View Full Version : Food Volume

charlottebronte

04-21-2004, 20:34

We've heard of the weight-per-day rule of thumb for food consumed on the trail (either 1 1/2 or 2 lb's), but how about the volume? How many cubic inches should I plan on packing for a 5 day food drop at 2 lbs per day?

SGT Rock

04-21-2004, 21:15

I have a 10"x21" food bag that would just about be full for 5 days of food, but not quite totally full. 10x21x3.14 would be 659 cubic inches if I figured that correctly.

I have a 10"x21" food bag that would just about be full for 5 days of food, but not quite totally full. 10x21x3.14 would be 659 cubic inches if I figured that correctly.

Happy to see you back, Sarge. By the way, which is worse: a Baghdad summer or Louisiana summer (assuming no air conditioning)?

A 10 inch diameter, 21 inch long bag would have ~ 1650 cu in. pi*r²*l.

Moon Monster

04-21-2004, 22:49

No, Sgt Rock's right at 659 cu. in. Volume is pi*d*l. Sqauring the radius and multiplying gives you surface area.

When I was consuming maximum calories on my thru-hike, my food bag was often stuffed full for 4-5 days and I had bagels and a jar of peanut butter stuffed in the pack elsewhere. My bag is 9x15, which is 424 cu. in. plus another couple hundred cu. in. for the jar and bagels.

Incorrect formula here; see posts below

SGT Rock

04-21-2004, 22:59

Baghdad summers seem worse, absolutly no shade at all and flak vests may make it seem worse than it really was, but 150 is going to suck no matter what.

No, Sgt Rock's right at 659 cu. in. Volume is pi*d*l. Sqauring the radius and multiplying gives you surface area.

When I was consuming maximum calories on my thru-hike, my food bag was often stuffed full for 4-5 days and I had bagels and a jar of peanut butter stuffed in the pack elsewhere. My bag is 9x15, which is 424 cu. in. plus another couple hundred cu. in. for the jar and bagels.

Not so. Pi is a constant. To get cubic inches you multiply in. x in. x in. Multiplying the surface area of a 10 inch circle pi x r² times the length of the bag will give the volume of a cylinder. Your calculation is square inches of something. If it were a 10 inch by 10 inch (square ends) by 21 inch container then the volume would be 2100 cu in. You could find the volume of an inscribed circular sac by multiplying this by 3.1/4. Multiply by .75 to estimate or for government work.

Moon Monster

04-22-2004, 09:29

Aha, you are correct Groucho. Upon re-doing the calculations, Sgt Rock's bag is 1650 cu.in. and my food bag is 954 cu.in. which makes since as it appears to fill 1/4 to 1/3 of my 3200 cu.in. pack when full. Altogether, I may max out at 12-1300 cu.in. of food (and packaging) for 5 days.

SGT Rock

04-22-2004, 09:35

OK, I'll agree with that. Like I said, my food bag is not all the way full, and inside it usually goes my kitchen stuff as well, so 1200-1300 ci of pack space may be right. I haven't done geometry in about 20 years so insead of Pi*r2*l I was doing Pi*2r*l, so instead of squaring the radus, I was doubling it which was my error.

We've heard of the weight-per-day rule of thumb for food consumed on the trail (either 1 1/2 or 2 lb's), but how about the volume? How many cubic inches should I plan on packing for a 5 day food drop at 2 lbs per day?

Well, I've never figured out food based on volume. But I know that I can put about 5 to 6 days of food in an 8 x 18 stuff sack.

Footslogger

04-26-2004, 10:41

Actual "volume" of food carried depends a lot on your choice of foods. Once my diet somewhat leveled off on the trail last year I was able to get 4 days worth of food in a 7" x 15" silnylon stuff sack. That sack, when full, averaged around 9 pounds.

Like I said ...volume changes based on your food selections and the degree to which you "repackage" your foods before stuffing them in your food bag.

Hope that helps ...

'Slogger

OK, I'll agree with that. Like I said, my food bag is not all the way full, and inside it usually goes my kitchen stuff as well, so 1200-1300 ci of pack space may be right. I haven't done geometry in about 20 years so insead of Pi*r2*l I was doing Pi*2r*l, so instead of squaring the radus, I was doubling it which was my error.

I did worse a couple of weeks ago; cursed myself all the way back to the store.

Just didn't want charlottebrontė to buy by cubic inches and end up with too small a bag.

Actually, when doing the calculation you could subtract the radius of the bag from the length (because of the drawstring at top) and get a better approximation.