rip cuts to reduce rigging forces

[Jehinten]

If I didn't have a mini, I would use it semi-regularly.

Probably the same here. I've wanted a grcs in the past, but it so easy to do everything that it does on the mini skid bollard. Maybe the grcs could lift more than I'd want to put on my branch manager grapple, but around here there often isn't enough room to lay something of that size down.


I'm certain it's a great tool, but it's one that I haven't drooled over in years.

 

[flushcut]

One thing with the GRCS is that you don’t need as much ground to lift something as with a mini.

 

[Jehinten]

One thing with the GRCS is that you don’t need as much ground to lift something as with a mini.

I also have a hydro winch for the mini, but I definitely get what your saying. Typically the winch is used for pulling and not lifting.

 

[96coal449]

Simpson Winch

Guess I could have just searched it LOL.
But thanks for the link. I was envisioning something quite different. Like a scaled down GRCS.

As is, I am intrigued to buy one. I see multiple uses and have the perfect rope for it. Bought 300' of 3-strand, at a used tool pawn shop, for $50 years back. Hell, I'd buy and bag 500' of 1/2'' stable braid or a Kernmantle if I had to.

 

[96coal449]

I also have a hydro winch for the mini, but I definitely get what your saying. Typically the winch is used for pulling and not lifting.

Couple years ago I used my GRCS to pull over a black locust that had multiple targets below. Had plenty of room on the HO's property to do so but needed to use a neighbor's field for the pull. Didn't want to drive on the field. Just carried the GRCS and mounted to a nice anchor tree.

 

[flushcut]

I also have a hydro winch for the mini, but I definitely get what your saying. Typically the winch is used for pulling and not lifting.

One of the OG capstan winches for the BMG?

 

[Jehinten]

One of the OG capstan winches for the BMG?

No. I bought this one off of fb market place. Welded a mini skid plate to it and replaced the steel with synthetic winch line.

 

[96coal449]

@Jehinten is this a completed project? Super sweet score!

 

[Muggs]

* Per Greg Good, from a TCIA article here: “We don’t recommend using the winch component of the GRCS in extreme negative-rigging situations, but it has been tested in negative-rigging situations where a ¾-inch lowering line (20,000-pound tensile) repeatedly failed with no damage to the winch."

Talk about confusing recommendations.

I don't believe in this notion that the capstan winch is this delicate thing that we need to be careful with. I think it can handle anything you throw at it and then some. Up to and including shock-loading 3/4" double braid to failure. Not that I would ever do that. I don't even own a 3/4" rope. I generally go out of my way to avoid big negative rigging. But it's good to know that it can handle anything. I think if there's any weakness on the GRCS, it's the mounting plate itself. I don't like how it mounts to the tree. I'm working on a mounting mod for mine.

 

[flushcut]

10:1 safety factor thus 2000lbs. Plus breaking 3/4” is a hella big chunk. I’m flopping the log in that size range not rigging it down.

 

[96coal449]

if there's any weakness on the GRCS, it's the mounting plate itself. I don't like how it mounts to the tree. I'm working on a mounting mod for mine

Please.....thread on this.
TIA

 

[Bart_]

There was a thread a long time ago showing failed internal pawls or teeth, possibly a repeat the heavy load enough times and it will fail sooner sort of thing.

In Daniel's dynamometer video (this vid didn't match my recollection exactly maybe here's another one too?) the configuration aside from the redirect wasn't quite single rigid vertical spar as is often tested giving a typical 5Gs worst snubbed case. The peak force occurs for a fraction of a second (snubbed) so you can figure that energy absorption of shock contributes to lowering the peak. Aside from rope stretch, there's sling shift at the tip, rope shift on the log, sling shift at the porty (or redirect) and in Daniel's redirect case straightening of the rope catenary. He indicated 3Gs peak but the rope load at the log goes through two tension ratios before the gauge - x1.1 to 1.2 at the 180 degree rig tip pulley and we'll say x 1.1 at the redirect pulley so 1.1 x 1.1 x 3Gs = 3.63 Gs lower value or 1.2 x 1.1 x 3Gs = 3.96 Gs higher value. e.g. 500 lb log at 4Gs = 2000 lbs in rope next to log even though the dial shows 1500 lbs peak (3 Gs)

food for thought. some credit goes to chapter 8 HSE report -ve rigging which addresses the standard formulas too like Blair's. Evo, in Blair's video the groundie took up about 1ft slack only (?) which is a smaller portion of the log CofG's vertical travel? i.e. not practically a big contributor, but some difference

 

[evo]

There was a thread a long time ago showing failed internal pawls or teeth, possibly a repeat the heavy load enough times and it will fail sooner sort of thing.

In Daniel's dynamometer video (this vid didn't match my recollection exactly maybe here's another one too?) the configuration aside from the redirect wasn't quite single rigid vertical spar as is often tested giving a typical 5Gs worst snubbed case. The peak force occurs for a fraction of a second (snubbed) so you can figure that energy absorption of shock contributes to lowering the peak. Aside from rope stretch, there's sling shift at the tip, rope shift on the log, sling shift at the porty (or redirect) and in Daniel's redirect case straightening of the rope catenary. He indicated 3Gs peak but the rope load at the log goes through two tension ratios before the gauge - x1.1 to 1.2 at the 180 degree rig tip pulley and we'll say x 1.1 at the redirect pulley so 1.1 x 1.1 x 3Gs = 3.63 Gs lower value or 1.2 x 1.1 x 3Gs = 3.96 Gs higher value. e.g. 500 lb log at 4Gs = 2000 lbs in rope next to log even though the dial shows 1500 lbs peak (3 Gs)

food for thought. some credit goes to chapter 8 HSE report -ve rigging which addresses the standard formulas too like Blair's. Evo, in Blair's video the groundie took up about 1ft slack only (?) which is a smaller portion of the log CofG's vertical travel? i.e. not practically a big contributor, but some difference

got a link to that video?

