Cut the material in half to obtain two 60-inch by 90-inch pieces, or lay two twin wool blankets together to obtain a doubled piece of wool material.
Cut 1-inch wide strips, 4 inches deep into the material, starting on the long side of the doubled material until you reach 4 inches from the bottom corner of the material.
Turn the doubled material. Starting 4 inches from the corner, cut 1-inch wide by 4-inch deep strips across the bottom side of the material. Note that a 4-inch by 4-inch square of material will be cut from the doubled material in the corner.
Turn the material again and continue to cut strips up the opposite long side, starting 4 inches from the bottom corner. The last cut should be 1 inch from the top of the material opposite the first cut made.
Tie a square knot in each strip using one piece from the top material and one from the bottom material. The result will be a double material wool blanket with one end that can be opened.
For a heavier blanket, change the weight of the wool material. Wool material is manufactured in a variety of weights from light "tropical" to heavy "coat" weight. One can adjust the warmth desired by changing the weight of the material.
You can also add another layer of material. Place another piece of fabric inside the blanket by inserting it into the open end of the blanket. The triple warmth of thinner wool material will retain body heat better than two layers.
Another option is to make the layers from different types of wool materials. Chenille and wool flannel have loft, creating a dead-air space for body warmth. Tweed is a heavier wool fabric. Placing the softer, lofty material closest to the body with the heavier material on the exposed side will help retain body heat more efficiently.
Change the type of wool material. Wool is commonly made from the fleece of sheep. Wool fabric can also be manufactured from goat or alpaca fleece, and each has a different insulating property.
For extra warmth, climb inside the blanket instead of wrapping it around you. As we sleep we often toss and turn, unwrapping the blanket. Climbing inside the blanket is much like using a sleeping bag.
Add a bottom pad of heavy wool felt or duck, a tightly woven fabric, to the hammock before you hop in. This pad will block the wind from the underside of the hammock, which will help retain the warmth of your body.
Slip a warm rock or two inside your blanket to get the material cozy before you climb inside. Placing rocks near a campfire or stove will heat them up. Once the blanket is warm, the rocks may be removed or kicked to the foot of the blanket. Place a hot water bottle inside if the idea of rocks in your hammock is not appealing. Hot water bottles have been around for decades and are a great way to warm not only your hammock blanket but your clothes and body. Simply fill the bottle with hot water, replace the lid, and tuck it beside you. To rapidly warm your body, place the hot water bottle on your chest. This helps increase your core temperature.
Wear more clothes. While no one wants to take a nap in a hammock looking like a polar bear, a pair of thermals or a down vest keeps goose-bumps away. Put on socks, gloves and a hat. The human body quickly loses heat through the head and extremities. Keeping these areas covered helps retain warmth.
Bring a friend. Even Fido or Fluffy produces some added body heat, but watch out for unexpected flips that can occur if they make sudden exit.
