Melted rigging rope

[pd_denmark]

We are two colleagues who has just melted two bull rope rigging ropes in two months. The first rope was a 14mm bull rope and the second rope was a brand new 16mm bull rope 7,5 ton tensile strength.

The second rope melted today when we rigged a 330 kg chunk.

At big jobs we always use a pulley and a large steel rigging device. Always the same setup.

We have no idea why we have burned two ropes lately. They are melted on around 10 meters and more than 20-30% of the surface.

The ground guy was letting the pieces run to minimize shock load.

 

Could it be the poor heat transportation properties of steel in the device?

And / or could it be build up heat after rigging several big chunks right after another?

 

We really hope that someone can help us out so the problem doesn't continue :-/

 

We have been rigging big stuff for many years on the same device and have never melted a rope after just one big lovering. To me it's very odd.

Looking forward to some replies :-)

 

Climb safe.

[pd_denmark]

The first half day, we rigged big limbs out and let them run fast to the ground without any heat damage to the rope. But maybe the difference between the chunks and the branches is that we do the chunks right after another - there is always some waiting time after rigging a big limb when the ground crew cuts it up etc and therefore the device can cool off before the next run....

[arbogrunt]

I've only ever seen this with folk using natural crotch rigging and/or taking wraps around the trunk...I'd be interested to know why this happened..what make of rope were you using mate?

[Steve Bullman]

Got any pics of the rope and the hardware you're using?

[pd_denmark]

Pics will be posted tomorrow :-)

[pd_denmark]

 

 

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[pd_denmark]

 

 

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[pd_denmark]

 

10 meters where melted like this.

 

 

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[crackoff]

not sure if it's just the light,??? but your lowering devise looks like it needs a good clean?

 

If so, this could easily cause a lot of "sticky" friction, that could in theory burn your ropes???

 

Just an idea though.

[Pete Mctree]

What condition is the ISC block in? Does it still turn under heavy loading?