A rope bridge is the simplest and oldest kind of bridge. It can be as basic as a single rope that people hang from to pull themselves across. Other kinds of rope bridges have one rope to stand on and one higher up to hold to pull yourself across, or a rope to walk across and a trestle on either side to hold on to.
Laying Out the Ropes
Find an area with two trees about 60 feet apart; these will be the anchors for the bridge. Cut two lengths of 2-by-4-inch lumber to 10 feet and cross them to make an X, with the cross three feet down from the top. Lash them together with 1/4-inch rope. At equal distances along the bottom part, cut and place a 3-foot, a 4 1/2-foot and a 6-foot lengths of lumber so they resemble rungs on a ladder. Tie them in place with nylon rope; this is the first spar. Repeat the process with the remaining boards to make a second spar.
Cut the 1/2-inch diameter rope to make two lengths, each 150 feet long. Tie the 1-inch diameter rope and both of the 1/2-inch diameter ropes to one of the trees. Use a round turn two half hitch knot to be sure the ropes are secure. Lay out the ropes to head toward the other tree, with the largest rope in the middle.
Tie the block and tackle to the second tree and lay it out toward the ropes from the first tree. Tie a bowline in the thick rope where it reaches the block and tackle, then attach that rope and the block.
Building the Bridge
Position the first spar under the ropes, about 10 feet from the first tree. Tie the two smaller ropes to the top of the spar using clove hitch knots. Raise the spar until it’s at an angle of 45 degrees, pointing away from the tree.
Place the second spar about 30 feet from the first, with its top pointing toward the second tree. Lay the ropes on top and attach the two smaller ropes to the top of the spar with clove hitch knots. Raise the spar so it leans at 45 degrees, then raise the handrails you’ve created using the ropes are parallel to each other. Tie the ends of the handrail ropes around the second tree.
Position the thickest rope, which will be the foot rope, so it crosses both spars at the top of the X. Tighten this rope with the block and tackle until it’s taut. Adjust the handrails with an extra knot if they sag too much.
Cut the 1/4 inch rope into 36-inch lengths. Tie the end of one piece to one handrail with a round turn two half hitch knot, then to the foot rope and up to finish by tying to the other handrail. This makes one stringer; add extra stringers every three feet along the span of the rope bridge.
Don't build the rope bridge over streams or dips in the ground, as children can fall and suffer injuries.