RRC Archives

pigsteak wrote:
steph I am clearly out of my league as I have never used the SUM but I am interested in what happened... in the vid it merely sounds like dirt or sand is stopping it from moving when Todd has his death grip on it...is that correct, ie it might need to be cleaned?

Actually, he didn't have a death grip on it and when I held it (lightly), I couldn't lift the lever at all. However, this may not matter at all. At this point, we're speculating the possibilities because everything seems as though it were in place to work (carabiner, rope size, rubber stopper, and brake hand on rope).

More to come later when more is known. I've been in touch with Rick Weber who we know does test gear and I've learned more about his involvement with that. He has the equipment to do it so the ball is rolling ...

But, we may learn nothing that states what happened in that moment.

Meadows wrote:You can insert any device into that statement and still get a yes. I've seen the ATC misused and I know of two instances where the belayer lost control on a fall.

It is more difficult to misuse an ATC. You can't be arguing for equivalence between any and all manufactured belay devices and their related protocols. That is a blatant abdication of one's freedom to analyze and think. Because you have seen people misuse the ATC does not mean that the simple mode of the ATC does not lend itself to the safety of the protocol.

How are you supposed belay with the sum... brake hand on the rope or on the Sum?


How are you supposed to feed slack with the sum... brake hand on the rope or on the Sum?


When the cam is held down on the Sum and slack is rapidly being pulled through it (as in a fall situation) does letting go of the Sum allow the cam to engage (as it would with a gri gri)?

climb2core wrote:How are you supposed belay with the sum... brake hand on the rope or on the Sum?

Break hand on the rope always... like any other device.

climb2core wrote:How are you supposed to feed slack with the sum... brake hand on the rope or on the Sum?

Both. 3 fingers and thumb around the rope, and the SUM between your pinkie and resting in your palm. Simply pull the rope towards you and it easily feeds slack.

climb2core wrote:When the cam is held down on the Sum and slack is rapidly being pulled through it (as in a fall situation) does letting go of the Sum allow the cam to engage (as it would with a gri gri)?

Absolutely. But you should still always keep a hand on the brake end of the rope.

Seems ridiculous to design a device that doesn't put a more serious bend in the rope. A brake hand on the rope won't do much for such a small increase in friction due to the device, especially for someone expecting a locking-assisted arrest.

cliftongifford wrote:

climb2core wrote:How are you supposed belay with the sum... brake hand on the rope or on the Sum?

Break hand on the rope always... like any other device.

climb2core wrote:How are you supposed to feed slack with the sum... brake hand on the rope or on the Sum?

Both. 3 fingers and thumb around the rope, and the SUM between your pinkie and resting in your palm. Simply pull the rope towards you and it easily feeds slack.

climb2core wrote:When the cam is held down on the Sum and slack is rapidly being pulled through it (as in a fall situation) does letting go of the Sum allow the cam to engage (as it would with a gri gri)?

Absolutely. But you should still always keep a hand on the brake end of the rope.

So, based upon this information the following should be true:

1.) Regular falls should be a non issue as the brake hand is on the rope.
2.) Falls occurring while feed slack should still be catch-able as the brake hand remains on the rope.
3.) Letting go of the Sum in the event of a fall should arrest the fall.

So unless the Sum in question was defective and letting go of the Sum DID NOT engage the cam, it would be belayer error. In the event the cam did not engage in the fall, then it becomes a questionable call as the brake hand should still be on the rope... the question in this scenario is:

Is there enough friction using a SUM as an ATC to arrest a fall with the cam dis-engaged?

Spikeddem wrote:Seems ridiculous to design a device that doesn't put a more serious bend in the rope. A brake hand on the rope won't do much for such a small increase in friction due to the device, especially for someone expecting a locking-assisted arrest.

Agreed... the sum seems to rely very heavily on its technology, ie. the flawed notion that it's going to work every time. In the event of a cam failure, I bet you would get as much friction just running the rope through a friggin' carabiner and braking upwards! No thanks, a hip belay would be safer than that.

This is exactly what I'm thinking, too....

If your brake hand is on the rope but the device STILL can potentially fail...... then that device is absolutely a deathtrap, Right??? That's worse than having a gri gri loaded backwards!

cliftongifford wrote:

kurtnorv wrote:When I used to work in a gym we would practice catching a climber, who had a back up belay on another rope, with a grigri with a piece of tape over the caming device so it would fail. To show that a grigri will work the same as an ACT if the belayers hand was on the brake side of the rope.
Would this be possble to catch a falling climb with a SUM that had the camming device taped so it would stay open?
What if you didnt know the assisted camming was not gonna work would you be able to catch the falling climber?

Yes, when my first SUM wore out and quit working/camming... It caught a lead fall just fine, I simply caught the climber and lowered like you would with a munter, without having to engage the cam to make it slip. The device was shot, but still worked when used properly, with a brake hand on the rope not the device.

There is either more to this story or I'm declaring shenanigans. I'm having a hard time believing that the device totally failed to brake assist and you casually locked off a lead fall and lowered the climber.

We all say that we're as vigilant on the gri-gri brake hand as with an ATC, but really, the reality is we're likely not. Brake hand is on, yes my hand is on at all times, but I know that for me, if the brake totally failed I would be caught very much by surprise and may be able to hang on or maybe not. I always freeze when I catch someone with a gri-gri and take a look at my body and hand position, just to make sure that I'm still instictive enough to lock off the brake hand and be in the right position, in the event the device failed. But if it did, I would probably crap my pants and would not be surprised if my brake reaction wasn't late / sloppy.

Caribe -

Yes, actually it does. Let's test this out this weekend. How about you take the whip from the tuna town anchors while I belay you on an ATC?

Everyone -

Human error is not ruled out.