What is this adjustable hitch?

[Knicknack]

you can add grip of the hitch by adding some initial rounds.

Not sure what I'm looking at here.  Does this arrangement put the coils in compression?

[mcjtom]

You may be interested in p. 266 of the ABoK as a few constructs there are not that dissimilar from your hitch.  It's easy to overlook as it's in the bends section.

p.s. Also from personal, admittedly not well tested, experience I find Blake's hitch sans one turn (which I think is the same as #1470 with an extra turn) to work reasonably well on many types of utility ropes and cords.  The second last turn can be tucked under the last one in the Midshipman's fashion, which may (or may not) increase its grippiness.  There can also be at least 2 variations of it, depending if the final tail tuck is under one or two initial coils - I'm not sure which one works better - common sense suggest that the former may be better for slick ropes and the latter for stiff ones, but ropes may not be aware of it...

In this gripping hitch the coils are under tension, just like in gripping Sailor's or Icicle hitch when being pulled in the 'right' parallel direction, which I think may be more effective than piling them on top of each other as in e.g. Camel hitch or the Tautline.

[jarnos]

Not sure what I'm looking at here.  Does this arrangement put the coils in compression?

I think it adds some elbow to the standing part. One extra turn might suffice. Using the bight ending adds some turning, too.

By the way, the knot seems to have good grip even when only two of the three legs of the of the knob are loaded. By legs I mean the legs of the loop and the working part.

[Knicknack]

You may be interested in p. 266 of the ABoK as a few constructs there are not that dissimilar from your hitch.

Might still be early to be calling it my hitch, but yes, quite similar in appearance, and not just those.  Some in this thread have pointed out other near look-alikes.  There are a large number of hitches which have the general form of a line-in, a line-out, and two wraps, with all the variation being in which passes go over, under, or through others, or on which side of the object rope they pass.  And you have to figure that for each one of those that made it into general circulation, many more were tried.  This is a very well-developed space, so I started this thread with the expectation that this would turn out to be a known hitch--even if I couldn't understand, if it was known, why it wasn't well-known.

And I'm also not requiring an exact match.  A mirror-form would obviously count as the same knot for example.  You can also have augmented forms (as you noted, adding turns to Ashley's basic #1470), degraded forms (a bowline with the tail to the outside, or a Carrick with the ends on the same side, or a sheet bend with the ends on opposite sides) and derivative forms (where a pass difference doesn't appreciably change the overall function).  But it is also quite common for a small difference in structure to result in a large difference in characteristics.  A square knot and a granny knot are significantly different, as is a clove hitch and a constrictor knot.  But the matter of when differences are large enough to be considered significant is a grey area, which was another reason I thought it best to consult the experts.

In this gripping hitch the coils are under tension, just like in gripping Sailor's or Icicle hitch

Coils typically resist sliding by constricting around the object rope.  I don't think this hitch operates by that principle.  It seems to operate more in a wedging fashion, like roller clutches.  I think that's why it has such a remarkably low threshold at which auto-tightening will engage, and why it releases so easily.  I haven't experimented with adding coils (on my ropes here, it doesn't slip), but just for purposes of identification, I figure the simplest basic version is the preferred way to go.

[mcjtom]

As a point of interest: there is an arthroscopic knot published by a Thai Uni that relies on similar mechanics.  I also think is not that different from the working of HFP Slippery 8.  https://www.sciencedirect.com/science/article/pii/S2212628714000541

There is also a discussion started by Xarax on arthroscopic knots used on ropes as friction hitches here.  I can't find an example of the hitch that started this discussion, but there is a plethora of publications on arthroscopic knots which is one of the few active knot research fields - perhaps it's hiding somewhere there... https://igkt.net/sm/index.php?topic=4107.0

[Knicknack]

As a point of interest: there is an arthroscopic knot published by a Thai Uni that relies on similar mechanics.

Yes, another in that general area.  But the Chula is two passes different from this hitch.  There is another hitch I use (a friction-multiplier hitch) that is right in-between--one pass different from the Chula, and one pass different from this hitch.  But that one pass difference makes a huge difference in the way it works.

I also think is not that different from the working of HFP Slippery 8.

There is no wedging element in that knot.  On my ropes here, the name "slippery" is apt.

there is a plethora of publications on arthroscopic knots which is one of the few active knot research fields - perhaps it's hiding somewhere there...

