Compact Bulldog Bone multicender
It's a dirty job but someone has to tempt you with gear reports!
Many years back I received a prototype device from a North Carolina inventor known as Surveyor. It was designed as a mechanical hitch replacement for DRT climbing. It was built from hand-worked chunks of aluminum, what appeared to be motorcycle chain links and a few steel bolts. It worked well but it was big and heavy. I returned it with comments. Since then Gordon (Surveyor) has been working away, persistently refining and improving his devices. Gordon played a part in the development of the ZK-2 Rope Wrench, the wrench's inventor Kevin Bingham integrated some of Gordon's ideas into the ZK-2. This is the nature of the collaborative tree gear inventor community. I think it's the reason why people like Kevin, Gordon, Paul Cox (Hitchhiker) and now Jaime Merritt (Akimbo) are innovating ahead ahead of the established tree gear development companies. They don't operate in a black box, they send prototypes out into the climbing community for testing and feedback, and they implement the feedback into their devices as they evolve them.
Eventually Gordon started designing an SRT multicender. Multicender meaning it goes up or down without a switchover. In late 2014 he introduced a prototype Compact Bulldog Bone. The previous version of the BDB (Bulldog Bone) wasn't so compact. Now in 2017 the compact BDB is quite refined, still technically a prototype but very nicely designed and built. I had a chance to try it at a recent winter rec climb. I really liked it, especially because it runs well on my Tachyon ropes. A big positive for the BDB is that it can be quickly placed on the rope, or taken off the rope midline while still attached to the climbing harness. The widely awaited Akimbo has that feature but it may not come to market for at least another year. Likewise the Rope Runner 2 coming out who knows when includes quick on/off the rope features. The original Rope Runner is excellent but a pain to remove or place on the rope midline. The Akimbo has two adjustments where it contacts the rope so it will be ultimately flexible for different rope types and climber weight. The Rope Runner has adjustment range on the top rope contact point (the bird), works great on Yale 11.7 mm double braids (Poison Ivy etc.) but I could never get it to work on my favorite rope Tachyon.
I finally pulled the trigger and ordered the BDB form Gordon. It currently comes in two variations. One has an adjustable top bollard (adjustable bird), the other comes with three different size bollards that can be installed on the bird. I opted for the 3 bollard option, a little less money and reasonably flexible for different ropes. I've done a couple climbs on it. Every one of these multicenders has its quirks but once you get used to operating them it's all good. Same is true for the BDB. I tested it in SRT and DRT modes on Tachyon with the medium size bollard installed and it works very well.
Compact Bulldog Bone SRT mode
Gordon recommends a corner trap to keep the carabiner from rotating and crossing the gate. I used a short piece of slingshot tubing. The carabiner never needs to come off the device so a semi-permanent corner trap works well.
I made my own connection point for my HUT. The HUT is some type of bungee tether or other configuration that advances the device hands-free as you ascend. On ascent the rope drops freely through the BDB, better than the ZK-2 Rope Wrench and a little better than the Rope Runner. Mileage varies per rope type and where you attach your HUT per device.
Here it is in DRT mode, not the most streamlined but it works well. I frequently switch between SRT and DRT when I'm climbing conifers so this is a strong feature for me.