Auto block vs rope for friction hitch backup for an ATC?

[razorsharptokill]

I am very new to saddle hunting so bare with me. What (if any) are the advantages or disadvantages of using a hollow autoblock cord vs a rope for backing up a belay device?

 

[Marmuzz]

One advantage of the Hollow Block is it can be easier to tie a quick autoblock hitch, insofar that you don’t have to first tie a bulky double fisherman’s to connect the cord ends and it’s somewhat simpler to rapidly throw on the rappel line. A disadvantage is you have less hitch options with a closed loop cord; whereas if you wanted to experiment with eye-to-eye style hitches, you can with a length of cord. Not a major deal as a backup below an ATC, but something to consider nevertheless.

 

[Iron_llama]

A lot of people like the Hollowblock because it's very soft cordage, and easy to quickly tie one-handed. I, personally, don't use it because (as I understand it) it's not rated for primary life support. It's intended as a backup - think "emergency brake" or "failsafe" - in a system in which all the other components are rated for primary life support, and is entirely appropriate in that application. Hollowblock comes from the rock climbing world and is discussed there in more depth and detail than among saddle hunters. Read up on what rock climbers say about "third hand" and "rappel backup".

I'm entirely happy to admit here that I don't know nearly as much on this topic as a lot of others so if I'm off-base please correct me.

 

[Samcirrus]

I am very new to saddle hunting so bare with me. What (if any) are the advantages or disadvantages of using a hollow autoblock cord vs a rope for backing up a belay device?

You don't need an autoblock at all. A good hitch cord like the sterling 7mm or trc 6mm will be more than adequate for all 40' rappel. Experiment and find a hitch you like that breaks under load (not a prusik! ) and that'll do just fine for hunting and time to rappel.

 

[Iron_llama]

To expand... I'm a 1-stick climber. I climb on my rappel line with a friction hitch (last season used both Sticht and WLR) and tend out the slack as I climb. No belay device in use during this evolution. At height I switch my weight to a short tether, tend slack into my rappel line, and install a figure-8 above my friction hitch. At this point, my climbing hitch becomes my rappel backup, negating any need for an autoblock. Other 1-stickers use mechanical ascenders and put their friction hitch backup above the device. When I descend I switch from my short tether to my rappel line and head down the tree. The right answer for you is probably going to depend on how you climb, how you capture progress, and other similar factors. If you SRT on a Blake's, you probably won't use a backup hitch at all, for example.

 

[CZMark]

I've used a Hollowblock with an ATC for years. It's soft, has sewn ends, is the perfect length, and deploys easily. Buy one, you won't regret it.

 

[bfriendly]

THe only thing I would recommend not doing, is tying anything in the field except a stopper knot somewhere you may not have needed in the first place. I switch over to a rappel rope which already has a prussik or Michoacán hitch attached. I connect that hitch to a lineman’s loop, below my ATC. That hitch is simply a brake on he ATC. It never really loads and even a prussik will break easily……I do prefer the Michoacán though. I tend it out to the side(simultaneously tending the ATC) and it’s nice and smooth, let go and I stop, hands free to remove stick, platform. Keeping the hitch on my rappel rope has become second nature. When I wind my rope up, I slide the hitch up the rope(inspecting rope as I go) to the delta link end. Make sure the length of any hitch below your ATC is far enough below that it cannot reach the ATC……You do not want that hitch to get inside the ATC.

 

[razorsharptokill]

Thanks guys. Tring to visualize all that has been written above.

 

[Craft518]

You don't need an autoblock at all. A good hitch cord like the sterling 7mm or trc 6mm will be more than adequate for all 40' rappel. Experiment and find a hitch you like that breaks under load (not a prusik! ) and that'll do just fine for hunting and time to rappel.

Can you explain why not a prusik?

 

[Marmuzz]

Can you explain why not a prusik?

A prusik bites very hard and doesn’t release easily under load, which is needed when on rappel. Other hitches like a Klemheist work and release much better for rappels.

 

[John RB]

I am very new to saddle hunting so bare with me. What (if any) are the advantages or disadvantages of using a hollow autoblock cord vs a rope for backing up a belay device?

Your question was about using a hollow block vs a cord as a backup for a rappel (which is more accurate term than 'belay'). First, a hollow block is a type of cordage which is designed to bend really well and to maximize the surface area on the rope. They are typically not sheathed and made out of heat resistant and extremely strong fibers. You can buy hollow block in a length OR in a loop, typically referred to as a Prusik loop. Some of the responses seem to assume that hollow block = a loop, but that's not accurate. I buy it in 30ft lengths.

No matter whether you have a loop or a length of cord, when I did an apples to apples comparison, side by side, using the same friction hitch, a hollow block will generally be:
1. a better grab
2. Stickier and a little harder to move.
3. Harder to break under load. There are times we need to do so. I will put my video link at the bottom.

Now, regarding the use of a LOOP, rather than a length of cord.

1. A loop can only be used for a small minority of the set of friction hitches. Prusik, Autoblock, Klemheist, Hedden, Bachmann (and a few others including a new one I am releasing very soon. )
2. Almost all of the more advanced hitches require either an "eye to eye" or a length of cord. The cord needs to take load on both strands, so we have to either terminate it with 2 knots on each end tied to our biner, or connect them using a bend. I recommend Hunter's Bend and have a video on my JRB Tree Climbing Channel if ya need it.
3. IF you can leave your friction hitch on the rope, you can use an advanced hitch for optimum performance. IF you need to take it off every time in order to retrieve your rope, you'll want something really easy to tie OR you'll wanna consider a different retrievable anchor which doesn't require removal.

I should have the new knot published in a day or so... i prefer it over the 5 I mentioned above and can tie it blindfolded in seconds. Its a good backup because it's more easily broken under load. I personally do not like sewn loops. I would always prefer to tie what I need.

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[Samcirrus]

Can you explain why not a prusik?

Sure. A prusik to me is an "insurance policy" hitch that is so solid its the go to hitch for all manufacturers because it won't fail....but it won't release either. IMO the reality is that its way too grippy to be useful and is very hard to break under load. Almost anything else is easier to manipulate and actually be a movable hitch.
My current favorites are the JRB ascender and the Knut.

 

[John RB]

Sure. A prusik to me is an "insurance policy" hitch that is so solid its the go to hitch for all manufacturers because it won't fail....but it won't release either. IMO the reality is that its way too grippy to be useful and is very hard to break under load. Almost anything else is easier to manipulate and actually be a movable hitch.
My current favorites are the JRB ascender and the Knut.

Gotta agree 100%. We got so many climbers who are climbing with excessive slack. And so when the stick disappears and we fall 3ft on a Prusik and it holds and saves our life, we'll be dangling from an unbreakable knot. I prefer to never allow slack in AND use a breakable knot. I have been working on this and climbing on it thru the winter. I just uploaded the video moments ago. It's not as easy as the JRB Ascender to break but 10x easier to tie.

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