Loops

Knots and Rope Work

Course 1 · Chapter 4 · Loops: Bowline, Figure-Eight Loop and Alpine Butterfly

A fixed loop is a loop that keeps its size however you pull on it. Loops let you hang a rope on a post, clip it to a ring, or give someone a handle. Three loops cover most needs: the bowline at the end of a rope, the figure-eight loop for a heavier or more trusted job, and the alpine butterfly for a loop in the middle.

What Makes a Good Loop

It does not slip. The loop stays the same size under load, unlike a slip knot or noose.
It unties afterwards. A good loop can still be undone after taking a heavy load.
It is easy to check. You can see at a glance whether it is tied correctly.
It suits the place. Some loops go in the end, some in the middle, and a few can be tied around an object.

The Bowline

The bowline is the classic end loop, popular on boats and around the home. It is quick to tie, holds well under steady load and usually unties easily. A well-known weakness is that it can work loose if the rope is shaken, slack or loaded from the wrong side. (Details of its failure modes: check.)

Make a small loop in the standing part, with the end on top. This loop becomes the "rabbit hole".
Pass the end up through the little loop, as if the rabbit comes out of the hole.
Take the end behind the standing part, the "tree".
Bring it back down into the little loop, the way it came out.
Hold the end and the loop strand together, and pull the standing part to snug the knot.

# bowline, in words (the rabbit story)
make a small loop in the standing part, end on top    (the hole)
pass the end up through the hole                      (rabbit out)
take the end behind the standing part              (round the tree)
bring the end back down the hole                    (rabbit in)
pull the standing part to tighten

# result: a fixed loop in the end of the rope

Leave a tail Tie a stopper in the tail, or at least leave a generous tail past the knot, so the bowline cannot shake loose. Backing up a knot with a stopper is the habit from Chapter 3.

The Figure-Eight Loop

The figure-eight loop is the figure-eight stopper from Chapter 3, tied as a loop. It is bulkier than the bowline, but it is very easy to check by eye and is less likely to loosen, which is why it is common where a mistake would matter. It is tied either "on the bight" (a doubled section of rope) or by retracing the figure-eight around an object.

Double the rope to make a bight, about a hand's length long.
Treat the bight as a single strand and tie a figure-eight with it.
Check that the two strands lie side by side, never crossed.
Pull snug. The bight is now your loop.

# figure-eight loop (on the bight), in words
1. fold the rope to make a doubled section (a bight)
2. tie a figure-eight, using both strands as one
3. check the strands run parallel, not crossed
4. pull snug

# result: a fixed loop, easy to inspect, slightly bulky

The Alpine Butterfly

The alpine butterfly makes a fixed loop in the middle of a rope without needing to reach an end. It can be loaded in several directions, and is used to isolate a worn or damaged patch of rope or to add a clip-in point partway along a line. (Specific uses in climbing and rescue: check.)

Make a loop in the middle of the rope, then twist it over to make a second crossing.
Fold the top of the loop down behind the crossing.
Bring the folded part up through the gap at the front.
Pull the new loop and both ends to tighten.

# alpine butterfly, in words
1. make a loop in the middle, twist it once to cross
2. fold the top of the loop down behind the crossing
3. bring the folded part up through the front gap
4. pull the loop and both ends snug

# result: a fixed loop mid-rope, loadable along the line

Loop	Where tied	Strength	Weakness
Bowline	End of rope	Quick, unties easily	Can shake loose
Figure-eight loop	End of rope, or on a bight	Easy to check, secure	Bulky, harder to untie
Alpine butterfly	Middle of rope	Needs no free end	Takes practice to tie neatly

Loops and people A loop tied for practice is not safe to trust with a person's weight. Anything where a fall or injury is possible needs proper instruction and equipment, which Chapter 9 introduces. (Whether each loop is accepted for a given activity: check.)

Not Yet Verified, and Sources

Source. Written from general knowledge of common knot practice; no specific source was read, and nothing is quoted from a text.
Marked (check). The bowline's failure modes, climbing and rescue uses of the butterfly, and what each loop is accepted for.
Descriptions. The steps are in words and the "rabbit" story is only one of several mnemonics. Follow with real rope and adjust to what you see.

Exercises

Exercise 1

Tie a bowline around a chair leg or post. Load it by pulling steadily, then shake the rope while it is slack. Does it hold its shape? Write down what you notice and how a stopper in the tail changes things.

→ Solution

Exercise 2

Tie a figure-eight loop on the bight and a bowline in similar cord. Compare how easy each is to check by eye, and how hard each is to untie after pulling hard.

→ Solution

Exercise 3

Tie an alpine butterfly in the middle of a length of cord. Hook a finger through the loop and pull in three directions: along the rope each way and out sideways. Describe what happens, and name one job where a mid-rope loop is useful.

→ Solution

Quick Reference

Fixed loop: a loop that keeps its size under load
Bowline: quick end loop, unties easily, can shake loose
Figure-eight loop: secure, easy to inspect, bulky
Alpine butterfly: a loop in the middle of a rope
Back up with a tail or stopper; practice loops are not for people's weight

Coming next Chapter 5 moves on to bends: joining two ropes with the reef knot, the sheet bend and the double fisherman's.