Round turn and 2 half hitches is possibly the most useful knot with reef knot using one or two ropes/cords. However I see the half hitches often get done wrong.
*snip*
Sorry to interrupt... You need to be careful with the reef knot, it tends to spill under load.
The reef knot was the knot used to reef sails, NEVER use it as a bend.
Clifford Warren Ashley, can be quoted. Cyrus Lawrence Day has repeated the warning by Ashley... I'm sure the list goes on.
Being curious I tested it myself: My 5? samples with jute all spilled at low levels of force (Edit: or rather every knot spilled before the twine broke).
A loop of single paracord gut got up to 15 kg (much to my surprise), due to the sealed ends...
With cut ends the paracord gut loop was 5 Kg ...
If you want to tie a knot under tension, that usually needs a hitch.
If you want to tie two ends together, use a bend...
And if your really really stuck right now: Try a fisherman's bend? (Water knot, Waterman's, English, Englishman's, True-Lovers, Angler's knot).
Ashley book of knot page 259, ABOK #1414. Or look it up on your favorite source...
ah here is a colour picture for easy reference, this is the knot.
This knot is really simple: It's easy to tie and easy to adjust... It's also strong and secure... So far so good.
Now take this idea with a cup salt: "You can slip the ends to make a quick release?"
This is knot heresy! It could be extremely dangerous.
The two slipped ends, form loops like a bow, inline with the cordage. While the two free ends are perpendicular. I think it looks very very neat.
I've tied a few loops in jute twine and one using a single strand of paracord guts. I've ripped these apart with destructive testing, this is not precise science or good statistics. But I can easily (with the jute) or reasonably (with the paracord guts) pull the quick release to untie these after I'm tightened these knots as tight as they will go. (I've been blasting a few knots and making notes on untying the remains lately...)
When joining to ends together to create a loop, you tie one end then adjust the size of main loop. Tie the other end to finish. Thus you have a heavy duty, yet reusable "bush craft zip-tie" with quick release. Another trick would be to have a turn or two (loop-the-loop the package with the cord): Now, not only are you compressing the package down, the cord can't back off and any little slack that creeps in as you tie the second side can be divided by the number of turns.
The only slight downside is that the fisherman's bend isn't up the top in terms of strength, at least according to Ashley. Ashley had his own rigs for repeated testing. My static test results may vary: I'm happy with my results.
My few results used luggage scales... However I feel the 31 Kg for a loop of single strand paracord guts is more than enough for my testing. I'd expect anything from 28 to 35 lbf with age, wear, and dozens of other real world problems are going to eat into the lab result. So my 31 kg for the loop would be 34.141 lb for a single. I have also compared the Barrel knot (#1413, also Page 259) which came out top in Ashley's testing. (Ashley's testing setup is on pages 16 and 17, and the test results table on page 273).