UKC

Hey guys,

When retrieving very spread out gear or traversing above difficult routes to set up a top-rope, I have very occasionally tied a figure 8 knot to my harness with one end of the rope strand and tied the other strand with a grigri to the harness. 

I was wondering if this is an "acceptable" method. I am aware that there is more pressure on the rope because instead of a fixed point of rope around the anchor abseiling normally , the entire rope runs through the fixed anchor.

Thanks in advance!

It's a pretty standard way to achieve a retrievable abseil with just a single rope and a grigri. I use it a lot when bolting and cleaning routes.

Two important considerations. The first is obvious but critical - there should be no chance of the rope through the anchor touching any slings or other tat, so fixed rings and karabiners only. The second is to be aware of the possibility that your waist knot might get in the way of the operation of the grigri if you let go for any reason. I've never had the grigri not lock up properly so I don't know how likely that would be, but quite often the knot might inhibit the handle from closing fully (after the cam is engaged) so I'm always very careful to make sure it gets closed fully each time the handle is released.

The third consideration is that the rope can't run over any sharp edges.

You could also tie a couple of stopper knots in the trailing rope - overhand with a big loop. Then if the gri gri fails to catch for whatever reason you would be stopped by the knot.

What's wrong with a normal ATC abseil on two strands of rope and a prussik backup?

If one side of the rope has gear on it then you can quickdraw that strand of rope to your harness to keep yourself in line.

Thanks for the advice!

Much appreciated!!

The method  you describe for descending a route is safe enough. However, if the rope runs directly through the bolts it will abrade them. This is also why top-roping directly from the anchor is frowned upon. If you thread the rope through a couple of your own carabiners they will take the abrasion and the anchor will last longer.

I agree with stefan. If you want to finish up at the top then gri gri and rope through your own carabiners is a quick easy option and safe if you tie a few back up knots in the trailing rope.

If you're just going back to the bottom then atc belay device or similar with a backup prussik attached to both strands is the best for limiting wear on fixed gear.

That is true, but it's no worse in that respect than the last person on a route cleaning the bolts and being lowered by their partner, which is common practice. If your recommendation is to be followed, shouldn't we be consistent; i.e. last person down always abseils?

I agree, we should be consistent and the last one should abseil down.

How would you do that with a GriGri though?
 

I would use a munter hitch...

A grigri is not the best for this type of abseil as it's only single rope where as the likes of an ATC is dule rope there for you can ab off the rope dubled up and put very low ware in the anchor

As John Arran says, it's a pretty standard way of doing it, but there are potential issues such as wear and it's always a bit awkward with the Grigri handle.

An alternative method is to :

-thread the rope through the lower off to the halfway point

- tie a figure of eight on one side of the halfway point/ anchor

- attach a screwgate to the figure of eight and clip to the other "down" rope.

You can now descend with a Grigri on the "down" rope, and retrieve the rope by pulling the other end with the figure of eight on it. This removes most of the problems outlined by various posters above.. with the obvious caveat that you need to be clear what you are doing and practice this at ground level first! 

Not on my ropes!

It's a sports route with a lower off so there's a good chance that a belay device for two ropes wouldn't be available.
As for wear on the lower off, etc. that is primarily caused by excessive top roping by groups led by Instructors that either don't know what they're doing or don't care as they won't be the ones paying to replace them. 
The technique described in the OP is the best method if using a GriGri for abseiling, but with the caveat that you're aware of the moving rope cutting through static nylon and/or dislodging rocks, etc.

What are you basing this assertion on? Are you sure this isn't a bit of anti-commercial groups prejudice? In my experience, professional instructors tend to be aware of this issue, and usually set up top ropes appropriately. I can't be certain, of course - it would be very difficult to come up with evidence - but I strongly suspect the main culprits are recreational climbers, especially small groups of friends.

You are really making things hard for your self. Use bug and prussic.