Loops by Type
There are many different loop knots to choose from. You can tie a loop at the end of a rope or in the middle. It can slide like a noose or be locked in place, or even have multiple turns.
A locked fixed loop does not slide and keeps its size when strain is placed on it. Once a locked loop is tied, it can be thrown over a peg or hook to secure the rope, and then lifted off and used again. If tied for a handhold or around your waist, it will not close down on you. The Bowline Loop is probably the most well known of this form. Some locked loops are made by splicing a three-stranded rope and using the strands to tie the loop.
When you need more than one loop, you can tie a knot with multiple loops. Complexly shaped objects can be hoisted without tilting, and a single rope can be fastened to multiple anchor points. Loops can even be different sizes. If you need a large number of custom-sized loops for hoisting or binding, you can start with a small fixed loop with a large running end left over. Repeatedly make your loops with the running end, passing it through the locked loop each time, tying off the last one.
The Hangman's Noose is a popular knot but should never be toyed with. Children may try to re-enact how they see them used in TV Westerns, with tragic results.
You may need a loop that is adjustable in size. Sliding loops, also called nooses or slip loops, fill this purpose. Fishermen often want a loop that will hold its shape until just enough pressure is put on it, causing it to pull down with a jerk that sets a hook in a fish. Sometimes you just want your loop to fit something snugly, but need to tie it ahead of time. If you have a fixed loop and need to make it larger, you can just pull a bight of the standing part through the loop, giving you as large of a loop as needed. An example of this is the Running Bowline.
There is a world of loop knots to choose from, and even if you prefer to remember just one locked loop, you can make a sliding loop or a multiple loop from it. Loop knots are rewarding to learn and tie, and rope becomes quite a diverse tool when you learn them.