Don;t mean to pester you, can you qualify the 5-8% difference... any references ??? I recall hearing bowline was smewhere around 60% strength and double bowline is around 75-80%...
when you add the friction of the rope on the piece it acts like a multiplier, making the difference even more consequential in terms of total force needed to break the rope.. I may not have said that just rigt, but you get my meaning ...
Daniel you stated that the regular bowline broke and the double did not. I'm not doubting the double being slightly stronger, but could it also have been that the regular bowline was tied at the end of the rope where the most wear would be present. I'm not doubting you but maybe the original knot was tied in a "bad" section of the rope.
so long ago I couldn't say for sure....... this conversation has made me re-think the way ropes and knots are tested.. seems like tying arigging rope to a piece of wood and then pull testing would give the most accurate information.
That was one of my first thoughts..
Previously, i honestly tried to track down some of the numbers i've watched over years and couldn't find any;
many broken links in my stash etc.
i do know that i really pushed for DBY over years; and fought this narrower difference stated between the 2 for years;
to some pretty smart peoples on IGKT etc.
Consistently, the wisest always said many of the ratings are parroted, some made up, most tests not scientific enough to stand scrutiny etc. etc.
For years i chased and compared all i could find.
Also, there is so much if dressed and set properly, different materials/braids/stiffnesses that affect these knots in families when looking at tables of them that it is hard to make generalizations. Sometimes same tester finds this group of knots stronger in his dynamic lines but other group stronger in static lines etc. Then fishing lines totally different, then dyneema etc. (just to show range, but lessons at each layer too)
Over time; fighting for DBY, holding it in my hand, looking at the architecture and how all rest of my theories and understandings lead towards:
Eye is dual legs of pull equal to single leg of Standing Part as most loaded single leg.
Weakness from deflection from pure inline, at most loaded part >> just outside knot/ where they break!
That isn't much different at that point in either single or double Bowline;
They both start loaded same and deform from pure inline same.
Main difference at that point of the architecture is on single immediately deforms again, double rides out more before makes same change.
All the rest of my model theories actually more in line with what they were telling me about Double Bowline!
So i had to fall back!
i'm still all for DBY anyway, but that is where i've chased this to; and that was the range that stuck in my mind.
Interesting, and good to know. Adding the double takes like literally two seconds.
“Experience is a hard teacher because she gives the test first, the lesson afterward.”
Good stuff. I see that Sampson seems to be involved with these kind of test often. I'll look into this a bit deeper tomorrow. Thank you for posting
Got it double blowline= two rabbit holes