In citing some apparent history for the Poldo tackle --which
has sort of similarity in being a supposed mechanical-advantage
structure w/self-locking ability–, an Italian knots book I think
touches a time prior to Ashley, but that structure also isn’t in
ABOK.
How do you find this structure helpful? I have a more
ambivalent view of it : it’s at times convenient, but is often
a PITA to implement, and often there are simpler options.
Let me ask you this, what would the strength of this knot be? after all, it is self locking, would adding a hitch make the strength better?
Well, that depends on how you implement the structure
(not “knot”, but a “knotted structure” --eye knots can be whatever).
In most materials, the locking will likely endure through rupture;
perhaps in the slippery HMPE and some other high-modulus cordage
there will be slippage such that adding a hitch would be necessary
to take the structure through rupture. In the canonical form of a
closed round sling with eyeknots & the wraps on one side, figure
that with most normally frictive circumstances (i.e., of what this
structure surrounds) one should get a higher tension on the
knotted side, but as push goes to shove in a break test there’d
also be greater mechanical stretch --i.e., knot compression–
on this side and tension would tend to equalize and maybe tilt
in favor of more on the unknotted side, leading to a break at
double the strength of the eyeknots, or more (as the unknotted
side might hold greater force via friction at the endpoints).