If you only learn one knot make it the marlin spike hitch. It's simple to tie and leads you right into 4 other great knots. It's much more useful than the common overhand knot which is the same knot you tie your shoe with. If you don't want to tie a knot, check out my invention here.
Here are the 5 knots you can tie with this basic know-how:
1. Marlin Spike Hitch
2. Noose Knot
3. Oysterman's Stopper Knot (trefroil)
5. Twin Bowline Bend
This is how to tie them from a marlin spike hitch and what you would use them for...
Step 1: Get a Handle on It.
The Marlin Spike Hitch.
With paracord you can only pull around 80 pounds of tension before it starts to hurt your hand. This is where the marlin spike hitch comes in. It's a great way to put a temporary handle into rope. If you have more then one person pulling you can add several handles to the line. These handles could be sections of pipe, tree branches, or a closed pocket knife.
To form this hitch you form a loop in the free end of the cord. Fold the loop over so that you can pull a bight of the standing end through the loop. Thread your marlin spike through the bight you pulled through and pull both ends tight. Watch the video in the intro for a better demo.
A marlin spike hitch story.
While changing a water heater I attached a hand winch to a ceiling stud. Once the heater was hoisted up off the pedestal I had my wife pull on a rope which was tied around the bottom of the heater. This let me lower the heater to the ground while it was angled away from it's niche. The handle on the rope was a hammer which was marlin spike hitched in.
Step 2: Pull It Together.
The Noose knot.
If the marlin spike hitch spills it turns into a noose knot. This knot will constrict around what it's tied around. It's basically an overhand knot with the standing end threaded through. The only problem is that tension will cause it to unravel. To prevent that you need to add a stopper knot to the free end. Que the oysterman's stopper knot.
A noose knot story.
I wanted to take all our beach gear to the shore in one trip. The cooler, beach chairs, towels, shade structure, sand toys, all of it. I placed a towel on the sand and placed a small rock on each corner. I tied a noose knot around the rock which was covered by the corner of the towel. Kind of like a tootsie pop wrapper. This made an improvised sack. Anything I couldn't carry in my arms went into the sack which I carried on my shoulder.
Step 3: Put a Stop to It.
Oysterman's Stopper Knot.
Once the marlin spike hitch spills you get a noose knot. From there you can easily get a stopper knot. All you have to do is thread the free end through the eye and pull the standing end tight. This gives you a stable trefoil knot. If you look at the first picture the standing end is cut very short. You can see how three even wraps surround the center cord. It increases overall diameter.
An Oysterman's Stopper Knot story.
After moving I had a great big pile of collapsed cardboard boxes. The trash men here in Vegas can be a little feisty so putting all the boxes in the biggest box wasn't a good idea (they once dumped a box out in front of my house, took the box, and left the pile of trash). I smashed an aluminum can and threaded some paracord from a hole in the bottom through the opening. This stopper knot kept the can in place. Every box got threaded with paracord until all the boxes were stacked. When the trash man came he grabbed the paracord handle at the top of the stack and sent them off to recycle.
Step 4: One Good Loop.
According to Wikipedia,
"The bowline is an ancient and simple knot used to form a fixed loop at the end of a rope. It has the virtues of being both easy to tie and untie; most notably, it is easy to untie after being subjected to a load. The bowline is sometimes referred as King of the knots because of its importance. It is one of the four basic maritime knots."
To tie this one, start with the marlin spike hitch. Instead of threading a spike though, thread the free of the line. Let the knot spill when you pull it tight. It will form right into a bowline. Check out the video for a better view.
A Bowline story.
While camping I needed a place for a "trash site". I tied a bowline leaving both protruding ends long enough to tie around a tree. I tied a knot in the corner of a trash bag and slipped that though the bowline. It kept the bag off the ground and made it easy to change out when it was full.
Step 5: Double the Fun.
Twin Bowline Bend.
This type of bowline is not very common but works great. Start out with two marlin spike hitches. Place them on a flat surface so they face the opposite way. Where you would place the spike is where the opposing free ends thread through. When you pull it tight let the both sides spill. This forms the twin bowline bend. Pretty cool right?
A twin bowline bend story.
While working on a project (keep your eyes peeled early summer) I needed a very long section of paracord. The two pieces I had were 100' each. I used this bend to splice them together. It worked great and came apart quick when I was done.