In an effort to lighten my pack, I've been exploring a shelter switch from a tarptent moment (which I currently own) to a tarp + bivy setup. Also considering tarp + MLD serenity net tent.
When I compare actual weights, I'm not blown away by the savings, especially when considering the functionality I'd be giving up. This is especially true when you factor in the weight of a full stake set, as described in Ryan Jordan's "tarping for inclement weather" article.
Here's the numbers I've come up with based on actual measured weights. In short, under the most optimistic scenario (no stakes, no guylines), I'm saving 13 oz with a tarp/bivy combo. Factor in stakes and that drops to 8 oz, and swap the serenity shelter instead of bivy (as I might do when there's heavy bug pressure), and it's even less. My weights don't include guylines for the tarp, so add another couple ounces or whatever...
I also included a cost/oz calculation, which is not super inspiring either...
So, what am I missing here? Is the lesson "don't bring stakes?" And if so, at what cost in terms of functionality and hassle? Or, do I just need to accept the incremental nature of weight savings?
Sorry the formatting is funny, I tried to fix it to no avail.
Weight (oz) Cost
Bivy 7.125 $85.00
Tarp 13 $95.00
Serenity 8.75 $145.00
Stakes 4.7 $38.00
(MLD ultimate kit)
Without stakes With stakes
Combined Wt Savings vs moment Combined Wt Savings vs moment
Tarp + Serenity 21.75 11.25 26.45 6.55
Tarp + Bivy 20.125 12.875 24.825 8.175
Cost w/ stakes Cost/oz
Tarp + Serenity $278 $42.44
Tarp + Bivy $218 $26.67