This was sailing. So they were mostly for hitting each other with. As is traditional.
A weight is generally unnecessary if you tie it large enough, except in high winds. Which is easier with thicker boating lines. It’s more common to keep a pre-tied one on a loop, attach it to the line to be thrown. So it can be heavier than a thin line provides, and you don’t have to tie a complex knot on a rolling boat. Those big ones were usually tied around a fishing sinker.
You can also tie a monkeys-fist around a ball of cork - sometimes used a the bitter end of a line so that you can get it back if some lubber loses his grip. The AUV operators also use monkeys-fists with cork on all sorts of underwater tools to provide something for the grapples on the AUV to grab onto.
Fun fact is that many varieties of paracord float. So a monkeys fist tied in it can stand in for a float on items like crab traps. It’s hard to spot for hotel traps, but for the sort of box and ring traps that close when you pull them it can work in a pinch.
In addition to the other answers, it’s a useful knot on the end of a lanyard with your keys on the other, especially if it’s weighted. A number of times my keys have slipped out of a shallow pocket while I’ve been sat down, but the weight on the other end has stopped them falling further, plus it’s a solid item to grab hold of first.
On the end of a foot or eighteen inches of paracord it could give someone a hefty sack on the head or something under certain circumstances…
Heh. I’ve pulled a lot of crab traps, but not in many decades. I remember either tying the bitter end of the line off on something like a dock, or else putting a cork float on it. I don’t recall anyone using floaty rope - the only place I ever saw that was the polypro lines that marked off the sections at the municipal swimming pool. Then again, everything was whatever we could get our hands on - the traps were chickenwire or fish net stapled to a wood lattice, as often as not. The wire and staples didn’t last forever, but you could get quite a few crabs before the stuff rusted away, even in salt water.
Then again, crabs from where I used to catch them fall in the category of, “wouldn’t dare eat nowadays, but back then, who knew?”
I can recall a whole series of weird dad conversations on one business trip, triggered by the fact that I’d absentmindedly left a 'biner clipped to my backpack. Lots of other whackos noticed that it was a real one, not one of those ‘NOT FOR CLIMBING’ key chains and struck up weird conversations.
You generally don’t want to. In current it can pull the doors shut, and it’s likely to get tangled in boat props.
But it can pull double duty as float and something to hook when you’re not dropping them off structure. Provided the line doesn’t sink when water logged. Which paracord won’t. Also it doesn’t rot.
My brother improvises fishing bobbers from it.
ETA: the right way to do this is to tie a monkeys fist in a short section of floaty paracord with a loop or two in it. Then connect that to line that will sink properly. The fist can be tied around a chunk of pool noodle, which is cheap and won’t rot like cork.
The lazy way is to rig your box traps with paracord you don’t know will float, and just roll with it.
To get a line over a branch I carry a small nylon drawstring throw bag. The rope pays out better. Of course one can always put a rock or even a handful of sand in the bag when one is sick and tired of stuffing the rope back in for the umpteenth %$@&* time.
I use a PCT hang. More often than not, the 'biner is enough weight. I’ll only resort to a rock if the branch is at a really awkward angle or it’s really windy.
I french the line down before I heave it. Never had a problem with it paying out. Except for the one time that I used a higher branch than usual, and watched the bitter end follow the rest of the line over the branch. I was so glad nobody was watching me for that one!
what teknocholer said. I learned it as a “Braided button” (from Ashley’s, I believe). I liked it because it was easier to learn and work than a monkeys fist.
For people who are not adults, I would recommend caution and previewing knot websites… there are applications which are perhaps more… interesting… than others.
Thank you so very much! As a professional Able Bodied Seaman–Unlimited, I was filled with umbrage by the misnomer. Typically, we employ the Monkey’s Fist, at the end of a heaving line, to messenger the ship’s mooring line to the longshoremen and the bollards on the dock.
To be honest, the MF has been falling out of use, due to the dense mass (often with a large metal nut as the core) presenting a dangerous threat to the person receiving it ashore. That and the potential of damaging a hapless vehicle parked within striking distance on the dock. Gotta be nice to our ILWU brothers ashore.
We currently prefer taking a cut length of fire hose stitched and filled with sand, with a means of attaching to the heaving line. Much softer. These fly just as far when wielded by skilled hands.
BTW, the great classic book on knots is Ashley’s Book of Knots. Buy it, learn knots, and make your own YouTube videos–but with the 'effin correct names!