I also wrote an article, Tungstite the Kayak: Sink or Swim? for my school magazine. Read it if you're interested in the backstory of making this Kayak.
Thank you hyroc346 for inspiration, fellow engineering club members, and coach George for letting us use the pool.
Step 1: Materials
For the boat
12m 1" PVC pipe
4m .5" PVC pipe
1×.5m Wooden plank
2 rolls Duct tape
2 foam blocks (size that fits the bottom of your kayak)
2 1×1' foam pad
1 chair (salvage it from somewhere)
For outriggers (optional)
12m 1×2" wood
4 Water dispenser bottles
8 Drywall screws
For the Paddle
2m 1" aluminum pipe
40×40cm Acrylic sheet
4 nuts, 4 bolts, 4 washers (any size will suffice)
Step 2: PVC Skeleton
Then, cut the 0.5" PVC pipe into: 2×70cm, 2×60cm, 4×35cm, 2×40cm. These segments will become the supporting frame?. Now, take each of the supporting frame and make "legs" on each side. Look at the pictures to see how to make them.
Back to the structural frame. Making sure that the cuts face each other, connect the two 2.5m segments at two ends using duct tape. It is important that you tape it tightly. Otherwise, the boat may break and sink. You can apply epoxy glue to the joining surface if you have the glue.
Then, combine top and bottom structural frames by drilling holes through each end and forcing in a copper rod.
Next up: add supporting frame segments. Since it's hard to describe it, I scanned a diagram showing how to do this.
The credit for this frame idea goes to hydroc346.
Step 3: Attach Chair and Foam
First, take a wooden plank and drill several holes, then zip-tie it to the bottom supporting frames. Drill some holes through the chair and the plank, then use zip-tie to secure the chair into place.
You need some material to fill up the vacant space under the wooden plank, so I added some blue foam and simply hot-glued it in place.
Step 4: Wrap Skeleton With Tarp
Tape the front and the back tips, then zip-tie the tarp onto the frame. (if your tarp has loopholes). If it doesn't have rings, you can either simply tape it onto the frame or make holes using a hole puncher.
Flatten out the tarp as much as possible to prevent it from looking too much like a garbage can.
After you're done wrapping the kayak with tarp, add some foam on the bottom of the tarp so that the bottom doesn't get scratched up.
Step 5: Make Paddle
Drill holes on the acrylic, making sure that the holes are spaced as they are on the aluminum pipe. Attach the acrylic to the pipe using nuts, bolts, and washers. Don't tighten it too much, as it may crack the acrylic.
Step 6: Attach Outriggers
Although the boat becomes very stable, there are some trade-offs. It's harder to paddle the kayak as you have little space. However, you can utilize the outriggers as storage area - rope, fishing line, etc. I'm also thinking of using velcro to make detachable flashlight, compass. etc.
Step 7: Test It Out!
I first tested it out without the outriggers - it was rideable, but was somewhat unstable and I had to spend a lot of energy trying to balance.
With the outriggers, it was much more stable - I could stand on the kayak and not flip the kayak. Don't lean backwards too much though; water might get in through the back. One suggestion I have for you is have the chair placed more in the front, moving the center of gravity to the front so that the kayak won't be tilted so much.
If you also make one, post a picture of yours in the comments!