Okay im trying to make a boat out of plastic bottles.
But need to know .

1) How many 500ML Water bottles does it take to keep 1LB above water?

Also a simple how you figured this out for future needs

Suggestions
For boat are very much appreciated

You need to displace at least one pound of water to keep one pound of something else above water. The density of water is 1 kg/L = 0.5 kg per half-liter. 0.5 kg is more than a pound, so one 500 mL water bottle would theoretically be enough, but that assumes the full 500mL of the bottle is underwater and displacing the water. Plus you have to take into account the fact that if you're using just a single bottle, you're probably not going to be able to easily balance whatever the 1-pound load is since the bottle will just roll and tip over.

Secure two 500mL water bottles together side by side and you should be good to go.

THank you ive been collecting bottles for 8months trying to keep about 500lbs above water me and a friend, (Rounded up to be safe).We are using it on river just as a joke well kinda if it works ill prolly stay with it lol.

Any Suggestions On How to Put all bottles together? what to use as a floor on the boat? What the bottom should be Flat ! triangle 3 triangle?
(

Oh, you're making a full-sized boat? Well crap. I have no idea how you'd secure that many bottles together reliably.

I was thinking

Making just like a pontoon boat with 2 beams of bottles.then filling in the middle with whats left.

It would be long and teadeous but just gluing each botle to the next Formilng the beams then using thwine to tie ever foot or so together.

Glue would be a weak bonding agent for a plastic bottle raft since each bottle would have only one (thin) contact with another bottle. Twine would probably work much better, and if you could make it so the twine passes through the bottles instead of just going around them, that'd probably work better.

But then the bottles would leak

Seal them / 10

Google Images : http://images.travelpod.com/users/chris-roisin/1.1287055116.bottle-boat-covo-i-suva.jpg : I now kinda wana make one...

Thats whats up, can u get me the site that came from so when i get home from work i can look at it better
?