The entire process of developing Project rRaft was documented at rRaft.blogspot.com.
WARNING: General safety rules, as well as some state laws, dictate that you should have at least one PFD for each passenger of a boat. In the pictures, we are not wearing any, but also realize we did not row very far off shore. Go boating at your own risk. Also, be careful with any tools and such that you use.
Step 1: How Many Bottles?
I wanted my raft to support myself, and a friend if the opportunity arises. I weight 170 lbs, and i'm factoring for a friend who weighs the same. That's 340 pounds. Add in the weight of the boat plus extra buoyancy to keep us above water, and we're at 400-500 pounds of needed buoyancy.
- The average water bottle contains .5 Liters of water.
"A body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid."
Thanks to scientific measurements, one liter of water supports one kilogram of weight.
If each water bottles supports half a kilogram, which is about one pound, than you need just as many bottles as pounds you wish to support. I used exactly 450 bottles in my raft.
First, decide how many pounds of cargo your raft should support, that number is roughly how many .5 L bottles you will need.
Easy as that!
Step 2: Gathering Bottles
- Carry a bag with you everywhere for collecting bottles - I would get 20-25 bottles a day this way
- Dumpster dive on recycling day
- If you or friends play sports, put a collection box where you practice
- Put a collection box in teacher work-rooms (if you're in school) or break-rooms (if you have a job)
- Get friends to collect at their houses, too -- One friend of mine brought me a garbage bag full every week or so
Step 3: Bottle Processing
First, all the bottles are dumped onto the floor, and I sit down and cut off each and every label. This needs to be done so that they don't come off in the water...pollution is bad. Once the label is off, each bottle's contents is emptied into a Gatorade bottle (One is picked out from the pile) because most water bottles still have a bit of water left in them, and every bit of buoyancy counts! Gatorade is the bottle of choice because they have large mouths, making them easy targets (and spill resistant) along with higher volume capacities than most water bottles. Bottles from juice, soda, or sports drinks need to be rinsed out, so they are separated as they go through initial processing.
After the entire cache of labeled bottles is exhausted, the non-water bottles are taken to the bathroom and washed out. If any water bottles were partially full, that water is used before sink water. The bottles are then taken back to be assimilated into the general bottle population.
Now it's time for the counting! Kitchen garbage bags are retrieved, and 50 bottles are deposited into each one. Full bags are thrown into the vacant tree house out back, and the surplus bottles (< 50) are left in a laundry hamper, eagerly awaiting the next bagging day. Lastly, the final tally of bottles is recorded.
Step 4: The Plan
The basic concept was to have two pontoons with a platform over top. Fishing nets would have been optimal for holding all the bottles together, but I had no source, so I used garden mesh and zip ties to hold them together. I also ended up making a third pontoon to support the necessary weight.. The frame is made from 1/2" electrical conduit connected with threaded 1/2" PVC corners (they're cheaper) and connected with liquid nails. The platform is painted plywood.
Step 5: Pontoons
Each of the main cylinders was able to hold 162 bottles. Simply fill it with bottles and zip tie it shut.
Rinse and repeat.
My third pontoon was a last minute thing, and since it was going in the middle, I decided to make it pointy, sacrificing some volume, hoping it would look good. In order to get an even 450 bottles, the third pontoon had 126 bottles.
These are pretty simple, but somewhat time consuming.
Step 6: The Frame
2 - 10' length of 1/2" electrical conduit
4 - 1/2" threaded PVC corner
1 - Tube of Liquid Nails
1 - Rubber mallet
Home Depot decided that they wouldn't cut my conduit for me, so I went to Lowes, which happens to be right across the street, less busy, and a whole lot nicer. The guy at Lowes (go to the plumbing department, that's where they'll cut it) cut each piece into 6' and 4' for me. Follow the directions on the liquid nails to assemble a rectangle. The rubber mallet is to make sure the pipe gets into the elbows nice and tight.
Step 7: The Platform
I painted a piece of plywood with some left over paint we had, then sanded and painted again. That's about it for the platform..what can I say? Plywood is simple.
Step 8: Attach It All
Attaching the pontoons to the frame is a lot more complicated, as they need to be removable. You'll need a decent amount of rope, four hose clamps and four eye bolts to attach the three of them.
First, tie a length of rope around the pontoon about a third of the way in from the front and back of the outer pontoons. To prevent sliding, weave it in and out all the way around. It doesn't have to be every other square, but do it enough to prevent breakage. I tied to ends of the rope together using a Sheet Bend knot. Use these pieces of rope to attach the pontoons to the frame with a hose clamp at each one.
Next, drill and screw in four eye bolts, two on each side of the third pontoon. Use a length of rope through the two loops of rope on the other pontoons. Weave the rope in and out of the middle pontoon, making sure to go through the eye bolt when you reach them. This serves multiple purposes, tying to the outer pontoons keeps them in place. Two attachments points would allow them to flow outwards, putting the platform at water lever. If you tie the rope tight (I used reef knots here) the middle one will stay in place, and the eye bolts will keep it raised.
If you did everything right, the only knots you'll have to undo are reef knots. The loops around the outer pontoons stay in place permanently, while the loops that hold the middle pontoon in place will be removed for transportation. To remove the outer pontoons, just undo the hose clamps.
Step 9: First Test
By myself, I could easily stand on it and rock back and forth. It's extremely stable. I grabbed the pool broom to push myself around, it doesn't have much friction, hence the look of concentration on my face in the photo. With two people, it's still stable, but I wasn't about to try standing up.
Step 10: Finishing Touches
- PVC bumper on the back, to make getting on from the water more pleasant
Painted name plate attached with eye bolts and rope- It would hang in the water
- Rope loop to assist with getting on from the water
- Eye hook for docking
Once it's split, slide the bumper slowly onto the back of the raft's platform, then screw in on. Mine is about 2.5-3 feet long.
Step 11: Paddles
I drilled two 1/2" holes in the paddle so that it can be tied to the boat.
Step 12: Maiden Voyage
I brought with an electric screw driver with me, and using it, I was able to assemble the entire raft in about five minutes at the lake very easily. I took trips both with someone else, and by myself. I weigh around 170 pounds, and so did one of my passengers. We rode pretty close to the water, but it was definitely still stable and buoyant. As you can see below, it's stable enough for both of us to stand up at the same time. With a (much smaller) girl, we were a few inches above the water, and by myself, it was perfect.
I haven't gotten a chance to use my home made paddles outside of the pool, as they hadn't been sealed by the time we went on the lake.
The rope-loop-step and plastic bumper worked amazingly for getting back onto the raft, and not a moment too quickly - the water was freezing! My lightweight passenger did get slightly wet when I was getting back on, however.
Overall, rRaft was a huge success, and a project that i'll continue to use when the summer comes around. I encourage anyone interested to embark upon a journey such as mine. Enjoy!
The video isn't great, but you can still see that it works.