Gear: August 2009 Archives


August 30, 2009

Behind "what did you eat", "where do you get water" is one of the big questions you get. On the JMT and in the Sierras in general, the answer is "everywhere". I only remember a few stretches of the JMT over 5 miles without some source of water (lake, creek, river, etc.) And for the few stretches where there isn't water, you just need to know in advance and tank up. I carried three water containers: an empty quart-size Gatorade bottle and two 2 liter Platypus canteens, but never carried more than 3 liters of water, even for the dry stretches; if you're moving at 2 miles/hr, then you really only need about 3 liters even for a 5 mile stretch, since you can't absorb more than about 1l/hr.

This is only a partial answer, though, since it's not considered a great idea to drink untreated surface water (though see this article). There are three basic treatment options:

  • Chemical treatment (e.g., iodine, chlorine)
  • Water filters
  • Electronic devices (steripen, miox)

The idea with chemical treatment is simple: you fill your containers, drop the chemicals into them, mix, and wait. Old-style chemical treatment really was terrible: it was slow and left a bad aftertaste. Things have gotten a lot better, though. The best chemica treatment is probably Aquamira, which works in 15 minutes and leaves only a very minimal aftertaste. I've used Aquamira drops, which require mixing from two bottles, but Aquamira also comes in tablet form which I'm informed by friends is more convenient. The big advantage of chemical treatment is that it's ultralight. The disadvantage is that it's slow and can be problematic with marginal water sources: if the water is cloudy you need to prefilter it to remove as much of the particulates as you can. If you are trying to get water out of a shallow stream, you also can have trouble getting your container to actually fill. Finally, it's still annoying to have to wait 15 minutes to drink.

The other traditional alternative is water filters: your typical filter is a pump attached to some sort of filtration element. You drop the input hose in the water and attach the output hose to your bottles. When you pump, the water is forced through the filter and into your bottles. The big advantage of a filter is that it's fast, can work even with very shallow water (since it's a pump), and removes all particulates. Of course, if the water is really dirty, the filter can clog, but the better filters are pretty good about this. Many of them come with prefilters that will remove most of the larger particulates. You can also get two kinds of non-pump filters: small filters that fit over the mouth of a water bottle (this only seems suitable for very limited circumstances) and bag filters (e.g., the ULA Amigo). I've seen the Amigo in action but never tried it myself so can't vouch for it. The big disadvantage of filters is weight: the overall weight of my filter (I use a Katadyn Hiker Pro) is 440g.

The newer alternative is electronic purifiers. These come in two varieties: ultraviolet irradiators (Steripen) and electrolytic (MIOX). [As far as I can tell the MIOX is just making chlorine dioxide, the active ingredient in Aquamira, electrolytically.] Of these two, the Steripen looks better: it's more convenient and seems faster (about 1-2 minutes). I'm not sure I see a huge benefit here: they're both a lot heavier than Aquamira and have a lot of the same drawbacks in terms of marginal water sources that any chemical system has.

I currently use a Katadyn Hiker Pro, and carry Aquamira as backup. The difference between the Hiker and the Hiker Pro is that the Pro has quick connect hose fittings, which is somewhat more convenient. I also bought a Platypus Filter Link so I can pump right into my Platypus containers. This works well, except that there's no vent in the Filter Link, so when you get to the very top of the container, you start to get air back pressure. This seems like it would be fixable by punching an air hole.


August 27, 2009

Some sort of shelter is one of the "big three" heavy backpacking items (the other two are backpack and sleeping bag). Traditionally, of course, this means a tent, but some ultralight backpackers have started to go with some even more lightweight options, such as tarps (see for instance: Tarptent). Tarp construction varies, but at a high level they're single-wall tents with various degrees of full enclosure. A lot of them save weight by using a trekking pole as a tent pole, thus avoiding the need to carry a separate pole. With this technique you can get a single-person shelter for around 20 oz (assuming you're using trekking poles anyway).

I don't use trekking poles myself, and my personal preference is for an ultralight tent: the Big Agnes Fly Creek UL1. The Fly Creek UL1 is a double wall tent: an ultralight mostly mesh bag held up by a single pole and then a separate rain fly. The entire apparatus weighs 1.04 kg (2 lbs, 5 oz) including stuff sacks, stakes, etc. [Big Agnes lists this as 2 lbs, 3 oz, but my scale gives the above number]. It's nominally freestanding, but as a practical matter you at minimum want to stake out the foot of the tent, since there's only a single pole running to the foot the corners tend to flop in otherwise. In addition, if it's cold you need to be careful about how you stake out the rain fly: unless you guy it out especially in the vestibule, you don't get adequate ventilation and there's a lot of condensation inside the tent—I've seen this happen with my Big Agnes Seedhouse SL2 as well. In addition, if you just leave the vestibule slack you get a lot of draft. So, finding a site where you can put the stakes in can be a little tricky. The other minor issue is that the tent only has 38" of headroom so I at least can't sit up straight except in one location and even then I suspect I'm a little bent over. On the other hand, you don't really want to spend that much time in your tent.

If set up properly, the Fly Creek UL1 does a great job of keeping you warm and dry. The next to last day of my JMT trip it started to rain right after I got to Guitar Lake at 3ish and kept going for the next 11 hours or so. I stayed in the tent warm and dry pretty much the whole time and slept well. The two guys next to me were in tarp tents (not sure which model) and complained that they had a lot of wind and rain intrusion (I think due to the requirement to keep some openings for ventilation) and that they were extremely cold and wet and didn't really sleep at all. Seems like that difference was worth a few ounces and I saw other people ogling my Big Agnes.

I should mention that on about day 8 (probably the 9th day I'd used the tent) I went to stow it in the stuff sack and the top 3-4" of the stuff sack tore almost completely off (there's a seam running down one side and that didn't tear). This doesn't affect the functionality of the tent—it's just the stuff sack—but it's a minor inconvenience. I've contacted BA and they're sending me a new stuff sack.