SS369 made basically the same suggestion at reply 11.  Having now examined about a dozen such knots, and looking at what they are designed to do, my sense is that this hitch would not make a very good arthroscopic knot.  So I would be surprised if anyone is using it for that purpose when there are so many better candidates available.

[mcjtom]

...my sense is that this hitch would not make a very good arthroscopic knot.

I think that for many arthroscopic knots the idea is that they need to slide down the loop and then 'lock' (capsize) by pulling the tail, rather than continue being adjustable.  The Chula seems to do that quite nicely given its simple form.

There is no wedging element in that knot.

There isn't in the Slippery 8, but there isn't either in the Chula, until it's locked.

There is another hitch I use (a friction-multiplier hitch) that is right in-between--one pass different from the Chula, and one pass different from this hitch.

Could you show or describe it?

[Knicknack]

There is another hitch I use (a friction-multiplier hitch) that is right in-between

Could you show or describe it?

Sure. First image shows side-by-side the progression from the Chula, to that particular friction-multiplier, to the as-yet-unnamed adjustable hitch.

Second image show this FM hitch coupled with a lobster buoy hitch (#1714) as the root hitch which will provide the friction to be multiplied.  Actually, the lobster buoy itself can serve as a less-aggressive friction-multiplier, but on some of my ropes even three LB's in row aren't enough.  The configuration on the left shows it in a progressive mode, where the hitches can still be slid (in the direction of load) under low loads.  As the load increases it will grip tighter to compensate.  The configuration on the right is same hitch turned up-side down.  This is not progressive, but it is a good emergency backstop.  Both of those configurations are ready-to-go as depicted.  They do not need to be dressed or made any tighter than shown prior to loading. The panic-stop config will engage and hold almost instantly even under a hard jerk (-on my ropes.  I've never tried these on super-slippery ropes.)

Ashley mentions what he calls "jamming hitches" (pg. 325) which can slide very easily when loose, and then you lock them by giving a firm tug on the free end.  These have a similar function, except it is the load itself which activates them.

[mcjtom]

Many thanks for this!  BTW, awesome photography - any tips as to how to achieve similar effect?  Cheers!

[Knicknack]

BTW, awesome photography - any tips as to how to achieve similar effect?

Really? I was just going for clarity. I would never have guessed that "starkly utilitarian" was a style. 

Okay, well, it's definitely not a difficult style to duplicate if you have the right equipment.  I arrived at it by being the sort of person who favors solutions that are simple, easy, and get the job done--even if they are sometimes a little unorthodox.  So when the digital camera is busted, but the flatbed scanner works...

(Okay, I also do a little post-processing to clean the scans up.  I leave the lid up for a background that is dark enough it can be auto-selected, then turn it full black.  And my Epson scanner has a slight top-lighting bias, so if I think underlit would be clearer, I rotate the rope on the bed, then unrotate in post.)

[mcjtom]

Works the trick!  I never thought about using a scanner for the purpose thinking that the depth of field would be way too shallow... Making them monochrome and collapsing the background to solid black also help as the images can have larger pixel size and not that much jpeg compression and still fit the 100 kB limit of this board.

It's refreshing to see simple and timely yet succinct and helpful illustrations of knots being discussed instead of torrents of words.

[Knicknack]

I never thought about using a scanner for the purpose thinking that the depth of field would be way too shallow...

It's not as bad as it used to be, but you've still only got about a quarter inch of clearest depth.  Even so, the focus falloff rate isn't terrible.  The rope in the attached image had parts over an inch off the deck.  Not that much worse than for macro photography.  Good enough for purposes of illustration--though I usually prefer to expand and flatten out the knots anyway, just to make the paths easier to follow. (Though that doesn't work when trying to show the optimal dressing configuration.)

Side lighting was provided by a flashlight. One nice thing is that if you don't move the rope, repeat scans have perfect registry, so if you want to play around with lighting effects, you can merge and blend just the bits you want from multiple scans.

It's refreshing to see simple and timely yet succinct and helpful illustrations of knots being discussed instead of torrents of words.

I like clear pictures and simple text, because I tend to think visually, and not so much in words.  My mother had a very linguistic way of thinking, and she struggled to interpret images I thought were very simple and clear, but she could easily follow what seemed like convoluted speech to me. So the wordy descriptive posts might not be my style, but I can understand why other people might prefer them.