On the second attachment it says: "The prusik knot will always hold better if it is right side up as shown below"
That is [BS] . This is the same as saying: The Prusik with the loop sticking out on the right hand side performs better then the Prusik with the loop on the left hand side. It doesn't. Its the same knot!
> The prusik is symetrical. It works both ways equally well, as there is no difference.
Such language is unwanted here (except by intimation/abbreviation),
and is especially unfortunate when it is so clearly wrong. You might
take care in faulting something expressly stated (i.e., that suggests
that the particular point was considered, not incidentally involved).
Now, how ... different?! -- in how the coils are oriented with regard
to the lay of the rope!
Yes, that is a 1961 presentation, and the
ropes du jour were laid nylon Plymouth Goldline and various other manila
(ideally, much less elastic!) ropes. In the given image, the "better"
orientation of the Prusik hitch
shows the upper, *coil-away*
half of the knot wrapping against
the lay, the lower ... with.
Interestingly, the Prusik
shown is a "4-coil" (2x2); today, I think
that the 5-coil version is more commonly used, and especially the
coil-away half benefits from more wraps, as it will extend to grip.
The Penberthy [hitch] seems to be nothing more than a bowline (or eskimo bowline in the other variation)
with the loop wrapped several times around the rope before finished.
Basically using the bowline as a hitch with several round turns.
One can do the same with any fixed loop.
But one cannot so easily adjust the coils and then
tie the eyeknot
if using an eyeknot (e.g., fig.8 )
that needs to have some *pre-knot*
tied awaiting the tail's completion.
Furthermore: the Prusik does not jam one bit.Pie in the sky
As soon as the load is off, it can be moved along the rope as easy as pie.
opining here; history (and much usage with
the knot in various circumstances) speaks strongly otherwise.
Do you really think that cavers and arborists --users who depend (or
have done so, before mechanical devices (Jumars)) on hitches to
move up (and down) ropes-- cannot assess these knots, and could
be so wrong about one of the oldest-in-use of them?!