Comfort
Load bearing capability (how much weight does it (you) have to carry)
Cost
Color
Ruggedness
Versatility
Before we go further, let's discuss the rule of 3 (or 4 depending on who's talking)
You can live:
About three minutes without air
About three hours without shelter (in an extreme cold climate)
About three days without water
About three weeks without food
Allow me to digress a moment. I would also like to add security. Without security, you may live only about 3 seconds.
So, what are the priorities?
1. Security - first and foremost, always, immediately secure you area!
2. Air - probably not an issue here unless someone is choking you.
3. Shelter, probably not as critical an issue, unless it is snowing or worse yet, you are in a freezing rain
4. Water next to security will likely be your most urgent concern.
5. Food, although listed last, be sure you have plenty in your pack.
Remember, #1or #3 are no more important than #4 or #5. All are equally important; you can not live without each one of them. I have only prioritized them in the order death normally occurs without them.
Let's talk about each of these priorities individually.
Security: Safety and protection from predators, either two legged or four. Safety also from natural disasters such as wildfire, storms, earthquakes, etc. Consider the tools needed for the job.
Shelter: Since we are speaking of this in the context of the Survival Rucksack, in my opinion, your shelter needs to be the kind carried on your back. Remember the tortoise? So what to carry?
My first choice is the Bivy Sack. It should be made out of Gore Tex or some other high quality breathable material. The bivy sack (or bag) is nothing but a large envelope of breathable, waterproof material that zips up with you, your sleeping bag and hopefully some room left for your gear. I have slept in very rainy weather inside a good bivy, all the while staying warm and dry. The U.S. Military has been using them for some time now and they are available on the surplus market in new and used excellent condition.
Second choice, I would consider a good one man tent; a rugged one that is light weight. The problem here is that these can get quite pricey and are still heavier than a bivy or lightweight nylon tarp shelter.
My third choice shelter is an oversized poncho like tarp at least 7' X 9' in a drab color. I prefer a rip stop nylon material with several grommets around the edges and loops for suspending it from a tree. There is one available from some of the outdoor catalog companies called the S.A.S Shelter. Be sure to require that it is the authentic item. This is a reasonably priced item and it gives you a better field of view of your surrounding area than a tent.
Water: Real simple. To carry only 1 quart of water is folly. You need to carry an absolute minimum of 2 quarts; but a more realistic quantity is up to 4 quarts. I repeat, 2 quarts of water is the absolute minimum that should be carried by an adult. Two additional 1 quart canteens or a lightweight 2 quart jungle canteen can be carried empty when you are in an area that has ample water and filled as needed in drier areas. Water rehydration bladders are all the rage these days and they do work well, but they are a bit fragile. I would not rely on them solely as they are easy to puncture. Also keep in mind it is very easy for an adult to go through 4 quarts of water a day when carrying a rucksack in warm weather.
Food: Food is your final priority, but it is as important as any of the others; you can't live without it, and it is the one hardest to replace. I know all the Rambo's out there are laughing now, but trust me, food is harder to acquire than you might think. “ I'll just kill me a deer or a bar”, O.K., but see how far Bambi goes when everyone out there has the same idea. I have hunted the High Sierras on several occasions and sometimes the only thing I saw were Chipmunks. Maybe I'm just a poor hunter.
I have taught survival in the Army and I have rarely seen anyone put on weight on one of these outings unless they had smuggled in a gas mask carrier full of Hershey bars. The best answer I know of is to carry as much high calorie, high protein, light weight food as you can manage. Of course, if you had a stash under a rock someplace that would be great, but then you would not need your rucksack would you. Always remember Murphy,s Law. “Anything that can go wrong will go wrong”. On your back is where you want your food.
