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.

**Signing Up**

## Step 1: How Many Bottles?

**Section 1**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.

**Section 2**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!

and also can we use it in flash floods??thanks!:))

_{(get it, bear-bare? hehe)}Also, if the bottle collapses slightly in water due to the weight of the water pressing against the outside, there will be a little less volume and thus it will support a little less weight.

A liter is a little bigger than a quart, a gallon of water weighs about 8 lbs, so a quart weighs about 2 lbs, so guesstimating that 2 liters will support about 4 lbs won't be too far off.

You could also simply fill the 2 liter container with water and weigh it--like I said, it will support about the weight of water it contains. (If you want to be precise, you could subtract the weight of the air the bottle will hold when we call it empty, but that is negligible. You will have to account for the slight collapse of the bottle underwater (as mentioned above), so if you weigh the bottle full, figure it will support a little less than what you weigh.

Of course, you'd want to figure on using more bottles than this caculation indicates, to account for all kinds of things, including the potential of bottles springing leaks due to collisions, abrasion, or whatever.

Hope this helps!

You can get a lot of bottles at small businesses that you´re familiar with, like restaurants. Once I went to a small casino to get bottles (not familiar with) and got like four BIG and FULL black bags of 2l bottles.

30 lbs = 13.6 Kg

So to support 13.6 Kg, you'd need 13.6 Liters of air. That's 27.2 average water bottles. Remember you also have to account for the weight of the plastic and that the 27.2 number is only to equalize the weight. You'll want to use extra if you really want it to act like a boat.