Like the "Waterman Knot" above, the use of the fisherman knot is similar. It is used to tie two ends of rope together, but that is where the similarity ends. As you will see below, it is tied in a completely different way. The "Fisherman Knot" is useful for tying two ropes together for the purpose of rappelling often times. This allows two - 50 or 60 meter ropes to be tied together. This allows the mountaineer to rappel over 150 feet and still be able to retrieve his rope. The "Fisherman Knot" is also used for tying narrow diameter rope together for protection purposes and also for short loops of rope that can be used to prusik up a fixed line for ascending purposes. The four step process of the Fisherman Knot is shown below.
Lay the two ends of the ropes side by side as shown.
Next, coil a couple of loops around the opposing rope lengths on each side. The more the coils the more secure the knot. Two to three coils should be more than sufficient.
Now complete your last coil and then feed the end of each rope through it's own coils from the inside out. This way when the knots slide together they will press against each other to provide lots of friction. This will eliminate slippage under most normal loads.
All is left to do now is to pull the opposing ends of rope and slide the opposing knots together. Once this is done take time to dress up the coils and make sure you have a few inches of rope free on each side as shown. This will give you a bit of extra security just in case there is a small amount of slippage under load. Shown above is a two coil fisherman knot, but mentioned above, three, four, or more coils could be used if more friction is desired.