Running bowline on anchor sling

Muggs

Muggs

Been here much more than a while
Location
Canuckistan
In a situation where you need to anchor a portawrap with a dead eye sling, it has usually been shown in the past that the only valid options are a cow hitch or a timber hitch. Years ago I made a video showing how I set it up using a running bowline instead, but I got a lot of pushback. Lots of people online said it was inappropriate to use a running bow for this. I disagreed then, and I still do. Does anyone know why a running bowline is no good in this situation? Same question for a ring as a redirect.

Breaking load of hitches and ropes used in rigging
20230826_202100.jpg
 
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If that is a link in your post, I can't get it to work.
I would think for two reasons. 1) Harder to untie. 2) With this I may be wrong, but I suspect it to be true that the knot would weaken the system. Knots usually case the breaking strength to be reduced in a rope system, whereas a cow hitch or timber hitch does not weaken the system as much.
My 2 cents, for what it is worth.
ps: I have a 5/8th 200' hank of one time used Polydyne that has a bowline on a bite locked up right smack dab in the center that I have not been able to untie for about 2-1/2 years now, but I keep trying.
 
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If I'm not mistaken a figure eight knot retains the most strength among all of the knots/hitches (~80% if memory serves, compared to ~75% for the bowline) so why don't we use IT more often?
 
Thank you. I seem to have downloaded it four times now. LOL
Interesting results. I suppose the friction going around the log reduced the load on the knots, so the breaking occurred at the bend. That sort of killed my weakening argument with a knot. So, I guess I am only left with the untying aspect.
It would be faster to use a bowline to tie, but slower to untie, depending on the load put on the system. Six of one, half dozen of another.
 
@Chris Schultz
@Muggs
To be fair, I was pulling on the rope with a 25,000 lb winch that had to be near the breaking point of the rope with a knot. Ball park of 20K lbs. Not something most of you are going to be doing.
I have soaked it in soapy water, and have tried most of the other methods, including boiling it in lard. I don't recommend that one.
A couple of days ago I ordered a new 200' 5/8th Polydyne rope to replace it and will probably just cut the other one into two 100 footish pieces. It has got to be near toast anyway.
First knot I have never been able to undo. But then, first knot I tightened that much. It is a rock solid, and I have pretty much chewed up the cover in my attempts to loosen it up.
If I ever do that stunt again I will probably opt for a figure of nine or something with a bit more internal friction. The winch was attached to the bowline in the middle. We were able to untie the two ends from the load that also were bowlines, amazingly.
Lesson learned that night: When pulling an REA bucket truck out of a swamp... use their rope.
 
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When teaching rigging I always tell the trainees that my preferred method is always the cow hitch because it can handle multidirectional loading, easy to untie, and strong. The disadvantage is that it uses a lot of rope. My second choice is a timber hitch. It doesn’t use as much rope, is strong, but requires you to think about direction of loading. A running bowline is an acceptable option that uses even less rope than a timber hitch but will tend to move around more so care needs to be taken to make sure that this won’t cause issues during rigging operations. One way to limit this is to make the eye that goes around the hardware end of the sling as tight as possible or get creative with some prussik slings.
 
Muggs said:
Dave, I have used a stick in the bowline when anticipating a hard pull before. Helps to untie. A tapered marline spike would work even better.
View attachment 89817

For tying the running bow nice and tight to the trunk, I re-dress the knot like this:
Click to expand...
Yep, I have used that as well in the past. Actually have a piece of dowel rod in my gear bag for doing just that. But it just didn't occur to me at the time. Tired, wet, muddy, and wanted the drama to end so I could go home and shower and get some sleep. Coulda, shoulda.
 
I work with a guy that’s been doing the running bow since ‘72

Edit for clarity: I mean in the aforementioned configuration. He says that if you trust it to catch a log then what wouldn’t you trust it to do?
 
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