Micro Rack Lock Off

[Eric Wright]

Warning: Long Post with several images... some depict what not to do (IMHO).

I've been forming an opinion about different ways of locking off with a closed frame micro rack that has a single hyperbar. I'm wondering if any of you would like to weigh in as well. Basically, I'm trying to decide on what I feel most comfortable with in terms of both full and soft locks. All of these locks are described in the literature, the instructions that came with my rack (a BMS) or were shown to me/observed in use by some other caver. I've hung on all of them (a foot or two from the deck). I'll go through them in order giving my thoughts on them, but like I said, I'm hoping for some input.

BMS refers to this as a "Soft Lock" in the paperwork that comes with their micro-rack. This paperwork can be found here. Here is a photograph of the same thing:


I've seen a variation on this one as well. The difference is to bring the tail over the top bar between the bolts first and then bring a bight through the rack frame (under the bars) and then loop it with a twist over the hyperbar.
It looks like this:


Of these, I think I prefer the first because your rope will always end up in the high friction position over the hyperbar as you are unlocking it. It ends up between the bolts with the second version.

Question. BMS calls this a soft lock. It seems kind of like a full lock to me. Is there more you should do if you want to lock off more securely than this? The only thing I can think of would be to tie off afterwards by bringing a bight to the top of the frame and tying it around the rope. This is in some ways similar to the full lock off pictured in "On Rope" on page 123 (figure 5-54 B).

In any case it would look like this:

Is it overkill, or is it necessary?

Other Variations: These come from "Alpine Caving Techniques" (more or less) from the discussion on locking off with a hyperbar on pages 146-147. Please note that their description seems to be tailored more to a j-frame rack with a hyperbar. Start with a soft lock like this:



And then fiinish by passing a bight in the tail around the back of the rack, through the frame (under the bars), and then loop it over the hyperbar with a half twist. It should look like this:


This seems ok, but I was able to partially unlatch one of the bars when practicing a changeover using this lock. It happened where the bight passes around the left side of the rack before coming back through the frame and over the hyperbar. I noticed it after placing the rack on the rope, removing the croll, and partially weighting the rack. It only happened once, and I have not been able to reproduce it.

I was shown a variation on this lock that involves passing the bight of rope through the locking carabiner instead of the rack frame. It looks like this:


One thing I noticed about this lock is that while it seems to work ok when you are already on rappel and the rope is loaded, it strikes me as a really awkward one to use during a changeover. This is because you are not weighting the rack when you are installing it on the rope. This makes it possible for the carabiner to get bunched up with the bars when you install the rack and lock off. It looks like this:

Two things I don't like about it: (1) you could be running a little risk of cross-loading your carabiner if you aren't careful (2) When you weight the rack, the carabiner has to pull the rope back down to the bottom of the rack frame. Sometimes, this isn't a very smooth motion. For this reason, I'm hesitant to use this lock with a micro-rack.

So I guess my tentative preference would be to use the BMS "soft-lock". What about tying it off? Is this ever necessary? What would you use?

[fuzzy-hair-man]

I agree with you I'd use the BMS method and it is what we use with our U frame racks (no hyper bar). We don't tie off to the rope above the rack, I say it's overkill unless you were particularly nervy or going to be stopped for a long time or doing acrobatics that may accidentally release the lock.

Given the choice I'd not use the method where you bring the tail of the rope up between the rack and the rope above the rack, from what I have heard it can become trapped and difficult to release from that position. However as you mention with J Frame racks etc it may be (if you don't have a spare carabiner?) unavoidable.

The method where you push a bight through the attachment carabiner is useful if you have either a stiff rope and/or small frame rack and it is difficult to thread a bight through the rack frame below the bars (some might say this means the rack is too short).
I prefer to thread it through the rack frame however as I figure pushing the rope in and out may cause the carabiner screw to undo so this method is best avoided if at all possible but it is worth keeping in mind for difficult conditions.

I notice in your last photo the gate of your attachment carabiner is facing away from you, my preference is to have it facing you this way it is easy to see if it comes undone. It also means difficult lips etc aren't going to have the rock pushing in on the carabiner gate.

[Eric Wright]

Thanks, that helps.

I agree with you I'd use the BMS method and it is what we use with our U frame racks (no hyper bar). We don't tie off to the rope above the rack, I say it's overkill unless you were particularly nervy or going to be stopped for a long time or doing acrobatics that may accidentally release the lock.

I was talking about this with my girlfriend the other day and she asked why I'd need to have my hands free while rappelling. Before I could answer, she suggested a shadow-puppet show. Probably a good time for tying off above the rack.

I notice in your last photo the gate of your attachment carabiner is facing away from you, my preference is to have it facing you this way it is easy to see if it comes undone. It also means difficult lips etc aren't going to have the rock pushing in on the carabiner gate.

Whoops... good eye. I was paying more attention the camera tonight, I think.

[Scott McCrea]

Very nice post, Eric!

I usually use the BMS soft lock-off (LO) but add a twist or two before hooking the bite over the hyperbar. This is (or was) an acceptable LO at NCRC training.

I don't like running the bite thru the biner on a U-shaped rack because it doesn't help squeeze the bars together as much. The goal of locking off is to squeeze the bars together so tight, creating so much friction, the rope won't slide thru. The extra wraps, hooking bites and tying in above is make sure the bars don't come un-squeezed. The more secure this step is, the harder the LO.