Cobra Bracing Tips??

Bermy

Acolyte of the short bar
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I'm about to install my first Cobra bracing in a massive English oak...any tips, tricks, things to be on the lookout for?

Installation seems pretty straightforward from reading and watching the videos, but got to do it for real now.

4t system, will put two on a big branch that has a split in it, for support as the branch union is a good angle, but the weight has just overwhelmed it and split it longitudinally. I have already reduced the endweight.
 

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Pretty straightforward, I think I learned to do it by watching videos. Only installed a few however so no expert by any means.

That is a huge English oak. The ones around here, at least what we call English oaks, are just little columnar things.
 
Install the awkward side first, put the ding dong in and then transfer to the side wit the best tie in. I like to take a loopie up with me to support the weight of all the dangling cable, I never pre cut it. When making your splice, be generous with the cable, it is better to cut off a foot after the splice is done than to need an extra few inches and start over. Also, make the splice and growth loop but if it is a long span, use up the growth loop before making the second splice, it will make the second splice easier, then when both splices are in place, go back to the hard side, tighten things up a bit by pulling the growth loop back in place, transfer to the easy side and set your final tension with that loop.
 
I've never done a Cobra system, but I've installed many a cable in my time, 25 years ago.

Interesting.
 
I'm almost positive that cobra is not recommended for a limb with a cracked or co dominant stem. I would use steel in that situation and bolt crack as well
 
I seriously doubt you'd be doing the tree, client or yourself any favors by using a Cobra system in that tree Bermy.

IMO that crack should be rodded, and a static steel cable with throughbolt anchors used to keep that tree together.

Much like I did with this highly valued old Torrey pine next to the boardwalk on Mission Bay in San Diego.

http://youtu.be/xa1ucSTo04k

That's a nasty lookin crack that should be taken seriously IME.

Jomo
 
We do a fair bit of it when I am working in Norway. I tend to go by the way I was shown. Install brace approx 2/3rds of the way up from defect. Measure the collar and cuffs up and install the difficult side first. Then slacken it off.

It helps to have a spare crab on you saddle to hang a bag or something else on with all the kit. We use a couple of stiff bucket type rope bags. Have a sharp knife, blow torch, collars, cuffs, dildos and lube, shrink wraps etc.

When you go to the other side measure the brace etc taking into account the slack you created. When you measure I tend not to cut until the collar is inserted. Always insert towards the spool end or open end of the line. As the collar goes in it expands the braid. Therefore if you insert in the direction towards the other brace you will find it is shorter than you measured.

Once it is all in place with the collard inserted you can estimate the bury and expansion loop and then cut the line. Shrink wrap and then do the burry and finish that side. Go back over to the other side and retension the system.

We don't tend to insert the dildo on spans over 4m.

Hope this helps.
 
How much endweight came off? can not see in pic.

Totally agree that stabilisation has to be the goal, and polypropylene ain't the way. EHS steel cable with wedgegrips!

Cobra can be great, when movement is a benefit. Not so there, as viewed from here!
 
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Interesting, I was thinking about putting some bolts through the crack.
I wasn't going to put the shock absorber in as it is a stabilising situation, Cobra shows installing the line in a more vertical situation When a more static situation is required.
Something's got to be better than nothing...
Keep the info coming!
 
I've read up on my Branch Saver literature, which is similar to Cobra, and they also say Dynamic is basically for storm-proofing, and will allow response growth to continue. Even they recommend wire cable where stabilization is the goal or where a failure has already begun. What do you think? Will that oak be able to seal up that split? Stranger things have happened. . .

Being all that as it may, I really enjoy putting the stuff up. Only done it a handful of times, but it's actually pretty fun. 8)
 
"I've read up on my Branch Saver literature, which is similar to Cobra, and they also say Dynamic is basically for storm-proofing, and will allow response growth to continue."
The theory that static cable does not allow response growth to continue is just theory, with no data or experience to support it.

"Even they recommend wire cable where stabilization is the goal or where a failure has already begun."

Good on them for being up front about that!
 
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Thanks Guy and everyone...points to ponder
Might have to sub this job out...I'm not set up to do static cabling...don't think I'd have the strength either!
 
Working the hand winch (come-along) is probly the hardest part. not that hard! but job would go better with 2 climbers.
 
Thanks Guy and everyone...points to ponder
Might have to sub this job out...I'm not set up to do static cabling...don't think I'd have the strength either!


No strength required, compared to climbing trees.

Rig-guys are soooo easy. I was resistant to static cabling, until Rigguy. I knew that there was a reason, just not that I wanted to put them in. Easier than Cobra.
 
Working the hand winch (come-along) is probly the hardest part. not that hard! but job would go better with 2 climbers.

Your reply's a fine example of expediency in place of quality cabling Guy, and I'm calling you on it.

How the ef's a beginner going to be able to tension a cable properly following your advice mate?

You're old enough to know better?

Come along smumalong you BCMA shyster!

I can adjust my cables to the nth degree using old school through bolts, whereas what you're suggesting is as haphazard as aligning cables by eye.

Go brown nose Peter some more so you can get your crap published you snake oil salesman!

Jomo
 
If you'd been tasked with redoing as many shoddy cables in trees as I have?

You'd appreciate good quality cabling as much as I do.

Some old school traditions are worth preserving n promoting IMO.

Jomo
 
I'm sure you've cabled more trees than I've seen but Guy is one of the most polite people on this site. If nothing else, that should earn him some politeness in return
 
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