Compact Bulldog Bone

The Bulldog Bone has had some testing undertaken by a third party, and this is the results I have received. There is some confusion about item 6, as I understand it the rope did not actually escape the Bone with the swivel link left open, but there was distortion to the linkage which caused the rope to be pushed sideways into the "notch" or gate opening.

Compact Bulldog Bone with 1-3/8" pivot length testing results by independent third party. (all tests with vertical loads):

1. 5/8" bollard with Tachyon Pink, 400lbs. first slippage motion, 731lbs. consistent slippage.

2. 3/4" bollard with Tachyon Pink, 366lbs. first slippage motion, 549 lbs consistent slippage, 610lbs. jumped 6-7".

3. no bollard with Vortex Cool, 671lbs. first slippage.

4. 5/8" bollard with KM III (7/16"), 305lbs. consistent slippage.

5. 3/4" bollard with KM III (7/16") 305lbs. consistent slippage.

6.5/8" bollard with Tachyon Pink, both side snap links left open, 244lbs. and rope slipped away from device at bottom friction pin out gate opening.

7. 3/4" bollard with Tachyon Pink, both side snap links left open, 366lbs. consistent slippage, device became distorted enough to not allow gates to close or open easily if not at all.
 
surveyor said:
The Bulldog Bone has had some testing undertaken by a third party, and this is the results I have received. There is some confusion about item 6, as I understand it the rope did not actually escape the Bone with the swivel link left open, but there was distortion to the linkage which caused the rope to be pushed sideways into the "notch" or gate opening.

Compact Bulldog Bone with 1-3/8" pivot length testing results by independent third party. (all tests with vertical loads):

1. 5/8" bollard with Tachyon Pink, 400lbs. first slippage motion, 731lbs. consistent slippage.

2. 3/4" bollard with Tachyon Pink, 366lbs. first slippage motion, 549 lbs consistent slippage, 610lbs. jumped 6-7".

3. no bollard with Vortex Cool, 671lbs. first slippage.

4. 5/8" bollard with KM III (7/16"), 305lbs. consistent slippage.

5. 3/4" bollard with KM III (7/16") 305lbs. consistent slippage.

6.5/8" bollard with Tachyon Pink, both side snap links left open, 244lbs. and rope slipped away from device at bottom friction pin out gate opening.

7. 3/4" bollard with Tachyon Pink, both side snap links left open, 366lbs. consistent slippage, device became distorted enough to not allow gates to close or open easily if not at all.
Click to expand...
That is some information there. What's the interpretation of these findings doctor?
 
It seems with some ropes it actually grips better with the 5/8" bollard rather than the 3/4". The swivel snap links need to be closed for safe operation, as otherwise they will yield, but not fail. The Bone will allow consistent slippage in the 1.35-3.25 Kn range depending on the rope.
 
I installed the 3/4" bollard and tried it on 11 mm HTP. At 165 lbs, it held me stationary with no problem, but as soon as I started a descent, I couldn't get it to stop. I thought that was interesting, since with the smaller 5/8" bollard, it frequently slipped but was a more gentle slide down the rope that could be easily stopped.
 
All very interesting and provides empirical confirmation of my subjective experience with bollard sizes.

Also, isn't it fair to say that slippage at those weights is not necessarily bad aND may be good in that it suggests a shock absorbing capacity: as I don't weigh 400 lbs?
 
I have just received the Samson Vortex 'Hot' and about to try it on the bone I have that didn't perform well despite having tried any combination of bollard with the Cougar Blue recently...I have a fear that this time I got the one working well...I 'll keep you posted...As a reminder I have a 13mm that works super with the bone but cannot be spliced and it glaces up becoming hard on knots and very tough.
Let's see...
 
Tico said:
I have just received the Samson Vortex 'Hot' and about to try it on the bone I have that didn't perform well despite having tried any combination of bollard with the Cougar Blue recently...I have a fear that this time I got the one working well...I 'll keep you posted...As a reminder I have a 13mm that works super with the bone but cannot be spliced and it glaces up becoming hard on knots and very tough.
Let's see...
Click to expand...
Hhhmmmm,hhmmmm, amazingly my Petzl Grip 13mm......wins the competition!!!
I have a Vortex 40 meters rope with a tight splice and another one which is 15 meters which I tried my experiments with.
1) With the small bollard: just about like the Cougar blue, no creeping but falling with no control.
2) Medium bollard: almost the same
3) Big bollard: you really need to control it grabbing firmly with the other hand on the slack of the rope and it doesn't go smooth at all always having the bone running down too fast.
Not satisfied, unless I go for another 13mm.
The Vortex is a very nice and static rope but for my bone it doesn't give that quality descend I get with my rigging/rescue rope that I'm reconsidering being a very good one at least for the bone.
I wouldn't mind giving away the 40 meters Vortex and keeping the 15 meters that I can also use with the other devises I collected before purchasing the bone. I think it has to do with the supple characteristics of the rope which could be good with other bones...not mine! Just to make this point a bit clearer, with the Petzl grip I cannot even think of putting the medium or the larger bollard...it will get stucked. With the Vortex it runs down too quickly in a scary fashion with little control and even with the 3/4 bollard!!! I wasn't expecting this outcome!
 
Tico said:
.... which could be good with other bones...not mine!....
Click to expand...

What do you think is different about your BDB compared to others?

I'm beginning to wonder if you have a heavy on/off touch or if you just like a very slow ride down....or both.:D
 
Wondering that myself. I run both colors of Vortex with my BDBs. Now mine do have 1" (25.4mm) centers but I run the 5/8 bollard and have finger tip control and little to no creep.
 
gmcttr said:
What do you think is different about your BDB compared to others?

I'm beginning to wonder if you have a heavy on/off touch or if you just like a very slow ride down....or both.:D
Click to expand...
I like a very controlled and steady descent without falling dead if I release down the upper arms a little more...I've been quite busy these days but planning to post a video showing the difference between the two ropes and also the way the bone behaves on them also switching bollards and everything.
Not to mention that also with the zigzag I have the same outcome: the 12.7 Vortex seems too skinny and releases too quick as soon as you touch it...I still don't understand how can people use these devices with thinner ropes...Is it me? When using a rope friction hitch this doesn't happen! I think I'm stuck with 13mm. ropes built for rescue and such!!! Someone please help on this one!
 
Tico said:
I like a very controlled and steady descent without falling dead if I release down the upper arms a little more...I've been quite busy these days but planning to post a video showing the difference between the two ropes and also the way the bone behaves on them also switching bollards and everything.
Not to mention that also with the zigzag I have the same outcome: the 12.7 Vortex seems too skinny and releases too quick as soon as you touch it...I still don't understand how can people use these devices with thinner ropes...Is it me? When using a rope friction hitch this doesn't happen! I think I'm stuck with 13mm. ropes built for rescue and such!!! Someone please help on this one!
Click to expand...
When you operate any mechanical hitch, does your hand have a reference point? Say your fingertips are on the actuator, is your palm against anything? I find that without a reference point, you can easily get that all or nothing feel.
 
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