Greetings,

I've been designing a compact personal survival kit and am looking for a better water collection / storage / transportation vessel. Right now I use condoms, but they have their short comings :-).

Recently I discovered oven (roasting) bags. They are not plastic; they are heat resistant nylon. And they are (in my experience) more durable and more compactable than plastic. But the problem with oven bags (as water vessels) is that the height to width ratio is too low. They are often 18x24, and that's not only too big, but not very convenient when you want to tie off the top.

If you measure the circumference of a 1 liter Nalgene bottle, its 11.5 inches. So a tubular bag this same circumference would be 5.75 inches (when flat). Rounding up make the (ideal?) width of 6 inches. Now you want enough bag to tie off the top after filling it with 1.5 liters of water. So I'm guessing that's about 18 inches. Again, just a guess.

It seems like 6 x 18 inches would be a good size. But these dimensions are somewhat reverse engineered to be similar to a 1 liter Nalgene bottle. Is that a good idea?

[can you tell I'm an engineer? :-]

What size would you prefer for these water vessels?

Cheers,
Robert