If You Only Learn To Tie One Knot...

...Make it the figure eight knot. This is a very versatile and relatively strong knot that's easy to learn and execute. With just a little variation, it can function as a stopper, a bend, a hitch and a loop.

The basic form of the figure eight knot (shown above) is meant to act as a stopper, to keep a rope from running out of another knot or a retaining device. It's superior to an overhand knot in that it doesn't bind under stress and can be untied when it's no longer needed. An overhand knot, on the other hand, will often be locked tight, requiring it to be cut off, rather than untied. The figure eight knot also retains more of the rope's breaking strength (roughly 75%), compared to the overhand knot, which nearly halves the strength of the rope.

By tying the figure eight knot on a bight, you create a strong, usable loop in the end of your rope. Functionally, it's identical to a bowline, but retains slightly more breaking strength than the bowline, with less chance of the knot slipping out.

To make a hitch, you start with a basic figure eight knot, but don't tighten it yet. You then feed the working end around the object to which you want to tie the hitch and retrace the knot with the working end before finally cinching the knot tight. This is known as the figure eight follow through. The end result looks like a figure eight on a bight, but the loop is around an object that you might not otherwise be able to put the loop around.

Using the same concept as the follow-through knot, you can join two ropes together, known as a bend. Again, you start out with a loose basic figure eight. Then, instead of using the working end of the same rope for the follow through, you retrace the knot with the working end of your second rope and finally cinch it tight.

Some Things to Consider

It's not enough to simply tie a knot and let it be. When tightening your knots you need to make sure they are properly dressed. This means that the knot is pulled tight before it's loaded, that it looks even and symmetrical, and that parallel lines don't cross inside the knot. It has to look pretty if it's going to function to the best of its abilities and not cause the rope to fail. You need to check knots periodically, too, to make sure they aren't deforming or slipping out. This goes for any knot; not just the figure eight.

The figure eight is a very capable and versatile knot that will allow you to do a lot of things with a rope. But it's not always the best choice. There are hundreds of different knots that you can learn, some of which are better suited than the simple figure eight for certain tasks. And there are things that other knots can do for you that the figure eight simply cannot. So to be best prepared, you're better off not to stop at learning just the figure eight knot. Learn it, use it, and marvel at its simplicity and versatility. Then learn other knots that will allow you to do even more with your rope. An excellent online source for learning different knots is Animated Knots By Grog.

A note on safety: Ropes are wonderful tools that allow you to do a lot of things. But they have their limits. They will break if overloaded or mistreated. Take care of your ropes and be mindful of what you do with them. Stay safe!