I have a lot of experience with the Faders Sum. When Faders was testing the Sum, I was lucky enough to be invited into the preproduction test group.
I'd like to point out a few things about the device.
First off,
the breaking direction is down not up! Pulling the rope up produces a wide bottom U on the rope. Because the bottom is so wide there is very little friction/leverage produced by the device. Pulling the rope down produces a backwards N shape in the rope. This will arrest a climber whether the cam engages or is held open.
Let's talk about the mechanics of lowering with the device. With your break on (remember hand in down position), you can disengage the cam. Rope will still not pass through the device because of your break. In order to allow rope to pass through the device, you will have to push the device perpendicular to your body (
while retaining your break!).
When pushed down, the snape of the rope changes from a backwards N to a lightning bolt shape \/\ then into a L, shape. If you push the device below your waist it forms a ! shape straight pass. Note, each of these shapes of the rope have less friction/leverage than the last.
Mechanically, the Sum functions exactly like an ATC when it is not held below the belay loop, it forms a backwards N or S bend in the rope.
If you ever grip the device below your belay loop, you are holding the cam open.
As with all camming belay devices, you need a way to safely feed out slack. For the Sum, you can do this as fast and safely as you can with an 8.
Step 1. Keep your break hand on at all times!
Step 2. Do not hold open the cam (i.e., keep the device perpendicular to your body)
Step 3. Pull slack toward your chest.
If you need to pull a lot of slack out quickly, you may:
Option 1. Lightly grip the Sum between the pinky and palm of your break hand.
Option 2. If you have small hands, you may also use your ring finger.
However, if you use either of these options do not skip Steps 1, 2 or 3. If the climber falls while your pulling slack, the device will be pulled upward, your break will be on the rope, the backward N shape will form in the rope and you will catch the climber.
The Sum provides the speedy rope delivery of an 8 with much easier breaking.
steep4me wrote:Man, these things really freak me out. My list of partners is narrowing each season. No SUMs and no. Cinches. Every single incident involving a gri gri or ATC had to do with pilot error. If there is ANY chance that a competent belayer could have their hand on the brake and deck me anyway....I'm not willing to take that risk.
Next time I see you at Stone Summit, I'll personally demonstrate to you the safety of the Sum belay device. Rachel & I are both well aware of safety issues involved in climbing equipment and usage. Neither of us will allow anyone to belay us that we've not tested first.
Thanks everyone.
P.S. - a fun aside —>
http://vimeo.com/4148256