In many tropical locations where there are bamboo forests, rafts made of this giant member of the grass family are a traditional mode of river travel. Bamboo is strong, light, grows very quickly, and for rafts, it is ideal as the segments inside it are water tight. Bamboo rafts can be built quickly and are predictably stable as long as the river is not too choppy.
Cut ten 10-foot-long lengths of 4- to 6-inch thick dry bamboo. The best time for harvesting bamboo is in winter when the stalks are at their driest. In spring, the segments inside the bamboo fill with sap, making them heavy and less buoyant.
Lay the ten lengths side by side on level ground to form the raft. Cut three additional lengths of bamboo to use as cross braces. These should be as long as the raft is wide. Lay one cross brace at either end of the raft, and one in the middle.
Lash the cross braces to each of the 10 raft poles individually with the twine to guard against breakage. Tie them as tight as possible and finish with square lashing knots.
Place the raft in the river with the cross braces facing upward. Sit just to the rear of the middle and control the raft using a long bamboo pole. The idea with bamboo rafts is to flow with the river, but the long bamboo pole can be used to push the raft along if the depth of the river allows.
Longer and wider rafts are more stable.
Do not attempt to take a homemade raft into deep water far from shore. Always wear a personal flotation device when using your raft.