To begin, inflate the heavy-duty truck inner tubes you have obtained. These are just the thing to use for a raft, as they are durable, buoyant, and do not puncture easily, so do not substitute them with something like children’s plastic inner tube toys. You will need at least four of these to build a stable raft, but you can use more if you wish, especially if you are looking to build a large raft.
Once all the inner tubes have been inflated, start building the frame for your raft. Stack two long poles to form either side of the raft – lay these out horizontally, parallel to each other. Then, on top of and across these two, stack four shorter poles vertically, to complete the basic square frame. Lash all these poles together with strong twine, to secure the frame.
Now, start building the floor for the raft – you will need to use thinner bamboo poles for this purpose. Line these up evenly across the top of your basic frame, to form a comfortable surface to sit and stand on – do not crowd too many poles together, but you will also need to make sure you don’t leave any significant gaps in the surface, where your foot might slip in. Once you’ve laid the floor out as you wish, lash it all together with twine, and secure it fully.
Finally, you will need to attach the inflated inner tubes to the bottom of your raft, so that it can float. Once again, use twine to secure these to the bottom of the raft, and make sure the nozzles are all pointing upwards, so you can easily re-inflate them whenever you choose. Lash the tire tubes in each corner of the raft so that they all support the weight evenly. Once this is done, your raft is ready for the water.