Compact Bulldog Bone

Is there any way to install a pulley under a BDB that improves it for 2:1 setups with hand ascender and pulley? I recently tried the zig zag with Chicane and it seemed better at that, perhaps due to the pulley on the bottom of the ZZ. I dont like how hard the chicane is to loosen on limb walks though when I'm not leaning my whole body weight into it. In that respect my BDB is definitely superior and probably still my SRT device of choice. One guy on FB said putting a pinto pulley with it made it worse not better, not entirely sure why but I'll take his word for it since I don't have a pinto pulley. any other methods anyone has tried to improve slack tending/2:1s? Don't suppose you could build a pulley into the bottom of the next BDB version?
 
I tried a pulley under my BDB also and, yes, it makes things worse not better. That is the one weakness of the BDB in my opinion, that it lacks a pulley to smoothly fairlead the rope back up the way one can do MA with a Zigzag.
 
I tried a Pinto on the teardrop of the BDB but it messes with the geometry of the thing. Just doesn't line up right. I think the pulley would have to be permanent on the lower arm somehow, same as the ZZ. The BDB is great at what it does, however; and of course the ZZ is not midline attachable like the BDB. Each has its place I guess.
 
Mike M said:
Is there any way to install a pulley under a BDB that improves it for 2:1 setups with hand ascender and pulley? I recently tried the zig zag with Chicane and it seemed better at that, perhaps due to the pulley on the bottom of the ZZ. I dont like how hard the chicane is to loosen on limb walks though when I'm not leaning my whole body weight into it. In that respect my BDB is definitely superior and probably still my SRT device of choice. One guy on FB said putting a pinto pulley with it made it worse not better, not entirely sure why but I'll take his word for it since I don't have a pinto pulley. any other methods anyone has tried to improve slack tending/2:1s? Don't suppose you could build a pulley into the bottom of the next BDB version?
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I have no experience with the BDB but just a thought on this, since the pulley seems to complicate things, how about running the tail of your rope through the hand ascender and pulley. With the end terminated back to you it will give you a 2:1 then tend your BDB as normal for progress capture on the SRT line. Of course you could add a hitch to your tail as well if you dont want to work two ropes as once.
 
Yes, the Bulldog Bone works fine as 2(3?):1 for me. Just as Jehinten describes, The Bone tends best by allowing the whole bone to tip as it swivels at the attach point. This allows the bottom arm not to pinch on the spine. I think this is the reason a pulley below does not work well, as it causes the bottom arm to swing up against the spine.
 
Do you think something that pushed up on the spine and not the lower arms when the rope is hand tended would help?
 
Yes, if the spine is pushed up, then the arms swing down. But in fact if the rope is the right size, as you hand tend the Bone, much like a hitch climber, the Bone swivels over and forms a sort of virtual pulley on the two chain link pins.
 
If you lOok at the bend around the two pins and figure their friction in ,as smooth as they are, I feel its negligible. As if to compare an x ring to a block in how they "feel"..
 
Treetopflyer said:
If you lOok at the bend around the two pins and figure their friction in ,as smooth as they are, I feel its negligible. As if to compare an x ring to a block in how they "feel"..
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Yeah not sure if it's just the bend radius or friction or what or simply the nature of the zig zag to tend a bit more easily by pulling the tail upwards. I might borrow a pinto off a mate and try attaching a pulley to the opposite end of my karabiner, at the bridge end and see if it changes anything.
 
Seattle High Rise said:
I don’t know if my feedback helps you guys, primarily because I’m not familiar with the most popular tree climbing ropes. Personally, I think Gordon’s design is the best mechanical climbing/descender out there. The design allows the most braking leverage that you can easily release. I don’t mean any disrespect to other designs out there. There are certainly other elegant designs that folks seem to really like. I modified Gordon’s design to work at specific work load with a specific rope (km3). By the way, I highly recommend standard km3 over km3 max. They perform basically the same when dry. But, km3 max is terrible when it gets wet (jerky, not smooth). However, standard km3 stays smooth in the rain (even when fully saturated with water). I’ll post some photos to try and add visuals to some of my comments. I think all of Gordon’s designs are probably great. I’ve only tried the adjustable (which is terrific up to a certain load) & my modification with the long bollard. It all depends on the work load & which rope you use. My mod climbs the same. I don’t climb very often. But occasionally I install large banners. So, I’ve climbed a few times installing banners. Having a 4 way adjustable spine hasn’t been a problem. I’m currently working on my 4th adjustment of my first spine. The only negative of my mod, that I’ve found, is the extra weight, which isn’t really that significant. I’m using a stainless spine & bollard. Also, the design I use negates the “no spring” issue. If you put it on km3, unloaded, & shake the rope, it doesn’t fall down the rope. However, with my mod, I needed mylar washers on all the metal to metal contacts to make releasing the top arm perfect. Hope this helps.
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It looks like your spine is wearing off to the side. So far the all the BDBs that I have used had even wear in the center. I'm just wondering if it matters and why yours is like that?
 
Seattle, I believe your self modified lower arm attach point is somehow canted or slightly off center in order to create that sort of offset wear on your modified spine. Or perhaps because the Bone is not centered on your bosun chair spreader bar? That must create uneven wear on the arms also?
 
No, perhaps my previous photo was misleading. I’ll try and post a better one. Basically, because of my chair the rope is getting fed through my BDB at an angle. Whereas, if you’re in a tree harness the rope hangs pretty much directly below you & feeds straight in. Regardless, it’s inconsequential. It doesn’t create any real problems. I made enough spare parts to last the rest of my working career. I hope that explains it better. Thx
 

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Seattle High Rise said:
No, perhaps my previous photo was misleading. I’ll try and post a better one. Basically, because of my chair the rope is getting fed through my BDB at an angle. Whereas, if you’re in a tree harness the rope hangs pretty much directly below you & feeds straight in. Regardless, it’s inconsequential. It doesn’t create any real problems. I made enough spare parts to last the rest of my working career. I hope that explains it better. Thx
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Do you wash windows in Seattle do you know a Steve Layman? Lives on Whidby Island. Washes windows in seattle.
 
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So I climb srt probably 75% and will go doubled rope when it makes sense, both have their place. I've never liked using BDB much for double rope because of all of the flop and while there are some tricks to address the flop, the system becomes a hindrance in itself as you want to move your tie in.

Anyways, I always use my magnetic necklace to tend BDB when climbing SRT and while it was hanging on my harness the other day not being used during a doubled rope climb I had an idea...worked great for the one climb I used it on so far. When I changed tie ins, I just yank the magnets apart and then they find each other when you bring the anchored end back around. Could make something more purpose built but as I have the necklace on my harness already, I just coiled that around the anchor end and it stayed put, now it always has a job single or doubled....

Sorry, it was getting dark when I snapped the pictures...

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Magnetic Tending Necklace for SRT

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Up close


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DDRT magnetic tending!
 
Another option for automatic tending is to make the Bone able to extend away from the climber, who only needs to pull down on the climb line for it to advance. A single eye cord connected directly should be flexible enough to eliminate the swivel. If this cord is routed on top of the carabiner, the hitch can be tended one handed.
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