Yes the ones shaped like an 8 or with a solid bar were not liked very much by their captors..I f the prisioner had to relieve himself, the guard had to help him, or unlock them and let him do his own buisness at hand....
Check out the pictures, though (hope the links work, was having trouble with some when I was posting yesterday). The "8" or solid bar chains, at least the southern ones I'm aware of, were generally long ones, designed for convenience of movement, for men to wear when being conducted on foot in coffles. From the appearance, and from common sense based on coffle drivers wanting to make their job easier and safer, I
think one could relieve oneself while wearing them, not that I've ever worn them, thank god!
I suspect the design was primarily to reduce the number of welds, since they'd be forge-welded individually with hammer and anvil, so a series of longer links would be almost as flexible as a regular chain, but require half or a quarter or less of the number of welds.
Do you have images or info on solid-bar short handcuffs and their use in the period? The various name-brand law enforcement handcuffs I've seen, like the ones in the linked images, have a couple flexible links between the cuffs, so I haven't run across that form specifically, but I'm sure they were around, since they'd be similar in concept to the stocks and yokes in the south.
And, uh, because I realize it sounds like I care way too much about this, LOL! No, I'm not into bondage or anything. Needed to research this a while back to see what former enslaved people and masters were talking about when they referred to various forms of confinement, and get a clear enough mental picture to decide when they were writing from first-hand experience or copying and exaggerating to make things sound better or worse.