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Compact Bulldog Bone

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Rich Rule


It is an exciting time for tree climbers.  Equipment and techniques are developing to not only promote safe working practices but to allow you to work smarter and not harder.  The working life expectancy of a climber can be prolonged with hopefully less wear and tear being picked up on the way.


One such development in Arb climbing is the use of SRT climbing systems.  SRT has been used for a number of years for canopy access, borrowing ideas and kit from rock climbing, caving etc. Traditional ascenders have always been great a capturing progress but have lacked the ability to descend should the need arise.


In the last few years people have gone out on a limb like Morgan Thompson with his Unicender, Kevin Bingham with the Rope Wrench and then the Rope Runner, to develop tools that capture ascent but can be used to descend aswell.  


Another such pioneer in SRT Work positioning is Gordon Svedberg AKA Surveyor on forums such as The Buzz, Treehouse and Arbtalk.  After producing hybrid devices such as the OAR, Gordon came up with the idea of the Compact Bulldog Bone.


Having had the idea and developed prototypes, Gordon put out his design to a number of local arbs for testing and feedback via the Treebuzz internet forum in August 2014.  This not only proved to be a great method of getting the Bone out there, but provided a valuable source of information and feedback from the users to the developer.  Gordon took on board the feedback and over the next few months tried to incorporate the likes and dislikes he had received by tweaking the design of the Bone to allow for different users desires and rope types.  The main aims being to develop one device to allow the climber to seemlessly ascend and descend and be mid-line attachable with no droppable parts.  The Bone goes on the rope in seconds and can be removed in the same time frame.     The Bone is made of simple parts that are easy to replace.


The result of this is a Mechanical Ascender/descender, that is easy to modify and tune to your exact requirements.  Although being mechanical, it operates with a very hitch like feel.


For more information on the development process and the history of the device, pull up a chair, grab and drink and a 'sammich' and log onto


Gordon ships the BDB after having received a signed disclaimer and payment for the product and postage.  The BDB ships with instructions and 3 different sized bollards to be used on the top arm to control friction for ropes of different diameter.


I received my BDB in January after reading the hype on various internet forums.  I was not disappointed.  First impression were of a solid, robust (read bombproof) piece of kit that I couldn't wait to use.  After reading about the various modifications and development I already felt like I knew exactly how it would respond.  After a couple of goes low and slow, I tried the BDB on my favourite rope, Cougar Blue with the 5/8th bollard.  It responded very much like a hitch but I felt it needed a bit of time to bed in, or I needed to get used to it at least.  The first 4 or 5 climbs I had on the BDB were in the rain, I was crying for a dry day.  Even in the rain, once the ascent was dialled in with a HAAS and pantin, the BDB ate the rope for lunch.  Desending was a bit of an on off affair till you get used to it.  


After a particular wet day, working over a goose enclosure my rope needed a wash...  WOW!  What a difference that made.  The BDB literally tends slack so easily you can clip into a neck tether or chest harness and freeclimb the tree and it takes it all in with minimum sitback.  My BDB self tends with approx 20 foot of line below me.  Same deal with spikes, either spike the tree and it will tend depending on the rope angle or clip into a pantin or spikecender and up you go.


The more I have used this device the more I am growing to love it.  There has been some initial wear on the spine as the ropes and device get to know each other, but nothing to worry about at this stage.  One of the main selling points of this device is how easy it is to set it on the rope.  Everything is connected so there is no worry of dropping any parts.  It is a case of threading the rope into the arms, bending the rope and sliding a link over the rope and locking clasp.  This is just as easy to remove, just in reverse, making change overs or redirects less of a challenge and reducing the risk of getting your climbing device jammed in a fork.  As mentioned, there are various modifications  you can do to personalise your Bone.  The only thing I have done is adjust the tending point from the spine to the top arm.  In doing so, the top arm releases allowing the rope to flow even smoother through it without compromising safety.


There are a few vids and reviews of the BDB on youtube. 


For more information on the Compact Bulldog Bone, please read the Arbtalk thread posted above.  If you want to contact Gordon directly to order or simply query his design then his email is [email protected]  


Richard Rule

Freelance Climber

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Thanks Rich.   There are indeed many videos now on youtube, maybe search there with the words "compact Bulldog Bone".

I would add that I now make the Bone with an adjustable bollard, which is moved with a stainless steel captive machine screw, very much like the chain on a chainsaw is adjusted, tighter or looser.

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I still use it.  The spine does wear in to a rope.  I tend to use it when I do spruce and pine and sappy trees out here.  Mainly because it responds best to tachyon due to the wear on the spine.  The tachyons gets used as it is an old rope which I don't mind getting crapped up.


I have a couple of Rope runners as well which I rend to use on the bigger climbs requiring a longer rope.  


But whenever I use the BDB again, I realise how good a piece of kit it it.

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