ABoK 1514
He called it a “Loop Lashing”, and categorized it as a bend.
This is interesting because most people think that the versatackle was invented in the mid 1980s.
Close, but not quite. Note that the top loop in the 1514 diagram is only run through one time, hence the need for a separate tie-off.
There are many different knots under this name. If we mean the rope-made block and tackle mechanism, able to deliver a mechanical advantage, where instead of pulleys we just cross the ropes and allow them to slide on each other, I believe that Archimedes knew the “Versatackle” ! The systems of pulleys belong to the so-called “simple machines” (1)
I think we can credit Ashley with being more than just close - the text for 1514 includes “…One or several turns are made through the two loops and they are tightened at every turn.” The fact that he goes on to say that the structure is finished with half hitches is something some users of the versatackle do anyway, needed or not (my italics in the quote).
Barry
OK, but I wonder if he actually used such a mechanism. I’m thinking that if he did, he’d notice that it quite securely held itself. But that doesn’t come up in his text. It makes me think that he used the pictured version.
Fair point, Roo - but it raises an interesting question (we may never know the answer) - although Ashley may have tied knots in order to draw them did he actually use many (or any) of the practical knots he shows? In this case he undoubtedly saw the knot in use but my feeling is that, like many others, he never used this knot in a real situation. Of course I may be quite wrong but I can tie and describe any number of knots which I have never actually used other than as an armchair knotter and probably never will so I may never be fully aware of the real advantages/disadvantages of a particular knot. Add to that the propensity of authors to parrot what went earlier you begin to wonder just how much of the received wisdom actually relates to the real world. That I hasten to add does not apply to the versatackle which is a well tried and useful arrangement though I normally add a redundant half hitch “to be sure, to be sure” especially in slippery polypropylene.
Barry
"....One or several turns are made through the two loops [b]and they are tightened at every turn[/b]."Frankly, I find this assertion (and were it advice ...) dubious: tightening at each added reeving doesn't make sense to me; I can see the act maybe as simply an attempt at getting greater tension, but at a cost of any real MA --otherwise, I'd think that if multi-reeved MA were wanted, they'd make the turns [u]and then[/u] haul the tail to tighten it at once. (Either way, one is likely to see slack in early reevings with a subsequent one tightened, and friction will make evening the tensions difficult.)
I might be who has illustrated and “fiddled”
the most knots of anyone --I’m a candidate,
for sure (as is X., Pieter van de Griend, and
some others) : I can --like you-- assure you
that many of these knots are met with only
briefly, in the moment of exploration, and
never much used, if at all (sometimes, the
familiarity is so passing that the knot gets
"re-"invented by me! 
) Beyond this,
one can have illustrated a knot, even used
a knot, and be unaware of some if its properties
(e.g., I imagine that most of the kernmantle
rope users who “know” the bowline with
Yosemite tie-off don’t realize that it can be tied
in the bight (which isn’t even a possibility if
one is tying in for climbing, where TIB is
impossible)).
In the OP case, I would hold Ashley derelict in
his explanatory duty were he to have been aware
of the versatackle reeving to provide for self-locking
(even if taken as momentary, in need of tie-off)
and not to have mentioned that.
–dl*
The Versatackle or Versitackle (can’t remember) was devised by George Aldridge of the London Knot Tyers and I am pretty sure it was published in Knotting Matters. It is in regular use, as originally presented, by me and I suspect by others after one of my many demonstrations of this clever construction.