RE: [at-l] Bivy sacks, again.

["Mayer, Jim" <JMayer@crt.xerox.com>]

Nicole,

It sounds like we have similar hiking styles.  I'll just toss in a
couple of things:

> -----Original Message-----
> From: Nicole Markee [mailto:thatgirl@astrogirl.com]
...
> Coosa is a big advocate of ID stuff (I've been reading the 
> Gear Talk site),
> although she uses a Salathe.  Their stuff certainly *looks* 
> good, but the
> Unishelter (the one I'd use if I wanted an ID bivy) weighs in 
> at 2#8 and the
> OR is 1#15 with very similar features...including the long zipper and
> noseeum netting.

Take a close look at the two designs.  I think you'll find that the
designs are radically different.  The Unishelter opens up the side and
across the top, while the OR Advanced Bivy is a "clamshell" design and
opens at ground level around the head.  The Unishelter design allows
nearly your entire torso and head to be open to the air but protected by
netting.  If you have it all zipped up, then double zippers and a couple
of strategically placed pieces of Velcro let you leave air openings at
the side and top... this creates a "high/low" ventilation system that
does a good job of moving warm and humid air out of the bivy.  The OR
bivy looks like it would be comfortable in its open configuration (I
have tried one in a store), but I'd be concerned about condensation over
the head when the "clamshell" is down.  Warm (and humid) air rises, and
in the OR design it has nowhere to go.

The downside of the Unishelter design is, of course, more weight and
more seams.  In addition, the Unishelter also uses a significantly
heavier duty floor (they do not recommend a ground cloth).  They will
make one for you with a lighter floor, but they don't like to because it
isn't as durable.

Anyway, assuming you are well under 6' tall, the weight isn't all that
different.  The standard Unishelter clocks in at about 37 oz. according
to their web page.  With a lighter floor, you might find the weight down
around 34 oz which isn't all that different from the 31 oz of the OR
bivy.

I don't want to slam the OR bivy... I nearly bought one.  I suspect,
though, that you'd be happier using it wide open (with the pole in the
upright position) in conjunction with a tarp.  This isn't a big deal
though, and the tarp lets you keep your gear out of the rain.

> with titanium tent stakes.  My aluminum ones are getting all 
> bent up.  Gosh,

I have not bent a single stake since I switched to the hollow Easton
aluminum tent stakes (about 1/2 oz each).  I really, really, really like
them.

> > The other option that looks like it will work really well 
> for "stealth"
> > camping is to carry just a tarp and a head net to keep the 
> bugs off.  I
> > haven't tried this enough to endorse it, but my experiences 
> so far have
> > been promising.
> 
> I think I'd be more comfortable with a bivy with multiple "settings".
> Besides, I love my down bag, so I really need to stay as dry 
> as possible.

I wouldn't assume that a bivy or tent will keep your bag drier than a
tarp will.  Even in severe rain, a tarp pitched low to the ground will
keep the rain off.  Blowing snow is another story though.  And the
ventilation with a tarp cannot be beat.  With my bivy I usually find
some surface condensation on the bag in the morning.  I'm not talking
about anything that will wet the filling, just a little moisture on the
surface.  Still, our bodies put out quite a bit of moisture during the
night and "waterproof breathable" fabrics only work so well.  That's why
ventilation in a bivy sack is so important.

If you have the time, why not experiment with a tarp?  It is a LOT
cheaper than a bivy!  Both Ray Jardine (PCT Hikers Handbook) and Colin
Fletcher (The Complete Walker III) talk about rigging tarps.

For "motivation" consider the following (disclaimer... never having been
on a thru hike I'm not in a position to make recommendations):

Traditional:

	Tent, stakes, fly, poles, stuffed:  3#10  [your figure, my old
tent was more like 5#]
	Gore-Tex jacket: 1#8 [men's large/tall... I assume yours is
less]

	Total: 5#2oz (6#8oz with my old tent)


Crazed:

	Poncho with extra tie outs sewn in (tall, from Campmoor): 15 oz
	microfiber windbreaker (large/tall again, from LLBean): 7oz
	space blanket ground sheet: 11oz
	Really light cord for the tarp: 1oz
	bug netting: 5oz

	Total: 2#7oz (2#3oz with just a headnet)

Slightly less crazed:

	Add a minimal bivy: +19 oz
	Drop the sportsman's blanket ground sheet: -10oz

	Total: 3lbs (2#11oz without the bug netting)

High tech/low tech (expensive but not crazed):

	Stephenson 2RS tent w/light plastic ground sheet, stakes, and
stuff sack: 3#4 oz
	Coated nylon rain jacket (large/tall): 14 oz

	Total: 4#2 oz

If you want to try a tarp rig, I'd suggest trying it in your back yard
first.  Or maybe take it AND a tent on a trip, so if problems crop up
you have a backup.

-- Jim



* From the Appalachian Trail Mailing List |  http://www.backcountry.net  *

==============================================================================