 

[Daniel]

In Daniel's dynamometer video (this vid didn't match my recollection exactly maybe here's another one too?) the configuration aside from the redirect wasn't quite single rigid vertical spar as is often tested giving a typical 5Gs worst snubbed case. The peak force occurs for a fraction of a second (snubbed) so you can figure that energy absorption of shock contributes to lowering the peak. Aside from rope stretch, there's sling shift at the tip, rope shift on the log, sling shift at the porty (or redirect) and in Daniel's redirect case straightening of the rope catenary. He indicated 3Gs peak but the rope load at the log goes through two tension ratios before the gauge - x1.1 to 1.2 at the 180 degree rig tip pulley and we'll say x 1.1 at the redirect pulley so 1.1 x 1.1 x 3Gs = 3.63 Gs lower value or 1.2 x 1.1 x 3Gs = 3.96 Gs higher value. e.g. 500 lb log at 4Gs = 2000 lbs in rope next to log even though the dial shows 1500 lbs peak (3 Gs)

good info thanks.. the thought never occured to me.

If I didn't have a mini, I would use it semi-regularly.

I've got a Simpson capstan winch for a few upcoming hike-in hazard trees.

Can't even remember the last time I used it. I'd rather set a redirect at the base of the tree and use a porty on the loader... waving the fingers is a lot easier and faster than cranking on that handle.. and most of the GRCS work on YT videos looks like a total waste of time, when gravity ALWAYS WORKS. Lot of that tp tying is completely unneccessary and ads a dimesion of risk to the climber with trivial benefits..

 

[96coal449]

and most of the GRCS work on YT videos looks like a total waste of time, when gravity ALWAYS WORKS.

 

[Muggs]

@Daniel what does YouTube have to do with anything? Most of the best people in tree work, or any line of work, have next to nothing going on online. They do great work for the intrinsic value and satisfaction that the work provides them. They are craftsmen, and the only people who get to see their work are the couple guys who happen to be there that day.

 

[Daniel]

This is an example of rigging that could easily have been done using gravity. all that top notching and fooling around with the cut is just stupid... It was even worse before he edited out all the parts where the limbs were too big to fit in the yard...

and this one too.. a total waste of time when a rip cut and good tie off would have been faster and much easier

This is what happens when you know how to use gravity. All rigging was hand tightened with Port-a-wrap only (you're not even close @Muggs )

The big oak limb was touching and growing into the top of the large Jap maple.. No GRCS required

https://youtu.be/OvPdciezA50?si=ftz26ATeQ2Vif75q&t=205

Here's one we lifted off the roof with rigging and a truck to do the pulling. GRCS would have been a total waste of time...

https://youtu.be/HM52FXtF9LY?si=NEfRQvAeAQaT7Dz1&t=97

 

[flushcut]

@Daniel what does YouTube have to do with anything? Most of the best people in tree work, or any line of work, have next to nothing going on online. They do great work for the intrinsic value and satisfaction that the work provides them. They are craftsmen, and the only people who get to see their work are the couple guys who happen to be there that day.

How dare you ignore the old retired people who pull up a lawn chair and stare at you for the entire job.
Some of my best tree work was done in front of an elderly man who may or may not have actually been able to see my work, cataracts.

 

[Bendroctanus]

This is an example of rigging that could easily have been done using gravity. all that top notching and fooling around with the cut is just stupid... It was even worse before he edited out all the parts where the limbs were too big to fit in the yard...

and this one too.. a total waste of time when a rip cut and good tie off would have been faster and much easier

This is what happens when you know how to use gravity. All rigging was hand tightened with Port-a-wrap only (you're not even close @Muggs )

The big oak limb was touching and growing into the top of the large Jap maple.. No GRCS required

https://youtu.be/OvPdciezA50?si=ftz26ATeQ2Vif75q&t=205

Here's one we lifted off the roof with rigging and a truck to do the pulling. GRCS would have been a total waste of time...

https://youtu.be/HM52FXtF9LY?si=NEfRQvAeAQaT7Dz1&t=97

No, the GRCS was not required, but it would have allowed you to place a little more control on those butts. More than one way to skin a cat. Butt, what do I know…

 

[TheTreeSpyder]

On overhead rig of the long , some skinnier near horizontals would favor tighten hard by hand(including climber 2/1 and climber sweat/swig), hitchpoint a bit hinge side of CoG; and use the length as a lever stretch rope hard(from the distance of drift on hinge) as lay load into rope, pre-tightening rope even more until line tension to equal or about the load itself. The longer the lever between hitchpoint and hinge pivot, the greater tightening per degree of drift down.
.
Make it handle very lightly on hinge and less tear off shock because most of the weight already transferred to rope by then. At tearoff want rope angle pulling away from climber.
.
Use beast's own length and weight against it, and the positive tip weight to make it steer itself into hole to ground. Line up the pool shot correctly and kinda like a martial art, the limb can beat itself; configure it's own graceful demise.