1accbjnb
https://imgur.com/a/eVf4T2oDoes this have a name, yet? I'd call it the wrapped collar lock, maybe?
I'm really liking it in the double bowline, 2accbjnb. It looks very easy to partner check, as well as all the usual, circumferential load, stable, secure without a backup knot.
Have the collar make an extra turn around the S-Part. Working end goes back up through that loop from the back side and comes back down through the nipping loops.
Six hard bends, back and forth, of the two nipping loops and the two collars, seems to work it loose after heavy loading.
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I experimented with having the wrap of the collar run under itself, instead of over. It tightens both wraps of the collar with one less tug of the working end, but it also loosens a lot easier.
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...experimenting with the girth hitch forms of nipping loops, as always, and with collaring the eye-legs...
When forming the nipping loops as done in the mirrored bowline, 12acbha, Girth hitch, closest loop loaded first (so they tend to pull apart), and with the switchback facing you, and making this lock in left hand (cowboy) form bowline, you form 12addbjnb. The primary nipping loop circles 4 lines, one of the 4 being itself before it forms the switchback of the girth hitch. This is the first knot that I have found where the switchback is absolutely unloaded. Judging by the tension on the knot parts, the primary turn of the collar seems to be absorbing some of this force upon loading, via the returning eye-leg (of course!). The cowboy girth hitch version of this lock pinches the nipping loop between [itself] and the [returning eye-leg to primary collar], preventing loading of what should be the break point bend of a girth hitch bowline. This knot stays in place well, but releases easily.
The cowboy (left hand) version of this knot locks the ongoing eye-leg extremely hard in both single and double versions of a bowline. The girth hitch adds nothing to this outside tail bowline knot. The switchback of a girth hitch gets in the way of the lock if pointed away. If pointed toward you, it adds unneeded complexity and does absorb some of the force while bending around one rope width.
Collaring the ongoing eye-leg (accidentally?) instead of the S-Part results in a stable and secure knot, when using either girth hitch or reverse girth hitch with the switchback pointed toward you. This is not surprising, as circumferential loading is not an issue and this move simply switches the positions of the S-Part and the ongoing eye-leg in the knot structure. This structure is bulky but remains very compact against the harness loops. It adds 1.5 inches. This is tiny, compared to a retraced 8 and most other knots, though this knot takes up much more vertical area. The tail and the switchback form backup collars, though they remain unused as the S-Part pulls in a direct line to the harness loops.