating. both are 3/4 capacity. again normal blocking and over head rigging is a no brainer to me and i have at least 2 full years of experience with it. speed lines are just soo complicated to me even though they seem like the would be easy. im smart though and dont wanna do anything dumb. thanks for all your input. i really appreciate it. i hope to be as good s you guys some day. :)
 
If you're looking for additional blocks, don't pass up on the Hobbs Block just because of the price. They are without doubt, the best Arborist rigging blocks in the world IMO.

The 5/8" Hobbs is my main workhorse for a block.
 
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you know i thought about getting a half inch or 9/16 double easterlin. i think i might get a half inch since it seems to handle more load then a normal 1/2.

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It depends on what type of rigging you're doing, but a polyester cover/nylon core DB should be considered (Yale's Polydyne). It will reduce shockloads, due to the nylon core fibers. Should be no difference in $.
 
it is very reare to need a 3/4 inch line. It will wear the hell out of you dragging that thing around the tree. 3/4 inch line is for the really really big stuff. you dont want to wear yourself out in the tree if you can help it. I have a velocity rigging line and a 1/2 double braid. those two lines get 90% of my jobs done. My
3/4 is almost 2 years old but looks brand new.
 
i have always been the "better to be safe then sorry" type but also like to keep things practical so i have been using a 7/16 double braid polyester in place of an old climbing line. and with 8,000lbs breaking strength im comfortable.
 
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it is very reare to need a 3/4 inch line. My
3/4 is almost 2 years old but looks brand new.

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This brings up a good question that I have about the "shelf life" for a rope, but I don't want to derail this thread, so I'll start a new post.
 
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