BOB tethers and tie-ins
Rappel extension and tether
You probably already know a few options for tethers. While I also employ the use of of a basketed sling with an overhand (sometimes offset), the BOB is my typical rappel extension. This mostly stems from my particular circumstances. I’m often guiding or climbing with less experienced partners. With that, I’m usually pre-rigging rappels and going down first. The BOB allows me to have a long tether, enabling me to position myself below other members of my party and set up my rappel device lowest on the ropes. Additionally, this style of tether has the benefit of being easy to untie when it is no longer needed.
I see two possible downsides for a BOB tether: the length can often be too much and it can be challenging to tie. If the length is a problem for me, I’ll add a clove hitch on the end of the tether. This allows for adjustment of the length, though not as easy as a dedicated PAS. When it comes to tying this BOB, we cannot use the overhand and flip method. Instead we have to tie the bowline in a more traditional manner. Start by passing the working end through your belay loop (tie-in points are also acceptable), then create a full turn in the standing end. Act like you’ll be tying a bowline with a bight, but instead of wrapping around the standing end, pass the standing end through the bight of the working end. To tighten, pull on the standing end and part of the eye leading to what was the working end. If you got it wrong, the knot will either dissolve or collapse.
For more information, including pictures showing how to tie the BOB tether, check out this post by John at Alpine Savvy.
*Additionally, Jono Lewis recently shared another use of the BOB with me. He uses it to shorten alpine draws. Instead of a creating a pseudo-termination with an overhand knot, Jono ties a BOB and adjusts the size of the eye strands to achieve his ideal length. This method would not work with a simple overhand on a bight, since changing the size of the bight doesn’t change the overall reach of the sling. Now the sling is being used end-to-end with an appropriate application of a knot, instead of in a way with potential for the knot to roll, shift, or fail.
Connection for lowering
This use is fairly simple. Instead of tying an overhand or figure-8 and clipping to your belay loop when lowering off a single-pitch climb, use a BOB. It takes marginally longer, but you won’t have to fight to untie it when your arms are still pumped.
Fixing lines
The BOB is by far my favorite knot for fixing lines while aid climbing. Way better than a clove hitch or alpine butterfly in my opinion, since it’s faster to both tie and untie. If you ever fix lines with the BOB without being tied into the end, I highly suggest tying a stopper knot in the end to prevent rapping off the wrong side accidently.
Tying into the middle of a rope
I originally saw this from AMGA Rock Guide Andrew Megas-Russell (@megas_sends). Here’s a video of him demonstrating the process.
The BOB cannot handle loads when the standing ends are pulled away from one another (biaxially loading). This makes it a poor choice for end-roping (two climbers being belayed simultaneously on the same rope over easy terrain) or glacial travel. However, it is stable when both standing ends are loaded in parallel or only one strand is loaded. With this in mind, we can use a BOB as a way to connect mid-line without the use of a carabiner in certain situations found in 5th class rock climbing.
A party of three climbing in parallel with one rope could have one member tie in with a BOB while the others are on the ends of the rope. With two distinct ropes, the leader is able to unclip, or perhaps untie, one of the ropes to address any crosses or twists. Since the leader is unable to free an end of the rope when using a BOB, the party must be extremely mindful about preventing twists. Therefore, I only recommend this method of tying in for folks extremely familiar with climbing in parallel. While it is possible to use a BOB for a party of three climbing in series (aka caterpillar), I don’t believe it’s the best option. Since you cannot biaxially load the BOB, you eliminate the possibility of providing the middle climber a back belay over traversing terrain (having a belay from both anchors, mitigating the consequences of a swing). If the route has no traversing sections, then perhaps a BOB could work for a party climbing in series. Another drawback of using a BOB in a party of three is that the order of the climbers in relation to each other must stay the same. For example, for a party of three with climber A tied into one end, climber B in the middle, and climber C at the other end, the only possible orders to climb are A->B->C (series), C->B->A (series), or B->A||C (parallel).
You could do the same with a party of two utilizing a singular half or twin rope: one member ties into the middle with a BOB while the other has both ends. In this case, I highly suggest using the ropes as twins since both lines will be identical, thus making it challenging to selectively clip as needed in a half-rope system.
Why tie in this way? Well, for starters it’s less bulky than other options. I used to tie in midway using a retraced overhand on a bight, then clipping the bight back to my upper tie-in point. If we were in series, I would have someone clip into an alpine butterfly using two opposite and opposed lockers. Both of these options have quite a lot going on, making it more challenging to utilize the belay loop for other functions, like belaying. A BOB also doesn’t use any additional material. Extra carabiners aren’t needed. Finally, a BOB is much more secure than anything using carabiners. There’s zero possibility of cross loading, unclipping, or having gates come unlocked.
The catch comes from how the BOB is tied and untied. Start by passing a bight through your tie in points, making it quite long. Form a loop to create the nipping loop of the bowline and pass the bight through it, similar to how you would create a tether. Step through the bight (yes, put it over your head), then snug everything down compactly near your belay loop. See how this is a pain to get on and off? I would suggest only using the mid-point tie-in BOB when you can securely be unattached from the cliff at the top of the climb (e.g. a walk off). While it is possible to remove while tethered in, your rope management skills will certainly be put to the test during the process.
*Edited September 17, 2024
