rope glazing from a porta wrap??

[Johny Walker]

You don't need Cs41 to be competent at rigging, in the same way that having cs39 doesn't make you a decent climber.

 

I got sent on my 41 a while back as a formality. I learnt virtually nothing I hadn't already figured out with experience or common sense.

 

 

[justo7]

What I meant was its a good way to get some basic info, I didn't mean or criticise anyone who rigs without it. I started rigging well before I did cs41. Probably I need to sharpen up my English to explain what I mean better

[carlos]

no i havent done cs 41 woudnt mind though, still ones always learning all the time, i think the problem may of been letting a large lump run too quick, not sure though, the upshot is the boss has bought a mega new bollard so i hope we wont see any more glazed ropes!

thanks for the input guys

carl

[CBiscuit]

I think it has to do with the heat capacity of the device. I glazed mine the other day with probably an 800 pound piece. I know everyone will say that will overload the WLL of the port a wrap while negative rigging. But!! If you let it run! It greatly reduces the load on the rigging. In this scenario we had a much longer run than usual, probably 45 feet. A puff of smoke came off the porto. Oops. So I guess I'm arguing both ways. The limit of the device shows itself by being overloaded, or scorching your rope. My plan to increase the capacity of my portowrap is to start using a safe block while negative rigging. Take some of the load off the porty

[Dan Maynard]

Yes, heat capacity can be the limit. The piece being lowered loses gravitational energy (mass x distance lowered) and this energy mostly ends up as heat in the portawrap and the rope. Lowering a big piece a long way will heat the bollard, letting it run lowers the peak force but the same amount of energy has to be dissipated overall.

 

Safebloc will share some of the energy, and being aluminium helps it spread the heat away from the surface.

[Ledburyjosh]

Ensure you you do as much as possible to prevent the rope rubbing on the tree stem, that can also glaze ropes.

 

But most likely the small capstan doesn't take long to heat up to a point it melt ropes. Larger bollards like the stein 3001 or GRCS will take longer to heat up so have higher capacity in that way.

Steel also takes longer to heat, but retains that heat, aluminium heats quickly but also disapates heat quicker. 

So if you send large pieces or lower a long way on a small steel capstan that heat is going to build and then hang around.