The PVC pipe raft is much faster in the water than your typical Barrel Raft.
This basic raft can be built out of scrap lumber, but finding pvc pipes large enough can be tricky. The above raft was originally conceived with four 6" x 12' PVC drain pipes. The four pipes did not provide enough flotation, so 2 additional 4" x 10' pipes were added. (But as you can see in the photo on the left we still rode low with 3 people on board)
>> my barrel raft uses a similar design to the PVC craft
The key to making this work is having enough buoyancy from the PVC, the pipe is deceptively heavy. I would recommend obtaining pipes of a 10" or greater diameter.
The pipes are attached by drilling through each pipe near the end, and then securing it with large bolts to the wooden frame. Seal the holes with caulk and then plug the ends with homemade wooden discs. [if you can obtain pvc caps, these are much better.]
In order to obtain the true speed potential of this craft, you will need to set up an oarlock system as seen in the photo above on the right.
Since this design is extremely stable, you can easily rig a sail and even a plank!