Triple Fisherman's Knot
This is the knot most rock and tree climbers use to make homemade prusik loops. It's excellent for connecting two ropes together, but the prusik loop thing is where it's at. The Fisherman's knot is very secure and when you add additional wraps to the single or double, its security is strengthened even more.
For this example, I'll use two different colored ropes and combine them as one. I figure the different colors will make my demonstration more clear.
To start off, I'll place both ends of the ropes on a table, end to end and next to one another.
Then, I take the working end of one rope and place if over the other rope.
I'll give the other rope a wrap.
And then a second wrap. And a third wrap after that.
After that, I'll take the working end of the rope and, making sure to pass over its own standing part, feed it under both wraps, up and out the top.
To tighten the knot, I'll pull both ends of the rope.
To finish this knot, I'll follow the same instructions for the other rope. For my example, I basically attached the orange rope to the black and the black to the orange. Take a look.
When the two ropes are pulled away from one another, the knots come in contact with each other. These knots are strong!