X Rigging Rings, thoughts

[Wooden Hand]

Pete, the largest ring can comfortably negative block 300kg pieces. This is to your discretion of course and when used to pulleys it seems anti-theoretical but i've dropped many tonnes on the lagest ring and am happy to drop many more.

[scotspine1]

I agree Pete on the catching issue.

 

There's still a question mark for me on the X rings for those situations where you have to snatch a decent sized section of timber or a big branch, over a roof etc. A situation where you can't let it run.

 

In this scenario the amount of force on the rope between the section of timber and the x rigging rings would be much greater compared with a rigging block/pulley because a pulley allows the force in the rope to be dissipated along the entire length of the line down to the friction device. With the X rings the majority of the force is being taken by that short length between the timber/branch and the X rings.

[Wooden Hand]

Zelkova serrata.

[Wooden Hand]

I wonder what the friction percentage is and how much working rope you would lose? Anyway, for critical situations you always modify the usual plan.

[scotspine1]

I wonder what the friction percentage is and how much working rope you would lose? Anyway, for critical situations you always modify the usual plan.

 

If you think about how the rigging line flattens out on the rings under load in the same way it flattens on a portwrap/drum brake etc - when you catch/snatch a section of timber or a big branch the effect of the X rings is to act like a brake so percentage wise the amount of force being applied to the section of rope between the timber and the rings is much greater than the force being applied from the x rings to the lowering device. This is one of the reasons why pulleys were introduced into our work in the first place, to allow the force to be dissipated along the entire length of the line.

 

Anyone whose done a lot of big natural crotch rigging will know exactly what I'm talking about.

 

It's not about the strength of the X rings, its about how the friction created by the rings affects the strength of the rigging line when you have to catch sections of timber or big branches/tops.

[Robert_S]

An expensive topping down strop, talk about re inventing the wheel...

[Wooden Hand]

I hear you Tim, like I said, plans can be modified. Catching big tops is an unusual situation. If you want to catch big tops then you best spread force through as much rope as possible.

You cant say that 1 side of the ring would see more force than the other because it depends on length of rope and what ever you have going in in the system, additional MA one side and additional friction the other for example. Have you used the rings? They are intuitive.

The rings are far closer to a pulley than natural crotching, if I need compare.

[born2trot]

I hear you Tim, like I said, plans can be modified. Catching big tops is an unusual situation. If you want to catch big tops then you best spread force through as much rope as possible.

You cant say that 1 side of the ring would see more force than the other because it depends on length of rope and what ever you have going in in the system, additional MA one side and additional friction the other for example. Have you used the rings? They are intuitive.

The rings are far closer to a pulley than natural crotching, if I need compare.

 

Surely the whole point is that it is more attune to natural crotching though ? If it's the same as a pulley where's the benefit then ?

[Wooden Hand]

What whole point?

If natural crotching is 100% friction, a pulley 0% and carabiner around 50% then the hard anodizing on the x rings will be somewhere between 20-30%.

[Gerbutt]

They do look good but I don't think my LOLER inspector would be happy to pass them! Am I right in thinking that the x ring is from the US so no ticket of conformity? He won't pass my HH for this reason.