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!