I have been thinking a lot about BOB's lately. Is there a way to determine the amount of weight each family member can carry in their BOB. I see a lot of places mention you should carry water in your bag but the amounts they recommend don't make sense to me. If you carried that much water, most of your bags capacity would be taken up with water... that makes no sense. It seems to me it would be better to carry a small emergency water bottle and know how to find other sources of water to drink. Could somebody tell me what sort of materials are used to make good backpacks. I baught an expensive tactical backpack, and it lasted a day... the material was so rigid it just cracked and split. I decided I could make much better, so i'm going to do it myself.