Rope grab recommendations for rigging

Flying~Squirrel

Flying~Squirrel

Participating member
Location
VT/NH
I'd like to hear recommendations for the best rope grab device to use as a way to attach a set of 4s to a rigging line for pretentioning and lifting, then quickly be removed to lower from a friction device. It would also get used as a way to extend a winch line for repeated advancement pulls.

The traits I'm hoping for are:
- quick on and off
- smooth easy progress
- ability to release friction
- maximized breaking strength of the rope being grabbed
+ Maybe having an integrated pulley, for easy advancement of the slacked system. This is less necessary, and may not be worth the complexity.

I've mostly been using a prussic, but it's not that quick on and off and can be a real bastard to quickly reset for another length of pull. It does check the other boxes, and it's cheap and easy to tweak your set up.

I've used a handled ascender, but being unable to smoothly ease tension can lead to trouble.

I've thought about using a lanyard style rope grab, but I have little experience with these and don't think they are easy on / off. Maybe I am wrong.
 
At least one rope grab has a quick release pin for easy on off the rope. The SS unit used on the Wraptor and elsewhere. I would feel good about using up to 1500 lb pull. I have one on a Masdam rope puller and the Masdam itself goes to full slip at about 1200 to 1500lb resistance.
 
Merle Nelson said:
At least one rope grab has a quick release pin for easy on off the rope. The SS unit used on the Wraptor and elsewhere. I would feel good about using up to 1500 lb pull. I have one on a Masdam rope puller and the Masdam itself goes to full slip at about 1200 to 1500lb resistance.
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that would be the Gibbs or similar, which do not release under load.
 
Gibs or a canned device that has a concave rope channel and flatter cam. Others pinch the rope and cause failures at fairly low loads in any rigging setup that may experience a shock load.
Petzl’s older micro grab was a ok one with a 1/2 limit. Those will slip before breaking the line (done it more than once).

100% nothing toothed.

Prussiks are hard to beat and somewhat have a failsafe overload feature of slipping.
Look at the load rating for slippage on the grabs, most will are suppose to slip well under 5:1 one person input forces.

Personally I shun rope grabs for these applications. Never used one but a petzl shunt is suppose to have a slip before parting the line feature.

Looks like there are a couple of easy on/off still out there being made.
Smc has another one.
www.treestuff.com

Rock Exotica RockGrab MIL

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Is there any compendium or chart of cordage plus rope combos slippage force for common hitch knots? I'm pretty sure there have been dribs and drabs of selected combinations in vids by enthusiastic pull testers through the years IIRC.
 
Grcs or whatnot do all of that much easier for pretension and lift (we used to do 4:1 with prussic) and cleaner too. The rope jack seems to have its place too (not sure what cams it uses) and cheaper/lighter. We use prussics for 4:1 pull when a machine can't get there and like the failsafe of slipping too.
 
How about a rescue 8 and clip in with a steel carabiner? I'm not sure how well they maintain rope strength.

2nd the ropejack, thats my personal choice for hand pulling, miniskid to pull when it can get in position
 
I have a Rockgrab 90 0.625 (the big one 13-16mm) that I modified with a quick-release pin to use for my fiddle block. It works alright. But I usually forget it in my bags of extra gear and just end up using a 3/2 schwabisch on 12mm prusik. Tried and true.
 
Serf Life said:
Grcs or whatnot do all of that much easier for pretension and lift (we used to do 4:1 with prussic) and cleaner too. The rope jack seems to have its place too (not sure what cams it uses) and cheaper/lighter. We use prussics for 4:1 pull when a machine can't get there and like the failsafe of slipping too.
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I'd love a GRCS and have used them in past lives to dramatic effect, but now I'm a solo brokey working out of a pick up truck, so fiddle blocks it is.

I'm not complaining, I really enjoy getting efficient with simple machines. To that end, this thread had me thinking that I really just need to dial in the prussic variations for my use cases and optimize. Rope is cheap and wonderful. I'll also try to find a second hand rope grab to play around with, because it's a ubiquitous tool that I've mostly side stepped.

To those gear inventors out there: please make note that there's a small gap in the market for a mechanical rigging device that holds when you pull and glides when you push, and is easy to put on and hard to break. Basically a big bad rope runner. And keep in mind you'll only sell it to people who can't afford a GRCS, so make it cheap!
 
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Thinking outside the box a bit with this suggestion but what about repurposing a foot ascender like the Notch/Harken Jet step? Might have to get creative with how to attach a pulley to it but as far as easy on/off, gentle interface camming devices, I don't see how it wouldn't work.
 
Phil said:
Thinking outside the box a bit with this suggestion but what about repurposing a foot ascender like the Notch/Harken Jet step? Might have to get creative with how to attach a pulley to it but as far as easy on/off, gentle interface camming devices, I don't see how it wouldn't work.
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Does it come off under load? I have definitely had it slip off, but I always wrote it off to movements when it was not loaded.
 
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