Another thinker

This is a white oak we did last week. We had a strong wind that broke half of the tree out and landed on the clients home. She was in the room where the limb went thru the window.
About half way up you can see where the spar gets smaller.
 

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In this pic you can see the section laying on the house. The split was about 11 feet long. The window in the upper right is where the client was when the limb broke off. There was alot of shingle and gutter damage, but only 1 broken window.
 

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This what we had done by noon. We topped the standing portion 1st to reduce the weight in the crown. We then started removing wood from the broken section using the GRCS and a 1/2" DB. We installed a side swing control line anchored to an adjacent tree (it's the white line going to the left).
 

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When we reduced enough weight to hoist it off the roof with GRCS, we set up a DWT using a 9/16's poly/dyneema DB. The GRCS was at it's limit. The winch would turn, but the rope would not. We were able lower it back on the roof and get 1 more turn of rope on the winch, which hoisted it clear of the roof. Before we started hoisting, we installed a side swing control line going in the other direction and anchored to an adjacent tree.
 

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This pic shows the CMI block for the DWT, and the red object(upper left)anchored to the pine is an ISC block we used for the brush of the standing spar. We used this to increase the rope angle on the white oak to help reduce the loads.
 

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It looked like there were a lot of power lines nearby, was there no crane access? Or were the power lines prohibiting use of a crane?



That old oak looked like it might have split a long time ago, judging by the woundwood near the top of where it split from.


Good job with the rigging, though, the GRCS is one nice tool!

SZ
 
This pic is a close up of how the DWT is rigged just above the break. I chose to use a double clove for the tie off because of the loads applied and it is very easy to untie after heavy loads. The block is anchored with a cow hitch using a 3/4" BD.
 

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This pic shows the section laying on the ground. You can see we also used a butt line to prevent the butt from moving, a re-direct for the GRCS line, the crew is removing the side swing control line on the right and we plywooded the sun room to protect from windows breaking.
 

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Stephan, there were pole to pole lines on the back side of the tree approx. 20' away. There was no room for a crane to swing a boom. We barely had enough room to get a bucket back there. There was not even enough room to haul brush and logs out with the bucket truck set up. All the brush was stacked on the back lawn and chipped after the bucket was pulled out.
 
Great job, thanks for sharing. Looks like a riggers dream (or nightmare depending on what moment you catch them at
grin.gif
)

On the pic of the stem being felled it appears that he is boring out the centre of the hinge AFTER the back cut? I'm surely wrong and it's just a marker cut or a bore cut?
 
Could you set up a "double" DWT connected to the GRCS to increase the MA? If you don't understand what I mean I can try and explain it further.

Good Job


WP
 
I had to plow out the center of the notch because I didnt want to "trim" any more of the hinge. The stern had about a 10 degree lean towards the house and a 5 degree back lean. Two forces that I had to control with prescision. Even with a 5:1 with two guys on the MA she would'nt come over center. Thats when I made the calculated risk to bore the apex, even though the back cut was made.
 

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