rule of thumb
phrase of rule
plural noun: rules of thumb
- 1.a broadly accurate guide or principle, based on experience or practice rather than theory.
Recently (as in yesterday!) I received an email from a friend asking how long a canister for an MSR Pocket Rocket type stove will last in the backcountry.
I quickly typed an answer. One I’ve given before.
My friend astutely noted that it seems like I’ve done this once or twice before.
Indeed I have. 😉
In the time I’ve backpacked, I’ve learned to develop “rules of thumb” for common questions or scenarios.
As with all rules of thumb, they are broad overviews. Something meant to give some basic information for common questions.
What many of the exact number-minded backpackers fail to realize is that when a simple question is asked, people are looking for a rough idea that is reasonably accurate.
The person does not want to know the air speed velocity of a swallow if one is near by or how many minutes of simmering a person could achieve on their back deck (Who is timing in their boiling of water in the backcountry? And if you are timing how many minutes you get out of a canister while in the backcountry, I really don’t want to hear about it) and so on.
Instead, here are some common questions and rules of thumb to go with them. I don’t claim they are scientifically accurate. They are just good enough for most people who want some real world advice and more likely to get it using gear than by setting up gear in a backyard for testing. 😉
- How long does a fuel canister last for when used with an MSR Pocket Rocket (or similar) stove?
There are many variables of course. How cold is it? Is there a lot of wind? Do you have the stove on full blast or a slight simmer? For most people, though in the common variations of three-season backpacking conditions with a medium to low setting on the stove, there is an answer I find pretty consistent: In general a 4oz fuel canister will last about 10 boils.
I think of terms of boils as that is how people generally “cook” on backpacking trips. Obviously, if someone is sautéing veggies, frying fish or what-have-you, more fuel is being used.
So, to answer the question, assuming a typical backpacker meal is three cups of heated water (two cups for the meal, one for the hot drink), a 4oz fuel canister will last ~5 days if doing two meals a day. Adjust the math if doing one hot meal a day, no hot drinks, cooking for two or using a larger canister. Obviously, cold weather conditions are another ball of wax. But most people asking this question aren’t planning on winter backpacking.
Exact? No. Realistic for most? Yes.
- How long will it take to hike Cool Trail up Awesome Mountain?
Another question with many variables that is asked often. How long will take to hike a trail?
A seasoned trail runner will blast up the mountain. A person who hikes only a long trail once every two years and does not do anything in-between may not even make it up the mountain. Altitude, the condition of the route, etc. all factor in, too.
But for a person who is reasonably active, carrying average pack weight and is used to the elevation, the old formula from many guidebooks is still pretty good for any maintained single track mountain or even rolling hills trail: Two miles per hour with an additional half-hour for each 1000′ gained.
In the real world, if you are hiking 14 miles with 4000′ gain, figure nine hours total without breaks for Jane Average hiker. Simple. ‘Eh? A more experienced and fit hiker can probably go a little bit faster, naturally. But for the person just starting out hiking, the above rule of thumb works well.
- How much water should I carry?
Until a person dials in their backpacking, a conservative rule of thumb is to take One liter per five miles hiked between water sources. Dry camping? Carrying an extra 3 liters for camping seems to work well (1.5 liters for dinner, drinking at the meal and at night. 1.5 liters for breakfast and to get you going in the morning to the next water source. Naturally take more for dry camping if the water source is further away the next day. ) Of course, if you cook dinner at a water source, then hike on to a dry camping spot to sleep, less water is needed for camping. But that’s another discussion.
- How big of a pack do I need?
There is a happy medium between the minimalist sub-1lb packs and the gargantuan 100-liter monsters many people still think they need for a weekend on a well-maintained trail.
If you pack what you need and perhaps a few luxury items, an ~60 liter +/- pack is a nice happy medium for most people and their needs. Small enough for weekend jaunts, large enough for shoulder season trips and multi-days. Usually not overly heavy and has enough support, unlike more minimalist packs. Popular packs in this category include the ULA Circuit (see my review of its big brother the ULA Catalyst.), the Osprey Exos 58 , the Granite Gear VC 60 and the Gregory Zulu among others.
- How big of a tent should I get?
A one-person tent is just big enough for a person and little-to-no gear usually.
A two-person tent is spacious for one but tight for two.…but perfect for one person and a dog.
A three-person tent is about right for two grown adults.
A rule of thumb? For the types of tents sold at REI, figure out the number of people in the tent needed and add capacity for one more person. In other words, get a three-person tent if packing for two!
Lightweight tent manufacturers such as Six Moon Designs or Tarptent tend to have more spacious designs. But there are more variations in sizes between shelters from these companies. Some of the designs are very minimalist. Others are spacious even for two.
- How thick of a sleeping pad do I need for backpacking?
Don’t think about thickness, think about R-Value and the type of conditions you are seeing. The R-Value is going to be more pertinent than the thickness of the pad.
Not sure what R-Value means? Read something I wrote earlier and come back. Go ahead. I’ll wait.
Now that you know what R-Value means, here some rules of thumb for the minimum R-Value you need. Obviously, colder sleepers may wish for a higher R-Value in their pads. A thicker pad is more comfortable obviously.
Night time lows of 35 at most? An R-Value of 1.5 to 2.0. Blue foam pad or similar. People who use the minimalist pads should know how to pick their camp spots to maximize the warmth and utility of their gear.
Shoulder season backpacking where the temps dip to about 25F and/or want an all-purpose pad in general? Get a pad with an R-Value of 2.5 – 3.0 The Z-Lite or Ridge Rest are two classics in this category that are light and not terribly expensive. Something such as the newer NeoAir is considered light and more comfortable by many if expensive. This category is the sweet spot for most and fits many different conditions seen in the backcountry.
Deeper shoulder season? A pad with an R-Value of 3.0 – 4.0 is usually suggested. I personally consider deeper shoulder season to be when it dips to around 15F. Late September or early October in the Colorado high country usually. I make do with a Z-Lite, but something with a better R-Value is preferred by many. A less expensive solution? Combine it with a thinner and light foam pad to up the R-Value. A cheap way to increase the versatility of your sleeping pad system.
Winter? 5.0+ I combine my Z-Lite, a Neo Air and a sun shield together for a wonderful light, versatile and reasonably light sleeping system. I prefer this system to one big, and puncture prone, sleeping pad.
- How long will my mobile device last between charges in the backcountry?
More and more people are using their mobile devices as part of their backpacking toolkit. Smart devices take decent to very good photos, are useful for navigation and have many field appropriate apps.
But how long will this golly-gee-whiz technology last in the field? It all depends.
However, if you keep the phone in airplane mode (Sorry, Instagramming your selfies you take on your EPIC JOURNEY OF SELF will be far more difficult), have the screen on the dimmer side, take the occasional GPS reading and rely mainly on your map and compass skills, take snaps and not videos and perhaps do some light reading at night, a mobile device will last about five days between charges.
If you are a heavy GPS or app user, tracking yourself for making maps, filming videos or perhaps trying to Instagram your #liveauthentically photos from a one-bar 3G connection, you’ll need an Anker box or similar for more frequent mobile device use.
Here are a few quick tips and rules of thumb I’ve noticed from over the years. Hope this Q&A grab bag was helpful.