A tight hitch is not a hitch that becomes tight while it is loaded !

ALL secure hitches and nooses will become
very tight, while they will be loaded by a
very heavy load - as long as this load remains in place. The tensile forces that are induced into the knot by the pull of the standing end, will be transferred to the round turns, and the round turns, by their turn, will grip the pole. The stronger the pull, the stronger the grip on the pole, and the tighter the hitch will become. However, in most hitches, the moment the load will be reduced or removed, the round turns will not grip the pole as tight as before.
A tight hitch is a hitch that remains as tight as it became when it was loaded - even after the initial load is reduced or removed. So, a tight hitch is a hitch that, once heavily loaded, will never lose its strong grip on the pole.
To achieve this effect,
a hitch should incorporate some locking mechanism of the standing end.
That is what Ashley missed, because, if we read his book carefully, we will see that he is trying to figure out all the conceivable ways to secure the tail - and not the standing end ! He tries to tie
secure hitches, not
tight hitches. If a secure hitch happens to be tight as well - in the sense described above - he acknowledges it, but his main purpose is security, not tightness. No wonder that his lengthwise-pulled hitches , in Chapter 22, are few and mediocre ( with the only exception of the #1755-6, which is based on another, very different gripping mechanism ). I have seen that a
pre-tightened hitch will be able to withstand a subsequent lengthwise pull much better, for reasons that are still not very clear to me.
Of course, Ashley is Ashley - he is the inventor of the Constrictor, one of the tightest knots we have. However, the Constrictor is meant to be a binding knot, not a "proper" hitch, so, if used as a hitch, it has its drawbacks. It can be severely deformed if the direction of the pull is not perpendicular to the axis of the pole and tangent to its surface - much more than the less tight Strangle knot.
A proof that Ashley was not concerned with the issue of securing the standing end, is the ABoK#1683, where the tail of a Cow hitch is secured by making a U turn and going under the two riding turns. This way the Cow hitch is transformed onto a very secure hitch, indeed. However, if Ashley had in his mind ways to secure not only the tail, but also the standing end, he would have made the small step to pass the tail not omly under the riding turns, but under the standing end as well - and he would have tied the tight "Locked Cow hitch", where the standing end is nipped in between the two opposed U-shaped bights, the one of the round turns and the second of the tail.
I will not discuss here the minor issue, if the ABoK#1683 hitch and the locked Cow hitch are two variations of the same knot, or two different knots. I believe that, although they look so similar, they are two different knots - because the later incorporates one more mechanism that the former does not : the mechanism that secures the standing end, allows any accumulated tensile forces that are induced and stored into the hitch to be kept locked, and so allows the hitch itself to remain as tight as it became when it was loaded, even if /when the initial loading is reduced or removed.
Of course, if Ashley had understood the significance of securing the standing end, and if he would had tied the Locked Cow hitch, he would also had tied the Double Cow hitch, with 4 or 6 wraps, and he would had enriched his Chapter 22 with a hitch greatly superior to the few mediocre hitches presented there.
If we attempt to classify the hitches according to the mechanism by which the standing end is locked in place, we can possibly distinguish the following 5 classes :
[The standing end is secured by passing] :
1. Under a riding turn. (Clove hitch, Constrictor knot, almost all ABoK s hitches and binding knots ! )
2. Through a bight, in contact with the surface of the pole. ( Cow hitch, ABoK#1683 )
3. Through an overhand knot, a fig. 8 knot , or any other nipping structure ( "simplest hitch" , nooses, arthroscopic lockable knots )
4. Through a nipping loop
( Through an *O*) ( simple hitch a-la-Gleipnir )
5. Through a bight and a segment of the rope perpendicular to its legs
( Through an *A*)( Andalusian hitch, Locked Cow hitch)
6. Through two opposing bights
( Through two *U* s) ( 2 U s hitches, Double Cow hitch, dL s S hitch, TackleClamp hitch )
I might well have missed something - so the reader who will spot a hitch where the locking of the standing end belongs to a different kind of mechanism, is kindly requested to report it here.
P.S. Of course, the not-at-all-never-ever-interested reader will keep parroting that all those hitches belong to the "
countless tangles" that have been already
" looked", " evaluated", and discarded/rejected for
"real practical use" , by
"knot-enthousiasts". I hope that Ashley, in after life, will
forgive all those
" knot-ethousiasts" ...

I am sure that, if he was still with us, he would be glad to tie all those new tight hitches - and then some !