Knots

Square knot -- In sewing, important mainly as the basis of the Surgeon's Knot and the Bow Knot. The square knot is a binding knot, used when you want to leave tension on the ends being joined. If tension won't be applied until after the knot is finished, tie a bend.

Surgeon's Knot -- used when a square knot would loosen before you can tie the second half. Wrap the first twist two or more times instead of once, then put your finger on the twists while forming the second half hitch. If there is a lot of strain on the line being tied, you'll have to make so many twists that the second half-hitch can't settle properly; in this case, make a third half hitch so that there is a square knot sitting on the twists.

Bow Knot -- a square knot that is easily undone. Make the second twist with the bights of the thread, instead of the ends.

Half Hitch -- a buttonhole stitch. Topologically equivalent to half a square knot, as you can see by tying half a square knot, then straightening one of the strings. There are two half hitches, one equivalant to the Overhand Knot, and one equivalent to the Underhand Knot. If you are making only one half hitch, it doesn't matter which, but when you make several, you usually want to make them all the same (as when working buttonhole stitch) or want to alternate them (as when tatting, tying square knots, or working Up and Down buttonhole stitch).

Clove hitch -- for closing storage bags and any other time you want to bind something tightly. Also called "scaffold hitch".
Wrap the string around the bag twice, ending with the two ends in your hands and one strand crossing the bag on the side next to you. Tuck the upper end of the string down under the crossing strand, then tuck the lower end up under the crossing strand, so that it comes out between the crossing strand and the upper strand. (The upper strand now comes out between the crossing strand and the lower strand.) Pull both ends to close the bag.

Bow clove hitch -- to make the bag easy to open again, tuck a bight instead of one of the ends. You end up with a single loop, and the ends lie side-by-side. I find it easier to make the upper end into a loop -- perhaps because I habitually have that one in my right hand. Anyway, it leaves the ends pointing up for easy package opening.

Reef Knot -- another name for Square Knot

Sheet bend -- also known as weaver's knot. A "bend" is a knot for joining two lines. The sheet bend is quite popular because it is easy to learn, easy to tie, and easy to untie. It's particularly good for joining lines of unequal thickness: the thicker line should be the one that makes a simple U-turn through the knot. If you learn the square knot, clove hitch, and sheet bend, you will be equipped for most situations.

Bowline -- a loop made by tying an end to its own standing part with a sheet bend. If you learn the sheet bend, you get the bowline free.

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I can't draw worth a nickel -- Google for the excellent illustrations, some of them animated, that boy-scout troups post on the Web, or look up these knots in Wikipedia.

I don't think either source will tell you how to tie a Zeppelin bend; I'd never heard of it until I asked on rec.crafts.knots for the best way to tie the ends of cord elastic to be sewn into a casing. Airship captains insisted on it for life-critical mooring lines, and it's good for knots that you would have to cut stitches to re-tie. It looks rather like a symmetrical sheet bend; that is, you tie the loopy side to another loopy side instead of to a U-turn. There is a clear illustration at http://notableknotindex.webs.com/Zeppelin.html

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