Nice score on a rope at auction...maybe?

[pdqdl]

I stumbled over a vague listing of a 600' rope in an online auction. So I took a gamble and got it for $115 US dollars.

I have since discovered that it is 1/2" kernmantle rope made by Sterling: 1/2" HTP, a rope with very low stretch and a mean breaking strength of over 9000 lbs. This rope is the firmest braided rope I have ever handled and it ties knots only with a good bit of effort. The rope is so hard and stiff that you could use it like a club in a street fight. The loops of any knot you tie in it are rather difficult to pull tight and set like most of the ropes I am familiar with.

The rope is a bit smudged on one end of the rope, as though it has been used only once. Otherwise, it looks and feels brand new. So...did I do well on the purchase, and what would you use this rope for?

 

[Pelorus]

Speedline application, mebbe.
I'm not at all fond of rope that doesn't hold a knot well.

 

[pdqdl]

Speedline would be cool, but I don't see a need for a 600 footer. I'm sure it will get cut up as needed in the end, anyway.

I can't say how well it holds a knot; probably pretty well. It's just that the rope is so stiff that the knot does not seem to snug up like a softer rope will.

Example: a double fisherman's loop in this rope holds great under the meager load I can pull on it with my hands. This is my preferred knot for attaching to a carabiner, because it holds so well and pulls out easily when you remove the carabiner. Unlike using a softer rope, you can't hope to pull out the loop when the carabiner is removed, and the knot remains loose looking, even though it isn't.

I did read a mountain-climbing text that stated that knots in low-stretch kernmantle rope should leave a longer tail on the knots than usual. Apparently, the longer tail serves the same purpose as dressing it properly on a softer rope.

 

[squad143]

We use PMI 1/2" kernmantle for high angle rescue work on the fire department. It is extremely stiff when new, but does work in a little when used a bit.
I find it a bit too stiff for treework. I have a 600' spool as well that I use for speed lining as well as several 200' lengths that get used as tag lines.

For rescue work we primarily use the figure 8 knot and vibrations of the figure 8. It's always backed up with a safety knot (fisherman) with 3-6" of tail remaining.

 

[imagineero]

Don't use it for climbing on that's for sure. Ropes like that are used for industrial access, abseiling and canyoning/caving. The low stretch is great for long ascents, but deadly for climbing. Stretch is what absorbs minor slips/falls or other impacts and the rope takes the shock off the anchor and off you. Static ropes have a very low cycles to failure if given dynamic loading, and the impact the rope sees with even minor dynamic loading is far greater than a rope with some stretch sees.

It's suitable for speedlining, industrial access, long freehanging ascents, tag line. I wouldn't use it even for light rigging, but if you have a GRCS you can use it as a lifting rope. Just be sure and not to go negative blocking on it.

 

[ATH]

Not a rigging line (needs to have give for rigging). Not a life line (I'd never trust a used/possibly used/unknown history rope for life line).

 

[pro94lt]

Them auctions get the best of us

 

[pdqdl]

Don't use it for climbing on that's for sure. Ropes like that are used for industrial access, abseiling and canyoning/caving. The low stretch is great for long ascents, but deadly for climbing. Stretch is what absorbs minor slips/falls or other impacts and the rope takes the shock off the anchor and off you. Static ropes have a very low cycles to failure if given dynamic loading, and the impact the rope sees with even minor dynamic loading is far greater than a rope with some stretch sees.

It's suitable for speedlining, industrial access, long freehanging ascents, tag line. I wouldn't use it even for light rigging, but if you have a GRCS you can use it as a lifting rope. Just be sure and not to go negative blocking on it.

It doesn't feel right for climbing, but I thought some of you SRT guys might use it for that. Yep, I know about the low stretch issues. I was thinking that it might work well on my capstan rope winch, although it might be a bit stiff to wrap and bind on the capstan.

What would be "negative blocking"?

 

[imagineero]

Might be a good rope on the capstan for sure. Just add an extra turn off needed for some more bite.

Negative blocking/rigging is just a fancy term for blocking down, when the pulley is below the block you're cutting. Because the block falls some distance before the slack takes up, the loads on the rope are very severe. About 4-5x the load that the rope would see in a normal rigging situation where the pills is above the piece being cut.

 

[Pelorus]

My experience with hard rope on capstan winches has been lousy. Once the slack is taken out, the winch maxes out very quickly (not enough elasticity in the rope), and the bigger problem is being able to get enough wraps on the drum to get it a good pull, period. In the winter with a stiff rope with any snow on it; forget it.

 

[pdqdl]

Shucks, I don't think I have ever blocked anything down unless it was the main trunk and we were rigged below the piece coming down. Yep, that breaks rope in a hurry. Very few of our trees have branches so big that natural crotching causes rope damage. You probably work with those huge eucalyptus trees, don't you?

I kinda figured that the hard rope would bite poorly on the capstan. This rope is so hard that I imagine that it will be tougher to pull around the guides. On the other hand, the kernmantle cover is pretty smooth and has a rather high melting point. It might be pretty tough with all the friction.